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The Neuropsychological effects of valproate with and without carnitine supplement in a pediatric migraine sample

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Title:
The Neuropsychological effects of valproate with and without carnitine supplement in a pediatric migraine sample
Creator:
Fiano, Kristin M., 1965-
Publication Date:
Language:
English
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vi, 109 leaves : ; 29 cm.

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Subjects / Keywords:
Adolescents ( jstor )
Child psychology ( jstor )
Epilepsy ( jstor )
Headache ( jstor )
Medications ( jstor )
Memory ( jstor )
Migraine ( jstor )
Pediatrics ( jstor )
Placebos ( jstor )
Symptomatology ( jstor )
Carnitine -- adverse effects ( mesh )
Carnitine -- pharmacology ( mesh )
Carnitine -- therapeutic use ( mesh )
Migraine -- Child ( mesh )
Migraine -- Infant ( mesh )
Migraine -- drug therapy ( mesh )
Valproic Acid -- adverse effects ( mesh )
Valproic Acid -- pharmacology ( mesh )
Valproic Acid -- therapeutic use ( mesh )
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bibliography ( marcgt )
theses ( marcgt )
non-fiction ( marcgt )

Notes

Thesis:
Thesis (Ph. D.)--University of Florida, 1994.
Bibliography:
Includes bibliographical references (leaves 100-108).
General Note:
Typescript.
General Note:
Vita.
Statement of Responsibility:
by Kristin M. Fiano.

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University of Florida
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University of Florida
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Copyright [name of dissertation author]. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
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50408786 ( OCLC )
ocm50408786
002324351 ( ALEPH )

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Full Text











THE NEUROPSYCHOLOGICAL EFFECTS OF VALPROATE WITH AND
WITHOUT CARNITINE SUPPLEMENT IN A PEDIATRIC MIGRAINE SAMPLE









By


KRISTIN M. FIANO


A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA


1994




THE NEUROPSYCHOLOGICAL EFFECTS OF VALPROATE WITH AND
WITHOUT CARNITINE SUPPLEMENT IN A PEDIATRIC MIGRAINE SAMPLE
By
KRISTIN M. FIANO
A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
1994


ACKNOWLEDGEMENTS
The amount of time and effort required to conduct a study
and compile a document of this magnatude is enormous and could
not have been done without the exhaustive efforts of many
people. The author would like to extend her sincerest
gratitude to the members of her committee who ensured that
this effort was not wasted. They have provided candid,
constructive feedback at every point and are congratulated on
their superb work as committe members. Special thanks go to
a non-committee member, Paul Kubilis of Biostatistics, for his
consultation.
The author would also like to make a special
acknowledgement to her committee chairperson, Eileen Fennell,
who has filled many roles throughout the past five years. She
has served as advisor, mentor, and friend, and has left a
lasting impression on the author and her future work. Her
care and expertise are deeply appreciated.
Finally, personal appreciation is extended to family
members, particularly the author's husband Ric Fiano, who
prevented the world from falling apart on several occassions,
and to Edward and Patricia Galloway, the author's parents,
whose love and pride finally paid off.
11


TABLE OF CONTENTS
page
ACKNOWLEDGEMENTS ii
ABSTRACT iv
CHAPTERS
1 INTRODUCTION 1
2 METHODS 55
Subjects 55
Materials and Apparatus 56
Procedures 65
Hypotheses 67
3 RESULTS 70
4 DISCUSSION 80
Interpretation of Findings 83
Adolescent Noncompliance 86
Limitations of Study 93
Conclusions 97
REFERENCES 100
BIOGRAPHICAL SKETCH 108
iii


Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
THE NEUROPSYCHOLOGICAL EFFECTS OF VALPROATE WITH AND
WITHOUT CARNITINE SUPPLEMENT IN A PEDIATRIC MIGRAINE SAMPLE
By
KRISTIN M. FIANO
August 1994
Chair: Eileen B. Fennell
Major Department: Clinical and Health Psychology
Adult studies of patients with migraine suggest that some
patients have difficulties in verbal memory and attention.
Little valid research has been conducted in this area on a
pediatric sample. This study assessed the presence of
neuropsychological differences in children with migraine
compared to normals, and the effect of a medication used in
the treatment of migraine.
Whether an antiepileptic drug used for the prophylaxis of
migraine has a detrimental effect on neuropsychological
processes is also an area of controversy. Valproate, used in
this study, has historically been purported to exert fewer
negative side-effects on cognition than other antiepileptic
medications, (e.g., phenobarbital). However, such research
has primarily used epilepsy patients, thus confounding the
effect of diagnosis with drug effect. The purpose of this
iv


study was to assess the cognitive effects of valproate in
children without a diagnosis of epilepsy.
Fifteen patients recruited from the pediatric clinic at
Shands Hospital were enrolled in the study. Twenty control
subjects, similar in age and gender distribution, were
recruited from a local school associated with the University
of Florida and from a local church group. All subjects were
administered a neuropsychological battery at three testing
points. At baseline, intellectual screening was used to
assure a normal range of IQ. Measures included verbal memory,
nonverbal memory, memory span, attention, motor tapping, and
parent reports of problem behavior. Migraine subjects
received valproate monotherapy for one month after baseline
testing before their second testing. Subjects were then
divided into valproate plus carnitine supplement, valproate
plus placebo, and placebo plus placebo groups, for an
additional eight weeks. A third testing was administered at
that time. Control subjects were administered the same tests
in the same manner, but without treatment.
Children and adolescents with migraine were not found to
differ from normals at baseline. Once migraine therapy was
initiated, modest declines in attentional functioning were
observed but problems with attention did not impact memory.
v


Another finding was the significantly higher rate of
internalizing problem behaviors among the children with
migraine, which is consistent with some findings in the adult
migraine literature. Limitations and further interpretations
are discussed.
vi


CHAPTER 1
INTRODUCTION
Headaches in the general population are quite common
and, due to an estimated 150 million lost workdays, can pose
problems for the work force in this country. Approximately
90 percent of the United States population are affected by
headache, with as many as 45 million forced to contend with
headache pain (Silberstein, 1991). While headache pain for
many people is often tension related, others experience
headaches associated with the phenomenon of migraine. This
subset of headache may also have stress as a trigger, but
the mechanism is thought to be different than in the common
tension headache, and has an added hereditary component.
Historically, adults are the first to be eligible for
newly emerging medical techniques or to be the focus of
research. Gradually, however, more research is being
dedicated to these problems in children. Although children
do not readily come to mind when discussing tension
headaches or migraine, they do in fact represent a
substantial percentage of the general population affected by
such a condition (Fenichel, 1985). As a result, migraine
headaches in children have received increasing attention
from medical services over the past several decades, and
1


2
this trend is continuing among several health related
professions, including clinical psychology.
Definition and Classification of Migraine
Migraine headache is defined by a list of symptoms.
Sacks (1992) notes that headache is never the sole feature
of a migraine nor is it considered to be essential. Several
requisite features have been identified, including the
presence of periodic or recurrent headache, nausea, and
family history. Other symptoms that may co-exist but that
are not essential for diagnosis include the presence of
neurological symptoms (paresthesia, scotomata), or aura
(Bille, 1962; Rossi, 1989). Unilateral symptoms are common
and serve as a good marker for migraine in adults. These
will be discussed in further detail below.
The International Headache Society classifies headaches
into four broad categories, the first of which is migraine.
Subtypes of migraine in this classification scheme include
those without aura, with aura, ophthalmoplegic and retinal
migraine. The three remaining broad categories in this
system are tension-type headaches, cluster headaches, and
miscellaneous headaches not associated with structural
lesion. It should be noted, however, that this
classification system is designed for the adult population,
and has not been accepted for use in children.
Within the diagnosis of migraine, two common
classifications may be identified: classic and common


3
migraine. They are distinguished by the presence or absence
of aura. Rossi (1989) suggests that classic migraine, or
migraine with aura, is most likely on the same continuum as
common migraine, which is without aura. She proposes that
they differ more in the frequency rather than the quality of
the symptoms, and therefore should be considered as two
manifestations of one syndrome. Sacks (1992) identifies the
cardinal symptoms of common migraine to be headache and
nausea, while the classic migraine is characterized by aura.
Fenichel (1985) describes five broad groups of migraine
that differ slightly from those listed by the International
Headache Society. In addition to cluster headaches, and
classic and common migraine, they include basilar migraine
and migraine equivalents. Classic migraine may be
subdivided further into several categories, some which will
be mentioned briefly. Patients exhibiting focal motor
deficits, such as hemiplegia or ophthalmoplegia, can be
classified into a subgroup termed complicated migraine.
A common method of classifying migraine was provided by
Peroutka (1992). His list of subtypes and associated
symptoms is recreated in Table 1-1. Of interest is the
emphasis placed on the unilateral or contralateral
components of each migraine subtype. Again, however, this
system does not completely reflect migraine in children, as
they are more likely to exhibit bilateral than unilateral
headaches. A more important symptom in children is the


4
pulsatile nature of the headache. An interesting aspect
regarding the laterality of migraine is Wolff's (1963)
report that right-sided headaches are most common in right
handers .
Table 1-1
Classification of Migraine
Types of Migraine Symptoms
1. Common
2. Classic
3. Complicated
Hemiplegic
4. Ophthalmoplegic
5. Basilar Artery
Unilateral (80%)
throbbing headache with
associated nausea
Same as common migraine but
preceded by a visual aura
Sudden onset of hemiparesis
followed by a contralateral
throbbing headache
Unilateral eye pain and
ipsilateral ophthalmoplegia
Visual aura with alterations
in consciousness prior to
headache
Source: S. J. Peroutka (1992). Migraine. in M. V.
Johnston, R. L. MacDonald, and A. B. Young (Ed.) Principles
of Drug Therapy in Neurology. Page 162.
These neurologic symptoms associated with migraine are
most commonly transient, resolving within 24 hours. Rarely,
though, they may leave permanent neurologic deficits that
can be guite subtle, diagnosed only with sensitive
neuropsychological test measures. Brown (1977) comments


5
that there is still doubt as to whether recurrent mild
ischemia can result in lasting brain-damage, with subsequent
dementia and cerebral atrophy. However, Cole and Aube
(1990) reported three well-documented cases of migraine that
were associated with intracerebral hemorrhage. Each of
these adult cases showed spasm of the external or internal
carotid artery. They concluded that "vasospasm associated
with severe migraine attacks may result in ischemia of the
intracranial vessel walls, leading to necrosis and
subsequent vessel rupture when perfusion pressure is
restored" (page 47).
Additional Symptoms
Although not specific to children, less frequent
symptoms may be present in a child diagnosed with migraines
in addition to those described above. While migraine is
often eased by sleep (Rossi, 1989), it may be worse in the
morning. This may raise the suspicion of increased
intracranial pressure effects. Rossi reports other, less
frequent symptoms that include paresthesia, a "march" of one
to thirty minute duration that progresses from upper limb to
face, and from distal to proximal. She also reports cases
of dysarthria or aphasia, or an acute confusional state
lasting anywhere from hours to days.
Additionally, in the acute phase of an attack, migraine
patients may show nystagmus, presumably due to
vertibrobasilar ischemia. Vertigo may also be a symptom


6
present in classical migraine or basilar migraine (Brown,
1977). Brown also reports that pectoralgia, or constricting
chest pain, may be an accompanying symptom of migraine.
The most common migraine symptoms associated with aura
are visual. These visual aberrations may include
experiences such as transitory blindness, sparkling lights,
micropsia, macropsia, or even visual hallucinations. Brown
(1977) describes many of these deviations that can range
from a simple blurring of the vision, to visual field cuts,
to complete transitory blindness. Colored lights in various
shapes may also be seen. Brown reports that hallucinations
of mice or butterflies, or an entire scene breaking from
reality, are not rare. Ophthalmoplegic pain and paralysis
of eye movement, while suspicious symptoms, may also
accompany migraine. Additional common symptoms are the
nausea and vomiting which often accompany a migraine attack.
This is sometimes referred to as "abdominal aura," and may
occur for a long period of time before the onset of actual
migraine symptoms (Brown, 1977).
Finally, another group of symptoms consist of brainstem
dysfunction, commonly referred to as the basilar artery
migraine syndrome. Patients with this subgroup of migraine
may exhibit ataxia, visual aura or even loss of vision,
vertigo, tinnitus, alternating hemiparesis, and parasthesias
of the fingers, toes, and corners of the mouth (Fenichel,
1985). Brief alteration in consciousness may also result.


7
Testing performed on children with basilar migraine has
shown an abnormal caloric response (nystagmus induced by the
introduction of cold or warm water to the ear canal)
(Eviatar, 1981). Others have shown an association with
epilepsy in this group, exemplified by spike wave forms on
EEG, recurrent seizures, and partial complex symptomatology
(Panayiotopoulos, 1980). Interestingly, antiepileptic
therapy yielded relief of migraine in this group of
patients. Fenichel (1985) asserts, however, that in the
absence of associated seizure activity, antiepileptics are
of no proven value in treating these children. As will be
seen, Fenichel's belief is challenged by current medical
research.
Pathogenesis
If one is to group both classical and common migraine
together as elements of the same syndrome, then a singular
cause must be identified. Three prominent theories of
migraine pathogenesis will be presented here, as well as
other, more comprehensive, theories:
1. Vascular dvsrequlation: A common hypothesis
proposed by Wolff (1963) and also held by Rossi (1989) is
that vascular dysregulation underlies both types of
migraine. Wolff (1963) conducted experiments and
observations that indicated a vasoconstrictive and
vasodilative phase, which distinguish the prodrome and
headache phase. Fenichel (1985) describes these same two


8
vascular phases of migraine. The first, which takes place
in the preheadache stage, consists of vasoconstriction,
during which cerebral blood flow decreases. This is most
strongly associated with the internal carotid system in
classic migraine. Symptoms associated with this phase
include the visual aberrations described above (or "migraine
equivalents"), which are the most common form of aura. The
second phase, which is associated with the headache, is
vasodilation, and involves the external carotid system.
Patients describe headaches during this phase as throbbing,
pulsating, or pounding, a characteristic of the vasodilative
phase. This second phase is also distinguished by the
concomitant symptoms of migraine such as nausea or vomiting.
Welch, Spira and Lance (in Diamond, Dalessio, Graham and
Medina, 1975) have shown that a single agent (such as
prostaglandin-e) can create these differential effects in
blood flow in external (carotid dilation) and internal
(redistribution of flow) vasculature.
While this theory of migraine has support from
research, others (Sacks, 1992) claim that it is far too
simplistic in and of itself to explain fully the
multitudinous aspects of migraine. The vascular components
of the migraine process may, therefore, be only another
aspect of migraine rather than an adequate explanation.
Other, more elaborate theories therefore exist in an attempt


9
to offer a better understanding of the entire process of
migraine.
2. Serotonergic abnormalities; A second theory,
originated by Sicuteri (1961), arose from the finding that
plasma concentrations of serotonin decline at the appearance
of a migraine attack and remain significantly depressed
throughout the duration of the episode (e.g., Curran,
Hinterberger, and Lance, 1965; Hilton and Cummings, 1972, as
cited in Fenichel, 1985). In contrast, serotonin levels
rise during the migraine aura (Peroutka, 1992). This is
consistent with the evidence that serotonin applies a
powerful constrictor effect on extracranial vessels (Rigg,
1975; Sicuteri, Testi, and Anselmi, 1961). Current
hypotheses involving serotonin suggest that prophylactic
antimigraine medications function by blocking specific
serotonin receptor subtypes, whereas abortive drugs
stimulate these receptors. This may be too simplistic,
however, and, as will be discussed, the difference between
abortive and prophylactic medications may also be affected
by their action on different 5-HT receptor subtypes.
Further research has shown that the platelets of
migraineurs are different from those of nonmigraineurs in
their serotonin-releasing effect. Fenichel (1985) goes so
far as to say that migraine may primarily be a platelet
disorder, and daily aspirin may therefore act
prophylactically. The role of serotonin in migraine is


10
still unclear, but evidence supports at least partial
involvement of this neurotransmitter. Some authors (Sacks,
1992) report that one common symptom of migraine is
depression. This side effect is consistent with a serotonin
hypothesis given that serotonin is thought to play a strong
role in depression as well. Whatever the actual mechanism,
there is strong support for a serotonin hypothesis that is
based upon pharmacological evidence which has shown that
various medications that operate via serotonin can either
cause or terminate a headache episode (Diamond, Dalessio,
Graham, and Medina, 1975).
3. Spreading Depression of Leao: Finally, a
phenomenon known as the spreading depression of Leao has
been used to explain migraine pathogenesis. This electrical
phenomenon occurs in response to noxious stimulation
(Peroutka, 1992), and may be initiated by vasoconstriction
(Fenichel, 1985). This activity originates in the occipital
cortex, which may explain the predominantly visual aura.
The oligemia slows at the Rolandic and Sylvian fissures, but
may eventually reach the frontal cortex via the insula
(Fenichel, 1985). Its arrival at the sensorimotor cortex
occurs during the headache phase after the prodrome,
supporting the role of spreading depression in migraine.
In addition to the above hypotheses, the
trigeminovascular system also plays an important role in


11
migraine. Because it provides the primary afferent pathway
for head pain (Peroutka, 1992), this system has been
included in many theories of migraine pathogenesis. Neurons
in the peripheral unmyelinated fibers of the
trigeminovascular system contain substance P. This
neurotransmitter is known to be involved in several
functions: dilation of pial arteries, increase of vascular
permeability, and activation of cells involved in the
inflammatory response. This last function has an apparent
influence on head pain that can occur in the absence of
obvious external precipitating factors. According to
Peroutka (1992), the hypothesized action of the
trigeminovascular system and substance P may explain the
fact that the majority of migraines are unilateral. In
addition, the pain in migraine is referred to areas
innervated by the trigeminal nerve. Finally, the aura most
commonly associated with migraine is a result of "posterior
circulation dysfunction", this posterior area being densely
innervated by the first division of the trigeminal nerve.
Solomon's (1993) model of migraine incorporates several
concepts, some of which are common to the above mentioned
theories. First, he suggests that the trigeminovascular
system serves the purpose of protecting the brain, just as
other pain systems work to protect other parts of the body
by signaling problems, which, in this case, would include
ischemia or toxins. The trigeminal nerve can be stimulated


12
by both electrical (neuronal) and chemical factors. The
chemical factors would include neurotransmitters, such as
serotonin, and may work directly (hormones affecting
prostaglandins) or indirectly (e.g., REM sleep reducing
serotonin release from the dorsal raphe nucleus). This
latter mechanism may help explain why sleep often eliminates
the migraine in many patients. Whatever the trigger, the
stimulation may result in a release of tachykinins from the
trigeminal nerve, such as substance P, into the meningeal
and dural blood vessels. This results in the release of
histamine, vasodilation, and the platelet release of
serotonin. The release of substance P results in
inflammation and blood vessel swelling. Finally, this
swelling and inflammation causes distention of the cranial
arteries and the headache pain.
Solomon's model has the appeal of explaining many of
the components known about migraine, including a role of
serotonin, the cause of the actual headache pain, the
benefit of antihistamines, the purpose of sleep to alleviate
the migraine, and the possible mechanisms of numerous
triggers. The pain involved in migraine may be caused by
local inflammation and sensitization of nociceptors by
substance P. In any case, this model emphasizes the
importance of an ischemic or neurochemical noxious trigger
that stimulates the trigeminal nerve. This model does not


13
exclude other theoretical perspectives, but may instead help
to link them together in a more comprehensive model.
A more functional model of migraine was proposed by
Crisp, Levett, Davies, Rose, and Coltheart (1989). They
conducted a study on 57 migrainous adult patients, 26 of
whom had classic migraine with primarily unilateral
prodromata. Among these subjects, all were right handed,
and 19 had left hemisphere prodromata. One had right
hemisphere prodromata, but had a history of only one
migraine. Others were indeterminate or bilateral. The
findings indicated that unilateral classical migraine
categorized according to prodromal clinical characteristics
in right-handed people is exclusively a left (dominant)
hemisphere phenomenon. These researchers suggested that
this type of migraine was a result of a relative dysfunction
of the ipsilateral hemisphere, rendering it susceptible to
overload of information to be processed. In this case, left
hemispheric prodromata would be due to dysfunction in the
properties of the left hemisphere, such as verbal
processing. Although Crisp et al. did find some support for
their hypothesis, their interpretation may very well be
incorrect. That is, if an individual experiences a long
history of unilateral migraine (their subjects' mean length
of migraine history was nine years), then the processes
involved, such as those described by other theorists above,
may result in a compromise of the systems of that particular


14
hemisphere. Additionally, the stimuli that these
researchers used to measure spatial ability had qualities of
verbal processing and attentional demands rather than being
a relatively pure measure of spatial processing.
Nevertheless, the finding that right handers with unilateral
migraine have a strong tendency towards left hemisphere
involvement as measured by prodromata is intriguing. These
researchers screened out left handers for purposes of their
research, but reported that of the five subjects they found
with right hemisphere unilateral migraine, all five were
left handers. Although these researchers assessed numerous
patients with unilateral pain, persistent unilateral pain
may suggest other factors, such as arteriovenous
malformations.
Demographic Variables
Prevalence
Although there are discrepancies, most place the
prevalence of childhood migraines at approximately four
percent (Bille, 1962). There is evidence that migraine has
a hereditary component, which is presumed to be autosomal
dominant, according to Fenichel (1985). Brown (1977) states
that as many as 90 percent of migraine cases have a family
history, also suggesting autosomal dominance. Fenichel
(1985) purports that the prevalence of migraine is 2.5
percent in children under 7, which then rises to 5 percent


15
in children past that age. In the older age group, females
are slightly over represented at a 3:2 ratio.
Outcome
According to Fenichel (1985), the frequency and
intensity of migraine tends to decrease with age. However,
some studies have shown that, as a group, children with
migraine die at younger ages than nonmigraineurs (Levitn,
Malvea, and Graham, 1974). Also, presumably due to the
vascular mechanisms involved, this group has a higher risk
for stroke, especially in women taking oral contraceptives
(Fenichel, 1985).
Personality Differences
There have been several studies exploring personality
characteristics in children with migraines. Brown (1977)
asserts that, contrary to earlier beliefs, migraine is not
associated with high intelligence. Common findings from
more personality oriented investigations describe migraine
children as dejected, depressed, or withdrawn, with the
potential for becoming stubborn, inflexible, argumentative,
and rebellious (Wolff, 1963). Wolff also reported that
memory and attention can be impaired during the headache.
Bille (1962) has described these children as being more
anxious, fearful, and nervous than their same aged peers
without headaches. Most of the earliest studies employed
nonstandardized questionnaires or simply clinical impression
(e.g., Menkes, 1974). As a result, findings were mixed and


16
yielded little useful data. Others have attempted to avoid
such problems through the use of standardized instruments
and appropriate control groups.
Andrasik, Kabela, Quinn, Attanasio, Blanchard, and
Rosenblum (1988) conducted a study to examine the
personality characteristics of two groups of children with
migraines. An older, adolescent group consisted of subjects
between the age of 13 and 17, while the ages of children in
the younger group ranged from 8 to 12. All subjects were
age matched with controls. The measures utilized in this
study were primarily parent report and self-report
questionnaires. Findings from this study were that headache
sufferers earned significantly higher scores on measures of
depression from several scales, and expressed a higher
number of somatic complaints, even with the omission of
headache related questions. Andrasik et al. also found
that, overall, the adolescent group was less successful in
coping with their migraines than the younger group. They
hypothesized that adolescents, while trying to develop their
independence, at the same time had unpredictable migraine
attacks that often ruined social plans. This
unpredictability may therefore create a need to be dependent
on a caretaker or foster feelings of anxiety. Andrasik et
al. found that this pattern was particularly true for males,
and suggested that, because of accepted roles for males and
the expression of their pain or discomfort (which does not


17
include crying or openly admitting pain), male adolescents
had to find alternative methods of expressing their pain.
This often came in the form of externalizing behaviors or
moodiness.
In contrast to these findings, Cooper, Bawden,
Camfield, and Camfield (1987) found from their study of
children with migraine, that such children do not report a
higher number of life stressors than their best friends
without migraine. This was found despite the fact that the
children with headaches and their parents both reported that
stress is the most common trigger of migraine attacks.
Cooper et al. (1987) do agree with Andrasik et al. in the
finding by parent and self-report measures, that migraine
children have significantly higher ratings on scales such as
somatic concerns and depression. Andrasik et al. (1988)
suggest that migraine children do not experience greater
life stress (based on questionnaire) than normals, which
would suggest the differences in somatic concerns and
depression are related to the migraine rather than the
migraine resulting from stress. Furthermore, despite no
significant difference between the headache and control
groups on stress or anxiety, Cooper et al. (1987) did
provide evidence suggesting that the most anxious children
in their sample had the most frequent and severe headaches.
They concluded that stress and anxiety exacerbate migraines


18
in children who have inherited the migraine tendency, rather
than being a direct cause of migraine.
Neuropsychological Differences
A recent paper by Kohler and Fennell (1992) examined
the differences in performance on neuropsychological tests
between adult migraine patients and normal controls. The
results of this study suggested that migraineurs perform
significantly worse on verbal and nonverbal memory tasks
than age matched controls. This difference was largely
attributed to the common migraine group, as there was no
significant difference between the classic migraineurs and
controls. No groups showed differences on learning tasks.
These researchers hypothesized that those migraineurs with
aura (i.e., classic migraine) may be able to cope better
with an impending migraine attack due to the benefit of a
warning sign, which would enable them to use medications
that may prevent the headache phase of the migraine.
Presumably, those patients who experience fewer headaches
may therefore be at a lower risk for ensuing ischemic damage
that could negatively impact memory functions.
Neuropsychological studies of patients with migraine,
however, have yielded mixed results. A study by
Leijdekkers, Passchier, Goudswaard, Menges, and Orlebeke
(1990) compared the neuropsychological performance of 37
adult female migraineurs with that of 34 nonheadache female
controls. They employed a variety of tests, including


19
measures of verbal learning, short term memory, reaction
time, sustained attention, and motor tapping. They did not
find significant differences on any of their measures of
cognitive functioning, nor did they reveal any effects of
migraine history or medication use. Further dividing the
migraine subjects into classical versus common also did not
result in group differences. They did, however, note higher
trait and state anxiety levels, state depression, and less
vigor, based on self-report measures, in the patient group
compared to the control group.
Yet another set of findings by Hooker and Raskin (1986)
provides evidence for a different interpretation of the
question of neuropsychological differences in migraineurs.
They administered a battery of tests including motor tests,
verbal and nonverbal memory tests from the Wechsler Memory
Scale, Trail Making Test, the Wisconsin Card Sorting Test,
and the Tactual Performance Test (TPT). Thirty-one migraine
subjects and 15 controls were used in this study, with a
combination of males and females. The authors found that
subjects with classic migraine exhibited decreased upper
extremity motor speed and dexterity, less efficient learning
of new associations between dissimilar symbols, and
dysphasic errors. Combining the classic and common migraine
subtypes into one group revealed poorer delayed free recall
for verbal material and decreased performance on the TPT.
These researchers argued that the classic migraineurs


20
demonstrated a larger scope of functional compromise than
the common migraineurs, and suggested therefore that the
classic form of migraine reflects a primary disturbance of
the central nervous system. Their findings are in direct
contrast to the study by Kohler and Fennell (1992), which
indicated that the common migraineurs experienced greater
neuropsychological impairment. Hooker and Raskin (1986)
also showed that no single class of drug showed differential
impact on the Halstead-Reitan Average Impairment Index,
which is consistent with the findings by Leijdekkers, et al.
(1990).
In another study, Ai (1992) administered a
neuropsychological test battery to 48 migraineurs, 20
patients with functional headache, and 20 controls. The
primary result was that migraineurs had higher dysfunction
in the areas of motor, perception, memory, abstract thought,
attention, and information processing. Additionally, the
dysfunction was worse with a longer course of migraine.
Crisp, Levett, Davies, Rose, and Coltheart (1989)
demonstrated in their study of 57 male and female patients
that migraineurs as a group (i.e., classic and common
migraine) exhibited poorer verbal and spatial performance
than controls.
Despite the evidence resulting from these studies that
true differences do exist between migraineurs and matched
controls, another study provides evidence that there are no


21
significant differences. Burker, Hannay, and Halsey (1989)
examined 47 migrainous female college students and 24
controls. No significant differences were found on the
Halstead Reitan Neuropsychological Test Battery and other
memory tests. Like Leijdekkers et al. (1990), however, they
did observe personality differences as measured by the
Minnesota Multiphasic Personality Inventory (MMPI) on
Hysteria and Paranoia scales between classic and common
migraineurs, and differences on the Hypochondriasis and
Hysteria scales between all migraineurs and controls.
It is unclear what factors are contributing to these
divergent findings. One possibility is that many of the
findings by Hooker and Raskin (1986) are spurious, resulting
from the numerous statistical analyses they conducted on a
relatively small sample size. Kohler and Fennell (1992)
employed age and sex-standardized scores in a multivariate
analysis which limited the number of tests of significance
and controlled for the correlation between measures.
Leijdekkers et al. (1990) attempted to use relatively basic
behavioral tests rather than more complex tests, which they
felt would be overly sensitive to extraneous influences and
lead to spurious results. This may also have served to mask
real differences between the patient and control groups.
The diverse collection of research in this area does
not appear to support strongly any one hypothesis.
Different test batteries, methods of analysis, or individual


22
differences may all contribute to the inconsistencies
reported here. Additionally, these studies were conducted
on adult patients, which may be a vastly different
population than migrainous children, in part because of the
longer history of a potentially damaging process in the
adults. Also, children are less commonly diagnosed with
classic migraine. This dimension has been significant in at
least several studies and may lead to different findings for
an adolescent population. Unfortunately, no comparable
research base exists to date on children with migraine.
Imaging Techniques and Coincidence with Epilepsy
Some investigators assert that the use of EEG, cranial
computed tomography (CT), or other types of brain imaging
techniques, constitutes an excess in diagnostic procedure
with migrainous children (Prensky and Sommer, 1979).
Others, however, declare that such diagnostic tools have
value in the research and assessment of migraine. For
example, Alvarez-Cermeno, Gobernado, Freije, Zaragoza, and
Gimeno (1984), reported two cases of pediatric migraine
which showed CT contrast enhancement in the occipital
region. They stated that although these areas were poorly
defined, the important finding was that the CT changes were
evident only during the active phase of migraine.
Regional Cerebral Blood Flow (rCBF) has also been
examined in children with migraine. Roach and Stump (1989)
concluded that regional reduction in the expected blood flow


23
surge after C02 inhalation was a frequent finding, lending
support to the already strong belief that pediatric migraine
is a disorder of vasomotor function. However, others argue
that there may be no change in cerebral blood flow in
migraine without aura (Silberstein, 1991). In a study on
adults with migraine, Thie, Carvajal-Lizano, Schlichting,
Spitzer, and Kunze (1992) attempted to measure cerebral
vasoreactivity (CVR) via trascranial Doppler ultrasound
(TCD) during cognitive and motor tasks. They imaged the
left middle cerebral artery (MCA) and left posterior
cerebral artery (PCA) and compared CVR in migraineurs to
controls. Although they found that migraineurs as a group
had higher mean flow velocities for photic stimulation,
observation of complex images (both PCA measures), and the
cognitive task (MCA measure), they cautioned against any
strong conclusions. They stated that individual differences
were too great to allow this form of imaging to be a
sufficiently sensitive measure of migrainous activity.
Migraine is not an uncommon associate of epilepsy,
particularly when the migraine is associated with an aura
(De Romanis, Buzzi, Feliciani, Assenza, and Agnoli, 1991).
Fenichel (1985) asserts that familial epilepsy syndromes and
migraine are associated for the following reasons:
(1) they are both familial, paroxysmal, and associated
with transitory neurologic disturbances;
(2) there is an increased incidence of epilepsy in
migraineurs and migraine in epileptics;
(3) headache can be a seizure manifestation; and


24
(4) abnormal electroencephalograms are common in both
disorders, (p. 80)
The mere presence of a correlation, however, does not
confirm that epilepsy and migraine are biologically linked.
Furthermore, abnormal EEGs are not indicative of any
specific disorder, as some portion of the normal population
shows evidence of abnormal electroencephalographic activity.
Other similarities exist, however. It may be that
repeated migraine creates compromised tissue that could
result in epileptic discharges. Also, when a child has
symptoms of confusion, personality change, rage reactions,
and hallucinations, they may mimic the symptoms of a partial
complex seizure. Furthermore, the flicker-rate of scotomata
in migraine is of the same frequency of the stroboscopic
illumination that is most likely to cause epileptic seizure
(Sacks, 1992). Jackson (1931, as cited in Sacks, 1992)
asserted that migraines were in fact cases of epilepsy of a
sensory nature, with the headache and vomiting representing
the post-paroxysmal period. Other evidence does lend
support to the correlation between epilepsy and migraine,
although the precise relationship is unknown.
EEG recordings between migraine attacks may reveal
sharp or spike waves from the temporal-occipital or
temporal-parietal regions, and reflect clinically reported
symptoms from children with migraine. These children often
report visual hallucinations, hemianopsia, or amaurosis in


25
conjunction with migraine attacks (De Romanis et al., 1991),
which is consistent with photophobia reported in migraine
sufferers without epilepsy. In many cases, migraine is seen
in combination with epilepsy such that an attack may be part
of the prodromal phase of the epileptic event, but there may
also be a dissociation between migraine and epilepsy such
that the migraines continue years following the resolution
of the seizure disorder.
Because the occipital EEG wave pattern is so common in
childhood migraine headaches (e.g., De Romanis et al.,
1991), it may be that even in the absence of clinically
evident seizure behavior, subclinical abnormal activity is
responsible for migraines. Why the posterior cortical areas
are more susceptible to such activity may be due to a
neuronal sensitivity in the occipital region (De Romanis et
al., 1991). This, in conjunction with the fact that visual
patterns may trigger migraine as well as epilepsy (Brown,
1977), lends support to a relationship between the two
syndromes. In fact, Sacks (1992) considers migraine to be
on the "borderland" with epilepsy and other neurological
disorders, suggesting that they share similar symptomatology
and possibly similar underlying mechanisms. He suggests
that the paroxysm in migraine can be 20 times slower than in
the epileptic counterpart.
Additional evidence from EEG data on migrainous
children reveals no difference between these children and


26
age-matched controls between headaches. However, Seri,
Cerquiglini, and Guidetti (1993) found that during visual
aura a decrease in occipital alpha power contralateral to
the affected hemifield was evident in all migraine patients.
Furthermore, this was followed by an increase in delta power
in the bilateral frontal regions. During the headache, an
increased delta activity in posterior-temporal and occipital
electrode sites was also shown. The involvement of
occipital areas, especially during visual aura, is
consistent with neuroanatomy. The bilateral frontal
involvement, however, may reflect neuropsychological
impairment, probably quite subtle, that may include problems
with attention. Whether such an impairment could be
measured between events remains to be seen. Such
differences in EEG background activity (slowing) has been
observed between migraineurs, idiopathic epilepsy patients,
and controls, with no significant difference within the two
patient groups (Farkas, Kohlheb, Benninger, and Matthis,
(1992) .
Like migraine, epilepsy may manifest with the
predominant associated feature of abdominal pain, sometimes
termed "abdominal epilepsy". The differentiation between
abdominal migraine and abdominal epilepsy is not entirely
clear cut on the basis of subsequent convulsions or EEG
(Brown, 1977). Prensky (1976) reports that children with


27
abdominal pain as their major symptom seem to have more
epileptiform EEG changes that those with simple migraines.
Treatment
Behavioral
The most common factor implicated in triggering a
migraine is psychological stress (Rossi, 1989) or emotional
tension (Brown, 1977). In pediatric cases, the frequency of
migraine is much higher during the school year than in the
summer, also implicating psychological stressors. This
finding suggests that an ideal treatment for migraines is
behavioral.
Behavioral approaches to the treatment of pediatric
migraine consist primarily of biofeedback, which can be
defined simply as bringing those bodily processes that are
normally involuntary and unconscious under voluntary control
(Gascon, 1984). This often requires the use of electronics
that have the capability of translating biological signals
(e.g., vasodilation) into signals that can easily be
detected (e.g., auditory signal). One method of biofeedback
is EMG, which is commonly used to assess frontalis muscle
activity, typically in tension headaches. For migraine,
however, temperature biofeedback is commonly employed as a
behavioral technique designed to influence vasoconstrictive
processes. While many of the treatment studies conducted in
adults have not yielded strong findings (Gascon, 1984),
children may be more promising candidates for this type of


28
treatment. Womack, Smith and Chen (1988) report that
children naturally like the use of imagery and biofeedback,
and are often enthusiastic about the procedures. Gascon
(1984) has suggested that children learn biofeedback
techniques more quickly than adults, and that if effective,
such a treatment option has obvious desirability. Brown
(1977) recommends that regular drug therapy be reserved for
only the most severe cases. While medications are still
most common, behavioral approaches offer treatment that
allow the child to feel more in control of their migraines,
as well as to avoid the problems of drug side effects.
In a study conducted by Womack, et al., (1988),
children were asked to keep diaries of their headaches.
They then participated in biofeedback (EMG and/or skin
temperature for most subjects), as well as relaxation and
mental imagery. After eight weekly sessions and 12 month
follow-up, results showed that, of 29 subjects, 48 percent
of the migrainous patients were headache-free, and an
additional 41 percent showed a greater than 50 percent
reduction in headache frequency. Eighty-six percent showed
a decrease of over 50 percent in perceived intensity.
Despite the fact that Womack et al. did not employ a control
group, these findings are encouraging. Many factors may
have been involved, however, such as the simple act of
monitoring the pattern of headaches through the use of a
diary, or even a treatment placebo effect, and the


29
investigators made no attempt to tease out possible
differential effects. Also, since migraine headaches may be
erratic in their pattern of occurrence, some changes may
have been attributable to normal variations in occurrence.
Additionally, the short duration of the study may not be
sufficient to determine if there was an actual change or a
temporary placebo effect. Also, each subject received a
combination of treatments (imagery, relaxation, and
biofeedback). This would make it difficult to determine
what aspects of treatment, if any, played a significant
role. Despite the shortcomings of the study, the authors
conclude that behavioral treatment has a high probability of
improving headache condition in children and adolescents.
Guarnieri and Blanchard (1990) attempted to assess the
effectiveness of biofeedback in a clinic treated group
versus a home practice group. They claim to have found a
clinically significant reduction of headache frequency and
intensity, though these numbers did not reach statistical
significance. There was no significant difference between
the two groups on measures of expectation or symptom
improvement, suggesting that home treatment is equally
effective. Burke and Andrasik (1989) found similar results,
adding that the gains made by their subjects were stable,
maintained through a one-year follow-up period. Finally,
Smith, Womack, and Chen (1989) found no correlation between
age, sex, headache type, hypnotizability, and clinical


30
outcome. Most recently, these findings were strengthened by
the similar results of McGrath, Humphreys, Keene, Goodman,
Lascelles, Cunningham, and Firestone (1992) who showed that
self-administered behavioral treatment was effective with
adolescents, even at a one year follow-up. An adult follow
up study on the long term effects of training in relaxation
and stress coping was conducted by Sorbi, Tellegen, and Du
Long (1988). They found that the positive results from
behavioral and cognitive treatments were still in effect
after a period of three years.
Diet
Some researchers have considered allergies and diet as
possible triggers for migraine attacks (Brown, 1977),
including foods rich in tyramine or phenylethylamine.
Consequently, a modified diet has been attempted in the
treatment of migraine. Specifically, tyramine, which is
known to release serotonin from platelets, has been reduced
in diets for clinical treatment, or added to the diets of
controls to precipitate migraine experimentally. This
relationship has yet to be firmly established.
Medication
Some common medications used in the treatment of
migraine headaches in children include propranolol,
ergotamine tartrate, pizotifen, cyproheptadine, and calcium
channel-blocking agents (Rossi, 1989). Some of these (e.g.,
ergot derivative) are most effective when administered


31
during the aura, if present, prior to the onset of the
actual migraine. Fenichel (1985) suggests the use of two
medications, ergotamine and isometheptene mucate, for the
acute treatment of migraine. For ergotamine, the chief
mechanism of operation is constriction of the extracranial
blood vessels. The latter drug, isometheptene mucate or
Midrin, is a sympathomimetic agent which constricts
extracranial veins, and has been shown by a few studies to
be at least as effective, if not more, than ergotamine.
Brown (1977) suggests that ergotamine will ease headache of
common migraine, but may actually aggravate the ischemic
neurological abnormalities of complicated migraines.
For migraine prophylaxis, Fenichel (1985) lists many
drug classes, including serotonin agonists and antagonists,
antidepressants, antihistamines, vasoconstrictors,
vasodilators, tranquilizers, calcium-blocking agents, and
antiepileptics. Solomon (1993) states that prophylactic
medication operating via serotonin are specific to 5-HT2
receptors. Antagonists "are able to inhibit serotonin from
inducing an arachidonic acid-derived inflammatory state."
(p. 202). This explains why such a medication can operate
only prophylactically, because once the inflammation has
been initiated, the 5-HT2 antagonist would be useless.
Gascon (1984) also lists antiepileptic drugs as being
among the group of effective medications for migraine, and
asserts that these drugs are most effective in preadolescent


32
children. Phenobarbital, phenytoin, carbamazepine, and
valproic acid are among the many antiepileptic drugs used
for this purpose. Moreover, there is no clear indication
that associated epileptiform activity is necessary for the
effective use of antiepileptics in children with migraine.
The mechanism in which antiepileptic drugs affect migraine
is yet to be discovered, and to date, there is a surprising
lack of well conducted studies (e.g., prospective, double
blind, placebo controlled) in this area. However, according
to Solomon (1993), the action of these medications, at least
that of valproate, would operate at the level of 5-HT2
receptor site in order either to prevent serotonin-induced
cerebral vasospasm and ischemia, which may activate the
trigeminal nerve, or by inhibiting the arachidonic acid
metabolism as described above.
Sorensen (1988) conducted a prospective study of the
efficacy of valproate in 22 adult patients with severe
headache resistent to previous prophylactic treatment.
Subjects were followed over an average of six and a half
months to assess the efficacy of the medication. Eleven
patients were free from migraine, 6 demonstrated a
significant reduction in freguency, and one had no change.
Four of the patients withdrew from the study because they
could not tolerate the withdrawal of their previous
medication (injected narcotic). Sorensen also attempted a
withdrawal of the valproate for four weeks with three


33
patients who were free from the attacks. In all three
patients, their headaches recurred, but subsequent
administration of valproate again caused the disappearance
of the headaches. Side effects noted included drowsiness in
one patient and slight weight gain in three females, and two
patients reported severe cold painful paresthesias of the
extremities only during the first days of treatment.
Unfortunately, a placebo effect cannot be ruled out in this
study because no control group was used and patients and
experimenters were unblinded. However, because these
patients had previously tried numerous medications without
apparent relief, it is not likely that these results are
solely due to a placebo effect.
Cognitive Effects of Anticonvulsant Medication
Despite the number of studies conducted for the purpose
of examining the differential cognitive or
neuropsychological effects of antiepileptic medication, very
few have employed good experimental methods such as double
blind designs, adequate control groups, or appropriate
neuropsychological tests. Therefore, a need remains for
solid research to determine the extent to which various
antiepileptics affect cognitive and behavioral aspects of
children with or without epilepsy. In contrast, somewhat
more information exists on the effects of beta blockers and
analgesics, and suggests that both of these medications


34
negatively affect verbal memory and learning (e.g., Kohler
and Fennell, 1992), at least in adults.
Some authors (e.g., Meador, Loring, Huh, Gallagher, and
King, 1990) contend that most of the more popular
antiepileptics have similar treatment efficacy, and
therefore differential cognitive effects should be given
appropriate consideration. Trimble and Cull (1988) reviewed
over a dozen studies on the effects of several
antiepileptics in children with varying types of epilepsy
and summarized their findings as follows: Phenobarbital
substantially impairs behavior, whereas valproate and
carbamazepine have little effect. Other medications have
far less data and await further research.
Adult Studies of Cognitive Effects of Valproate
In a longitudinal study of adults with a variety of
types of epilepsy, Dodrill and Wilensky (1992) followed 198
patients for five years that were on phenytoin monotherapy
or polytherapy. They concluded that there was no evidence
that long term administration of phenytoin is associated
with loss of cognitive abilities over time. Instead, they
infer that it is the effects of an epileptic condition that
cause cognitive decline, and because their subjects had
milder cases of epilepsy, no deterioration could be seen.
In order to lend support to their belief that it is the
epilepsy that causes the cognitive changes and not the
medication, drug trials on non-epileptic groups would be


35
beneficial. Because their study included adults only, they
admit that their results should not be applied to children
without further research on younger, pediatric populations.
Corbett, Trimble, and Nichol (1985) did show cognitive
deterioration in children on long-term antiepileptic
therapy, with those with higher phenytoin levels having
lower performance IQs. Verbal IQ was not affected.
Gallasi, Morreale, Lorusso, Procaccianti, Lugaresi, and
Baruzzi (1990) employed a withdrawal of medication design in
an adult epilepsy group of 20 patients who were seizure-free
for at least two years. They tested their subjects at four
points in time, ranging from baseline to 21 months. They
found significant differences between the epilepsy group and
controls on measures of reaction time and a global
performance measure that included all tests. This
difference was found at baseline and the second testing
(drug reduced to half). They compared the results to normal
controls who were only tested once, and asserted that the
gradual improvement they found was due to the gradual
removal of valproate. However, a significant practice
effect could account for this finding, since the controls
were not tested repeatedly. It is also noteworthy that
their findings, although statistically significant, were not
clinically significant, as none of the patients had noticed
any changes in the abilities measured. This finding is


36
consistent with the literature, which has shown only mild
differences, if any, as a result of valproate.
A study conducted by Sommerbeck, Theilgaard, Rasmussen,
et al. (1977) evaluated the psychotropic effects of
valproate in a heterogenous sample of epileptics. The
patients were given either valproate or placebo in
conjunction with other medications. This is a drawback for
this study that purported to find minor differences with
concurrent administration of valproate, because the impact
of the other medications cannot be assessed adequately.
Measures used included Digit Span, Paired-associate
learning, simple reaction time, Stroop's Color Naming test,
Hidden Patterns test, time estimation, a cancellation task,
a visual gestalt test, and motor tapping. The results
suggested that valproate caused declines in psychomotor
tempo and visuo-spatial analytic and synthetic functions.
However, these results are also suspect due to the small
sample size (20 patients) and the heterogenous nature of the
sample (e.g., the ages ranged from 13 to 63 years). Such
extraneous factors do not allow for strong conclusions.
Bittencourt, et al. (1992) also examined the three
medication groups (valproate, phenytoin, and carbamazepine)
in adults during drug administration. They found that the
epilepsy patients on phenytoin performed significantly worse
on the immediate recall for pictures than controls, those on
carbamazepine performed worse on the Stroop test than


37
controls, and those on valproate did not demonstrate any
appreciable difference from controls on these tests.
In addition to the research involving patients with
epilepsy, some researchers have attempted to assess the
effects of antiepileptics in normal controls. For example,
Boxer, Herzberg, and Scott (1976) found that a single dose
of valproate (400 mg) had hypnotic effects on medical
students used as controls. While this effect was greater
with the concurrent administration of phenobarbital, the
important finding was that valproate alone could produce
such effects. This study, however, was not without
methodological problems. The researchers only used eight
male subjects who were given only three psychological tests.
These tests consisted of a subjective report of sleepiness,
Digit Symbol, and a card sorting test (the authors did not
specify which). None of these measures showed any
differences. Their findings were based exclusively on EEG
record during a 30 minute period after only one dose of the
medication, one hour after administration. Perhaps the
biggest drawback to the study was their failure to measure
blood levels of the drugs used. Although the dosage was
equal for each subject (400 mg of valproate), there was no
apparent attempt to assess if the drug was in a therapeutic
range that would make the comparison more relevant to
clinical use.


38
In a better designed study, Thompson and Trimble (1981)
studied the effects of sodium valproate on cognitive
functioning in normal volunteers. Subjects were
administered 200 mg of sodium valproate or placebo for a
period of two weeks in a double-blind cross-over design. No
significant effects on memory, concentration, perceptual
speed, or motor speed were found. However, subjects did
require a significantly longer amount of time to answer
questions in a decision making task. Several reasons for
these results are possible. The dosage was less than that
used in the Boxer, Herzberg, and Scott (1976) study and may
therefore not create as strong an effect. The tests used by
Thompson and Trimble (1981) are not particularly demanding,
as memory was assessed through a simple recognition
paradigm, and other tasks were well within the range of
abilities for such a normal subject group (i.e., medical
students). Therefore, assessing the effects of valproate
would seem to necessitate using sensitive test measures to
reveal differences between control and experimental groups.
In order to investigate the effects of valproate on
sleep, reaction times, and visual evoked potential (VEP),
Harding, Alford, and Powell (1985) administered placebo,
low-dose, and high-dose conditions to 10 normal adult
volunteers. Withdrawal of medication effects were also
assessed. They found no significant treatment effect for
simple reaction time, nor did they find any differences in


39
either the latency or amplitude of the VEP. A decrease in
rapid eye movement and an increase in delta activity during
sleep was seen under the high-dose condition. Their lack of
findings could be a result of their small sample size,
particularly for the reaction time data, which was available
for only 6 of the 10 subjects due to technical difficulties.
The results from this study are consistent with those of
Thompson and Trimble (1981), however.
Child Studies
Duncan, Shorvon, and Trimble (1990) attempted to
examine the differences between several antiepileptic agents
(i.e., phenytoin, valproate, and carbamazepine) when they
were withdrawn from 58 children with partial and generalized
epilepsy. This method of assessing improvements following
the discontinuation of medication has the drawback of
assuming that these drugs have no residual, long term
effects. In fact, Duncan, Shorvon, and Trimble asserted
that their results supported the view that, since removal of
valproate resulted in the least improvement on
neuropsychological tests, it had the least negative impact
on the children who were taking it. This conclusion, while
it may have some validity, could be a misinterpretation of
an opposite effect. That is, if valproate has the more
detrimental, long lasting cognitive effects of the three
drugs, the results would have been the same. Regardless of
the final interpretation, Duncan, Shorvon, and Trimble found


40
that finger tapping was improved upon removal of all three
drugs, while letter cancellation, digit symbol substitution,
digit span, and serial subtraction, were not significantly
affected by the removal of valproate.
In a similar design, Blennow, Heijbel, Sandstedt, and
Tonnby (1990) reported tentative results in the midst of
their ongoing study. At the time they reported these
interim findings, 69 children with various types of epilepsy
had been studied, along with 69 matched controls (the
authors did not specify how control subjects were matched).
They described patterns such as faster reaction time at the
expense of accuracy for the valproate and carbamazepine
groups, slightly decreased motor fluency in the right hand
for the valproate and phenytoin groups (in contrast to
Duncan et al., 1990), and short-term memory decreases in all
groups treated for epilepsy. The last finding is difficult
to separate from the effects of long term epilepsy, however,
despite their use of a control group. The heterogenous
epilepsy group is also a common drawback in the study of
cognitive effects of antiepileptic medications, particularly
when the different types are not considered in analysis.
Vining, Mellits, Dorsen, et al. (1987) conducted a
double-blind counter balanced cross-over study of 21
children with epilepsy, comparing the cognitive impact of
phenobarbital and valproate. Patients were given a
neuropsychological battery three times: at baseline, after


41
six months on one medication, and after six months taking
the other medication. The battery consisted of tests
including intellectual assessment (Wechsler Intelligence
Scale for Children-Revised), measures of attention span and
sustained attention, motor tasks, achievement tests, mazes,
and the Bender-Gestalt, among others. While both
medications controlled seizures equally well, these authors
found that those patients on the phenobarbital performed
worse on certain subtests of the WISC-R (including verbal
and performance subtests), paired associate learning,
reaction time for errors on a continuous performance test,
and arithmetic achievement scores. Further, they found that
the patients on valproate earned more favorable scores on
parent questionnaires than those on phenobarbital. While
intriguing, these results must be considered tentative
because of the statistics used. With only 21 subjects,
these authors employed over 90 t-tests. Their findings may
be spurious rather than reflecting actual differences
between the side effects of the two drugs.
To assess the effects of dosage, fluctuations in
concentration, and diagnosis, Aman, Werry, Paxton, and
Turbott (1987) studied the effects of valproate in 46
children with epilepsy who received valproate monotherapy.
Three sets of tests were administered: measures of short
term memory, continuous performance task, mazes, pursuit
rotor task, and Matching Familiar Figures, with one week


42
intervals. The timing was altered to take advantage of
medication dosing (one test was administered pre-dose,
another post-dose), with the first test administered to
minimize subsequent learning effects. Subjects with lower
doses performed better on the psychomotor tasks than those
with higher doses. Timing of the dosing (pre- or post) did
not have an effect. Again, these authors over used the t-
test without considering their sample size. The age-range
of their patients was also rather broad (4.4 years to 15.4
years), making accurate interpretation of their data
difficult.
Forsythe, Butler, Berg, and McGuire (1991) utilized
more rigorous criteria for both subject population and test
measures. They targeted only new cases of epilepsy with no
neurological deficit, who had had either three tonic-clonic
seizures, three complex partial seizures, or three partial
seizures with secondary generalization. They employed an
appropriate experimental design, and monotherapy as opposed
to polytherapy. Michael Trimble served as consultant on
choosing appropriate test measures that would be most
sensitive, least affected by practice effects, high in
convenience, and would cause minimal fatigue and boredom.
Subjects were randomly assigned to one of three medications:
carbamazepine, phenytoin, and sodium valproate. After six
months of treatment, children on sodium valproate performed
significantly better on memory scores than children on


43
carbamazepine, and this difference was even greater after a
year. Speed of information processing was impaired in both
the carbamazepine and phenobarbital groups, this being
evident after only one month of treatment. The better
performance on memory scores with those on valproate
relative to those on carbamazepine may represent an actual
drug effect with the carbamazepine exerting a more negative
influence on memory. However, much of the research in this
area has employed tests that may not be as sensitive to
subtle, sub-clinical effects of memory and attention.
Future research should target these areas with measures less
susceptible to a ceiling effect or more likely to reflect
subtle differences.
In summary, several broad conclusions can be made about
the cognitive effects of antiepileptic medications.
Consistent with Vining's (1987) descriptions, these drugs
can be ranked by the degree to which they affect cognition.
Phenobarbital, which historically has the worst effects on
cognitive functioning, has its primary effect on short-term
memory, but also adversely affects long-term memory,
concentration, and symbol manipulation. Phenytoin
selectively impairs abilities related to problem solving and
visuomotor tasks, timed motor task, and attention.
Carbamazepine appears to have similar effects, although at
lower magnitudes. Finally, valproate appears to have
minimal effects, but may influence the most subtle aspects


44
of cognition. This makes sensitive neuropsychological tests
requisite in the assessment of differential effects.
Additionally, the research on the cognitive effects of
valproate is extremely mixed due to differences in
assessment tools, different populations, and varied
methodology (i.e., patients on polytherapy, blind versus
unblind, the use or lack of adequate controls). While some
research has been conducted on normal adult populations in
this area, comparable studies on children are lacking, in
part due to ethical considerations. Research on a non
epileptic pediatric group may provide the necessary data to
assess the effects of the medications in children.
Characteristics Specific to Valproate
Method of Action
The absolute method of action of valproate is
uncertain, although GABA has been the hypothesized
neurotransmitter involved. Typically given orally,
valproate is rapidly absorbed and reaches peak serum levels
approximately one to four hours after a single dose. The
serum half-life is typically 6 to 16 hours. Meals do affect
the rate of absorption, but only slightly.
While some support for GABA's involvement in valproate
exists, Johnston (1984) cites contradictory evidence. His
position on the GABA mechanism is that changes caused by
valproate cannot be attributed to an increase in the GABA
level, the potentiation of postsynaptic GABA responses, or


45
any direct membrane effect on neurons. Such an assertion
would appear to refute GABA's involvement. However, the
research on the mechanisms of valproate are far from
resolved, and the GABA hypotheses are not refuted as yet.
Animal models have shown that valproate can increase
GABA by inhibiting GABA transaminase. The significance of
this, however, is guestionable, because large
administrations of valproate (as much as 20 times a clinical
level) results in only modest and transient increases in
GABA levels (Emson, 1976). Valproate is, however,
considered to be a GABA agonist, which may affect migraine
via its influence on cerebral arteries and circadian rhythms
(Solomon, 1993). GABA dilates the cerebral arteries and may
help regulate hormone secretion from the anterior pituitary
gland.
It has also been purported that valproate has an effect
on serotonin metabolism, which would make intuitive sense
based on the potential role of serotonin in both migraine
and epilepsy (Van Woert and Hwang, 1978). In an animal
study of the effect of valproate on serotonin metabolism,
Hwang and Van Woert (1979) found that a single injection of
valproate (400 mg) decreased total serum tryptophan and
increased free serum tryptophan, brain tryptophan, and brain
5-hydroxyindoleacetic acid (5HIAA). However, they found no
effect on brain serotonin levels. They concluded that
valproate may act by displacing protein-bound serum


46
tryptophan which would result in an increase in brain
tryptophan, which would then be converted to serotonin.
In addition to proposing a mechanism for valproate and
serotonin (5-HT), Hwang and Van Woert also found differences
for various brain regions. For example, the largest effect
was a 46 percent increase in 5HIAA in the hippocampus.
Other areas showed increases as well, including the
hypothalamus, medulla, cortex, and striatum, although these
changes were not as large as that found in the hippocampus.
Despite the fact that these researchers did not report
differences in whole brain levels of 5-HT, there was a
significant increase found specifically in the striatum.
This level was elevated 113 percent over that of control
rats for this region. The overall elevated concentrations
of the various assays were attributed to increased 5-HT
synthesis. The authors suggested that the synthesis may
also be enhanced by 5-HT uptake blockade.
Using an animal model similar to that of Hwang and Van
Woert, MacMillan (1979) failed to support the hypothesis
that valproate acts to increase 5-HT synthesis. He argued
that the increase in 5HIAA was from decreased transport of
the metabolite out of the brain. An important difference
between his study and that by Hwang and Van Woert (1979) is
the lack of exploration into specific brain regions in the
MacMillan study. He acknowledged this as a potential
drawback, and it may hold the answer to the different


47
conclusions made from each study. Hwang and Van Woert
suggested that valproate may affect specific neuronal pools
(such as the striatum) that would obscure results from
studies that examined entire cortical levels of 5-HT, such
as in the MacMillan study.
Physiological Side Effects
As discussed above, valproate does not appear to have
as negative an effect on cognition as other antiepileptic
medications. However, similar to any drug, it does carry
certain risks to physiological functions. According to the
Physicians Desk Reference (PDR), valproate's most
significant physical side effect is hepatic failure.
Although not a common effect with valproate alone, signs of
sedation can be seen more commonly in conjunction with other
medications, particularly other anticonvulsants. Tremor is
a dose related side effect. More rarely, additional CNS
effects include ataxia, headache, nystagmus, diplopia, and
incoordination. It should be noted that none of these
symptoms are particularly common, and therefore do not pose
a significant threat to the child, although careful
monitoring is essential. Mattew and Ali (1991) noted that
some of the possible side effects may evidence themselves
frequently in certain subjects, such as hair loss (which
actually represents a speeding up of the normal process of
shedding of old hair), tremor, and weight gain.
Carnitine as a Supplement to Valproate Therapy


48
Research on the physiological effects of valproate have
revealed that children on such medication have significantly
lower plasma and erythrocyte free carnitine concentrations
than children on alternative antiepileptic medications
(Thom, Carter, Cole, and Stevenson, 1991). Carnitine is an
important nutrient found in the diet, plays an essential
role in the oxidation of fatty acids and in ketogenesis, and
some researchers have correlated a deficiency of this
nutrient with hepatotoxicity. Potentially toxic acyl
compounds may accumulate when the oxidation process of these
elements is impaired. Carnitine functions to regulate the
ratio of free coenzyme A (CoA) to acylcoenzyme A (acyl CoA)
in the mitochondrion (Coulter, 1991). The results from one
study indicated that free and total plasma concentrations of
carnitine decreased significantly after 15 days of valproate
administration in epileptic patients as compared to normal
controls (Riva, Albani, Gobbi, Santucci, and Baruzzi, 1993).
Murakami, Sugimoto, Nishida, Woo, Araki, and Kobayashi
(1992) showed in their research with rats that this change
in carnitine level resulting from valproate administration
could be altered to a more normal state with the concurrent
administration of carnitine. Giovannini, Agostoni, and
Salari (1991) argue that carnitine is an essential nutrient
for children, affecting multiple physiological functions
essential for development and growth. Therefore, it is


49
possible that carnitine may be supplemented for children who
are prescribed valproate to counteract such a deficiency.
Carnitine may not completely counteract the negative
effects of valproate, however. Siemes, Naue, Seidel, and
Gramm (1992) reported a case study of an infant who died
secondary to valproate complications despite the adjunctive
administration of carnitine. This finding was supported by
the research of Thurston and Hauhart (1992) who found that
carnitine administered to rats who had been given valproate
showed no effect on the reduction of free CoA and acetyl CoA
levels in the level. They found that this effect was only
achieved when carnitine was administered with pantothenic
acid. They asserted that their findings support the
hepatotoxic theory that valproate depletes CoA via
inhibition of B-oxidation and associated enzymic reactions.
Because CoA or acetyl CoA act as necessary substrates or
activators for approximately 100 synthetic and catabolic
enzyme reactions, the diverse effects of valproate can be
explained through this theory. The CoA levels are
diminished by the action of valproate, which may sequester
the substance into forms that are poorly metabolized. In
children with epilepsy, Melegh, Kerner, Acsadi, Lakatos, and
Sandor (1990) demonstrated that administration of carnitine
in conjunction with valproate over a period of 14 days did
not change the low plasma level of B-hydroxybutyrate. Total
carnitine levels were found to be lower in the children with


50
epilepsy compared to normal controls: however, this
difference was eliminated with the administration of
carnitine. Hypoketonemia was found to be carnitine
independent, though, which leaves the question of the
hepatotoxic role of valproate and the administration of
carnitine unanswered.
While research on the physiological impact of carnitine
deficiency is limited, cognitive or psychological effects of
such a deficiency in the face of valproate administration is
nonexistent. A need clearly exists for such research. One
potential reason for this lack of research is that there are
two forms of carnitine: L-carnitine and acetyl-L-carnitine.
The former is used in conjunction with valproate in some
cases to help prevent hepatotoxicity. Acetyl-L-carnitine, a
supposed cognitive enhancer, has been used in a few studies
of dementia and cognition, with its influence on the
facilitated production of acetylcholine, particularly in the
hypothalamus. Sinforiani, Iannuccelli, Mauri, Costa, Merlo,
and Bono (1990) examined the neuropsychological effects of
this form of carnitine supplement in a population of
demented patients. They found that, compared to
administration of piracetam, a neurotropic purported to
improve learning and memory, patients given acetyl-L-
carnitine showed significant improvements in attention,
comprehension ability, and specific behavioral aspects.
They also asserted that carnitine has been found to improve


51
memory impairment. Although the two forms of carnitine are
related (acetyl-CoA + carnitine acetylcarnitine + CoA) ,
they are typically used for different purposes, prohibiting
comparisons of their cognitive effects. However, Thom,
Carter, Cole, and Stevenson (1991) suggest that signs of
encephalopathy, in addition to confusion, may be a
neurologic symptom associated with severe L-carnitine
deficiency.
Studies of Valproate in the Treatment of Migraine
While valproate has not become a drug of choice for the
treatment of migraine, there is some support for its
efficacy. For example, a study by Hering and Kuritzky
(1992) to assess the efficacy of sodium valproate in the
prophylactic treatment of migraine supports the use of this
medication. They employed a double-blind randomized cross
over design with 29 adult patients. They were given either
400 mg. of valproate b.i.d. or placebo for eight weeks, then
crossed over to the other condition for another eight weeks.
Their results demonstrated that 86.2 percent of the patients
reported effective prevention of migraine or reduction of
frequency, severity, and duration of their migraines. The
drug was reportedly well tolerated (i.e., few adverse
effects). Interestingly, there was no correlation between
the effectiveness of the drug and blood levels. Also,
valproate only appeared to be effective in severe cases of
migraine. Another study (Mattew and Ali, 1991) also showed


52
a decrease in headache frequency in two-thirds of a group of
patients with intractable chronic daily headaches. They
did, however, report weight gain, tremor, hair loss, and
nausea. Neither study assessed the cognitive effects of
this treatment.
Summary
Based on the information provided in this literature
review, several conclusions become apparent. Migraine is a
phenomenon that is not uncommon in children and consequently
is receiving deserved attention from the field of medicine.
The neuropsychological and personality variables are less
well defined in this pediatric sample, allowing for further
research. Another point to be made about migraines is the
many links that have been drawn between migraine and
epilepsy. These include similarities on EEG, the presence
of aura, and familial components in some cases. An
additional intriguing similarity is the use of antiepileptic
drugs in both populations. While the use of these drugs in
the treatment of pediatric migraine has been challenged by
some, other research has shown them to be efficacious.
However, as has been shown in the epilepsy literature,
antiepileptic agents have potential drawbacks.
Phenobarbital, for example, has been shown to produce
sedative effects that may negatively impact attention and
concentration. Other drugs in this class, however, have
proved to be effective without such drastic side effects.


53
Valproate may have the least negative impact on
neuropsychological functioning, although the research on
this drug is severely lacking. One possible side effect of
valproate to be considered is that children to whom it has
been administered are at risk for carnitine deficiency and
subsequent hepatotoxicity. While the cognitive effects of
such a deficiency are not well described in children, at
least one study has shown that carnitine supplementation
improved cognitive functioning in a geriatric population.
Because most of the research in the area of cognitive
effects of antiepileptics in children has focused on
children with epilepsy, the confound arises that such a
population may have pre-existing differences in brain
functioning, and are therefore not an adequate population to
study in isolation. Migrainous children, then, are
potentially an excellent comparison group. Unfortunately,
the cognitive research on valproate and carnitine
supplementation in children is nonexistent, creating a need
for a well designed study with appropriate controls.
It would be necessary that such a study utilize
sensitive neuropsychological testing so as to describe even
the most subtle effects of both valproate and carnitine.
The questions to be answered include the following:
1. Are there any differences in personality or
neuropsychological functioning between migraineurs and
normal controls?
2. What are the cognitive effects of valproate?


54
3. What effect does carnitine supplementation have on
neuropsychological measures?


CHAPTER 2
METHODS
Subjects
Subjects were recruited from the pediatric clinic at
Shands Hospital as part of a drug study to examine the
treatment efficacy of valproate and carnitine in children
diagnosed with migraine. Accrual of subjects took place
over a 12 month period, beginning in January of 1993 and
ending in December of 1993. The mean age was 12.76 years
with a range of 9.17 to 15.83 years of age. The sample
consisted of 3 females and 11 males. An IQ screening
ensured that all subjects fell within a normal range of
intelligence (subjects with a mean scaled score below 8 or
any scaled score below 6 were excluded from the study). A
total of 14 subjects were recruited into the study and
administered baseline testing. Due to attrition, the sample
size decreased to 13 by the second testing, and to 6 by the
third testing. All subjects in the migraine group were
declared to be neurologically unimpaired by the pediatric
neurologist. EEG data for these subjects was read as
normal.
In addition to the migraine group, twenty control
subjects were recruited from area elementary and secondary
55


56
school, and a church youth group. Eighteen subjects
remained by the third testing. The age range for this group
was 7 years to 17, with a mean age of 12.08. The sample
consisted of 6 females, 14 males. There was no significant
difference in IQ between the control and migraine groups.
Materials and Apparatus
The following is a descriptive list of
neuropsychological tests used in this study:
Intellectual testing
Four subtests from the Wechsler Intelligence Scale for
Children-Revised (WISC-R) were used as an estimate of
intelligence. From the Verbal subtests, Comprehension and
Similarities both offer high split-half reliability (.77 and
.81, respectively) (Sattler, 1988). Similarities
correlates at .72 with Verbal IQ, while Comprehension
correlates .68. These particular subtests were chosen
because they offer high reliability across the age group
used in this study and are potentially less affected by
educational factors such as socioeconomic status and
educational level. Similarly, Block Design and Object
Assembly also offer good split-half reliability (.85 and
.70, respectively), and contribute information from the
Performance oriented side of the WISC-R. Block Design


57
correlates with Performance IQ .68, while Object Assembly
correlates at .60.
Together, these four subtests provided a good estimate
of IQ and served as a screening instrument, baseline, and
provided a description of the population during the initial
testing of all subjects. Because IQ was used to ensure a
normal range of intelligence for the subjects, these
subtests were administered only at baseline. The following
tests, however, were administered at each of the three
testing points.
Memory tasks
Verbal Memory
1. Buschke Selective Reminding Test (SRT): This test
of verbal memory is designed to measure verbal learning and
memory during a multiple-trial list-learning task. Each
subject was read a list of 12 words to remember, and then
was required to recall as many of the words as possible. On
subsequent trials, only words the subject failed to recall
on the previous trial were presented again. This format
offers the advantage of assessing which words are encoded
quickly (those that do not require additional prompting)
versus those that are difficult to encode. In addition, it
offers a measure of short term and long term memory, as well
as learning rate. According to Buschke and Fuld (1974),
this test maximized learning by directing the subject's
attention to those words not recalled on the previous trial.


58
Additionally, recall of an item without its presentation is
interpreted as evidence for encoding into long-term storage
(Levin, Benton, and Grossman, 1982), whereas short term
recall is reflected in items dependent on presentation.
The SRT has a number of different versions of the test,
thus making it ideal for repeat testing. Three versions
were used in this study. Clodfelter et al., (1987) state
that the different forms for children are roughly of
equivalent difficulty. Test-retest reliability is best for
the consistent retrieval aspect of the SRT at .92 (Masur et
al., 1989). Several dependent measures were obtained from
the SRT: immediate span, learning (total of items recalled
from trials 3 through 8), mean number of items recalled per
trial, and delayed recall.
2. Stories from the Wechsler Memory Scale: A modified
version of the Wechsler stories (Logical Memory Form I and
Form II) (Wechsler, 1945) was used to assess immediate and
30-minute delayed memory. There are two stories of
approximately equal length from each alternate form of the
WMS. For purposes of this study, only one of the stories
was administered at any one testing time.
Each form of the WMS contains two different stories.
Both stories from Form I ("Anna Thompson" and "American
Liner") and the first story from Form II ("Dogs of War")
were used, in the order listed here. Although the two forms
of the WMS are not identical, the Logical Memory subtests


59
are considered to be sufficiently comparable (Spreen and
Strauss, 1991) and are of similar length. Because of
extensive research on reliability and validity as well as
detailed scoring and appropriate norms (Russell Revision),
these stories are a suitable choice for this study. Raw
scores were converted to z-scores by first doubling the raw
value (because norms are based on administration of two
stories), subtracting the normative mean for the subjects
age, and dividing by the standard deviation.
3. Digit Span: In Digit Span, the subject listened to
a series of orally presented digits and then repeated them
in the same order. This measure of short-term memory and
attention has good reliability (.78), but is not predictive
of general intelligence (Sattler, 1988). It is not
significantly affected by practice, and is therefore
appropriate for multiple testing. Normative z-scores were
obtained in the same manner as described above.
Nonverbal Memory
1. Corsi Cubes: Corsi Cubes, like digit span,
reguires the subject to repeat a seguence presented by the
examiner. However, instead of verbally presented digits,
the examiner taps cubes, that are one and a half inches in
dimensions, that are randomly ordered on a board. The
subject must then tap the blocks in the same order, or in
reverse order, depending on the examiner's instructions.
Because of the absence of verbal stimuli, it is considered


60
to be a test of nonverbal memory with spatial components.
It is no more susceptible to practice effects than digit
span, and is therefore appropriate for repeated assessment.
Z-scores were obtained for forward and backward span,
providing two dependent measures.
2. Visual Learning from the Wide Range Assessment of
Memory and Learning (WRAML): The Visual Learning subtest
from the WRAML has a median reliability coefficient of .88,
while test-retest reliability is .81 (Sheslow and Adams,
1990). On this test, the child was presented with visual
designs which are arranged in particular positions on a
board. The child had to remember the spatial location of
the design, while the design is covered by sponge shields,
over a period of four trials. The color and aesthetic
qualities of this task make it ideal for children. Based on
its reliability and nonmeaningful stimuli, repeated testing
should not produce significant practice effects. A scaled
score based on the total number of correct responses was
obtained using the age-appropriate norms provided by the
WRAML manual.
Motor Tasks
1. Finger tapping: This task required subjects to
place their hand on a board with their index finger
positioned over a metal key. When depressed, this key
advances the numbers on a counter so that a tapping rate per
ten second interval may be obtained. Each hand was tested


61
on four trials each, and the rate was averaged across trials
to yield a number for each hand, which was then translated
to z-scores. Brown, Rourke, and Cicchetti (1989) conducted
research on the reliability of different neuropsychological
tests for children. Although they claimed to have found the
reliability for finger tapping to be excellent (.60) for the
dominant hand, and good (.58) for the nondominant hand,
these numbers are modestly reliable. The use of a control
group was intended to control for extraneous factors.
2. Beery Test of Visual Motor Integration (VMI); The
VMI is designed to measure perceptual-motor abilities by
requiring the subject to copy up to 24 geometric forms.
Reliabilities for the VMI range from .81 for test-retest, to
.93 for interrater reliability. Sattler (1988) comments
that the validity is satisfactory, and though the
standardization sample included 3,090 children, it is not
well defined. This test is not likely to be significantly
affected by environmental factors such as medication, and
was chosen to offer a useful comparison to other, more state
oriented measures. It was administered to subjects only at
the first and last testing. An age-based standard score was
obtained.
Attentional Tasks
1. Computerized Continuous Performance Task (CPT):
The CPT can be of two types: vigilance or reaction time.
One common reaction time format is the single-choice


62
reaction time (RT), which requires the subject to press one
of two keys immediately after cue presentation. For
example, if the letter X appears on the screen, the subject
presses a key with their left hand (such as the letter Q on
a standard key board). If the letter Y appears, they must
press a key with their right hand (such as the letter P).
The stimuli are presented at random points on the screen.
This format was used in this study to assess reaction time
changes with the administration of valproate.
The value of such a task is that some degree of speeded
decision making must take place in the context of sustained
attention in order to perform correctly. The added element
of having to choose between two responses modestly increases
the level of difficulty, therefore creating a more sensitive
test measure. In a study by Fennell, Fennell, Carter, Mings,
Klausner, and Hurst (1990), this type of task was used
effectively to show differences between a renal pediatric
population and controls. Because it is computer
administered, repeated presentations can be identical or
varied slightly (such as changing the stimulus letters) to
control for learning effects. The motor output is minimal,
leaving the effects of speeded decision making and attention
clearer.
The CPT is programmed on an IBM computer (Fennell, et
al., 1990). For purposes of this study, the program was run
on either a Leading Edge portable computer to accommodate


63
change in testing site, or a standard IBM computer. The
task was a simple-choice reaction time in which the subject
had to respond to the letter X by pressing the Q key on a
keyboard, and to the letter Y by pressing the P key on the
keyboard. The letters were presented singly (i.e., one X or
one Y) at random spatial locations on the screen, at random
intervals. The intertrial intervals alternated between 2,
5, and 8 seconds. Exposure time alternated between .3, .6,
and .9 seconds. Each of the 108 trials was repeated twice
for a total of 216 presentations. Correct responses were
those where both of each repeated trials were responded to
correctly. Mean reaction time across all trial pairs and
conditions served as the primary dependent measure for this
task. No normative data is available for this task,
necessitating the use of covariate statistics in analysis.
2. Paced Auditory Serial Addition Test (PASAT): The
PASAT is a serial addition task typically presented via
audio tape. This method of administration controls for rate
of presentation and difficulty level, which can be 2.4, 2.0,
1.6, or 1.2 seconds per digit, with a total of 61 digits per
trial. The subject is required to listen to a series of
digits and, upon hearing the second, add it to the first,
then adding the second to the third number, and so forth.
For example, upon hearing "3, 7", the subject should answer
"10". If the next digit is "5", the subject should arrive
at "12", by adding 7 and 5.


64
This test reportedly is a sensitive measure of
information processing and sustained attention (Gronwall and
Wrightson, 1981). Gronwall and Sampson (1974) describe the
PASAT as a test that assesses some central information
processing capacity analogous to that seen on reaction time
and divided attention tasks. Because of its difficulty and
attentional demands, it is an ideal test to measure subtle
changes in the ability to process information at a given
rate.
One drawback to the PASAT is the evidence of
significant practice effects (Gronwall, 1977). However,
after the second presentation, these practice effects are
not a factor as performance does not continue to improve at
such a rate. For the second presentation, though, a control
group is requisite to compare practice effects and tease out
their impact versus the impact of medication. Spreen and
Strauss (1991) report excellent split-half reliability (.96)
for this measure.
Subjects were administered the 2.4 and 2.0 second
interval trials. A total of 49 correct responses for each
of the two conditions was possible. Normative data allowed
for z-score transformation.
Parent Report
Child Behavior Checklist CBCL): A commonly used
parent report child assessment tool is the Child Behavior
Checklist (Achenbach & Edelbrock, 1986). The CBCL can be


65
self-administered to the child's parent or guardian. The
CBCL provides separate norms for 3 age groups: 4 to 5, 6 to
11, and 12 to 16 by sex. There are subscales within each
age group, as well as the two broad-band factors of
Internalizing and Externalizing. Children who rate as
externalizers may be seen as more overactive and as
possessing more conduct problems than those who rate as
internalizers. Factor loadings from the narrow-band scales
justified the labels "Interalizing" and "Externalizing.
The CBCL is very well standardized and has adequate
reliability and validity. It is reported by DuPaul et al.
(1991) to be the best standardized rating scale in use.
Due to the number of variables and relatively small
sample size, the data from the CBCL was summarized into an
Internalizing score and an Externalizing score (both scaled
as t-scores). A third variable was a simple bipolar
assignment which was made for each subject according to
whether they did or did not have any scale scores that were
in a clinically significant range (i.e., > 70).
Procedures
A screening battery was administered to all subjects
prior to their introduction to medication. This battery
included all test instruments listed above, including the IQ
screen and parent report measures. In the second and third
testings, however, IQ was omitted, and the CBCL and VMI were
omitted from the second testing. Following baseline


66
testing, all migraine subjects were then given valproate for
the period of four weeks, after which they were retested to
assess any changes in neuropsychological functioning as a
result of the valproate. Valproate dosage was established
according to weight of the subject, and was titrated
according to blood levels (goal therapeutic range was 50 to
100 ml). Following the second assessment, subjects were
randomly assigned to one of three groups: 1) Group 1
continued on valproate and also receive carnitine; 2) Group
2 continued on valproate and received a carnitine placebo;
and 3) Group 3 received placebos for both valproate and
carnitine, and was therefore drug free. Subjects remained
in their respective groups for a period of 8 weeks, after
which they were tested for a third and final time (see
Figure 1).
Test order was constant across testings. For the
initial testing, the IQ screening will be administered,
followed by a 10 minute break. During this break, the
subtests were scored to determine if the subject met the
minimum criterion for admission to the study. This break
also served to minimize any fatigue effects of the IQ screen
before the actual test battery was administered. The
remaining tests were given in the following order: WMS
story (immediate), CPT, PASAT, WMS story (delay), Finger
Tapping, SRT learning trials, Visual Learning (WRAML), Digit
Span, Corsi Cubes, SRT delay, Visual Learning delay, and VMI


67
(the VMI only on first and third testings). The CBCL was
completed concurrently during the first and third testings.
During the initial four week period when all subjects
were taking valproate, only the subjects were blind.
However, when the subjects were randomized into one of three
groups, both subjects and experimenters were blind to
condition.
Hypotheses
(1) There will be no significant differences on
neuropsychological tests between the migraine children and
the control group at baseline.
(2) Parent report (CBCL) will reveal subtle
differences on scales such as somatic complaints and
anxiety. This difference is not likely to be significant
given the effect and sample size.
(3) Following one month of valproate therapy, the
experimental group will perform worse than the nonmigraine
control group on neuropsychological tests that are most
sensitive. Attention oriented tasks (CPT reaction time and
the PASAT) and memory (verbal and nonverbal) tasks will be
the most likely to reveal differences between the groups.
(4) After dividing the experimental group into three
subgroups, the group who is receiving carnitine supplement
will perform better on sensitive neuropsychological tests
than those who are not receiving the supplement, although
this difference may not be statistically significant.


68
However, there will be a significant difference in
performance such that the third group (those on valproate
placebo and carnitine placebo) will show significantly
better performance than the other two groups. This implies
that valproate will have the most negative impact on
cognitive functioning. Finally, none of the experimental
groups will perform better than the nonmigraine control
group.
(5) After receiving treatment for their migraines,
there will be a decrease in parent report of behavioral
problems, such as anxiety or somatic complaints.


69
TABLE 2-1
SUBJECT CHARACTERISTICS
MIGRAINEURS
CONTROLS
Mean Age
12.8 (2.2)
12.1 (3.
Age Range
9-15.8
7-17
Female/Male Ratio
IQ subtest means
3/11
6/14
Similarities
11.4 (2.2)
12.3 (3.
Comprehension
10.2 (2.2)
13.1 (2.
Block Design
9.2 (2.6)
11.1 (2.
Object Assembly
10.4 (4.0)
11.5 (3.
Number of Subjects
at baseline
14
20
NOTE: Standard deviations are provided in parentheses.


CHAPTER 3
RESULTS
There was no significant overall group effect for IQ.
All subjects were considered to be within a normal range of
intelligence.
Descriptive statistics were conducted for both groups
at baseline. Table 3-1 provides the means and standard
deviations for both groups separately and as a whole for all
variables used at baseline. Table 3-2 provides the same
statistics for scores at the second testing.
The first hypothesis for this study was that children
with migraine would not differ from the control group at
baseline measurement. To assess the validity of this
hypothesis, a multivariate analysis of variance (MANOVA) was
conducted on the domain scores for each subject at baseline
to determine if there was any significant difference between
migraineurs in an unmedicated condition and controls.
Specifically, items related to verbal memory constituted one
domain and was analyzed together, as were nonverbal memory
items. Domains analyzed were as follows: Verbal Memory
(Logical Memory and the Buschke SRT), Nonverbal Memory
(Visual Learning from the WRAML), Memory Span (Digit Span
and Corsi Blocks), Attention (PASAT and the CPT reaction
70


71
time), Visual-Motor (VMI), and Behavior (CBCL). By grouping
the variables into MANOVAs as described, the number of
statistical analyses was reduced in an attempt to control
for a Type I error. For the Attention domain, a MANCOVA
(multivariate analysis of covariance) with age as the
covariate was reguired because of a lack of normative data
for the CPT. The study by Fennell, et al. (1990)
demonstrated that there were age effects for reaction time,
such that reaction time decreased as age increased. The use
of a MANCOVA was intended to take this age effect into
account for these analyses.
At initial testing, no significant differences were
seen between the migraine and control groups on any of the
neuropsychological tests. A t-test to assess any
differences on the VMI approached significance (p = .052),
with the migraineurs reflecting a lower mean score for the
VMI than the control group.
The second hypothesis was that the parents of
migrainous children would endorse more problem behaviors,
particularly those considered to be a reflection of somatic
complaints, than parents of the control children. Scores
from the CBCL were summarized into t-scores for
externalizing and internalizing factors. The mean


72
internalizing score for the migraine group was 61.85, and
the mean for the externalizing score was 55.08. Because too
few parents returned the CBCL for the control group, the
migraine group scores were compared to the published
normative data using a Welch's T-test. For the normative
data, mean scores are 50 with a standard deviation of 10.
Using this method, a significant difference resulted for the
internalizing factor (p < .05) but not for the externalizing
factor. The mean number of clinically elevated scales for
the migraine group at baseline testing was 2, with a range
of 0 to 9. The most commonly elevated scale was Somatic
Complaints.
The third hypothesis tested was that subjects taking
valproate after one month would perform significantly worse
on measures of memory and attention than the non-medicated
control group. A repeated measures MANOVA was conducted for
each domain for the first and second testings to assess the
effect of introducing valproate to the migraine group.
Results from this set of analyses resulted in no significant
group effect for any of the neuropsychological domains
measured. The repeated measures MANOVA for Span was the
only domain analysis that approached significance (F = 2.46,
p = .069).
After examining the blood levels of valproate for the
migraine group, it was apparent that many of the subjects
were not in a therapeutic range (i.e., 50 or higher).


73
Therefore, another set of repeated measures MANOVAs was
performed with different groupings. Because there were no
significant differences observed at baseline between the
migraineurs and controls, those migraineurs who were not
considered to have a therapeutic blood level of valproate
were re-assigned as controls for this analysis. Therefore,
the groupings resulted in those migraineurs with a
therapeutic blood level of valproate versus all other
subjects. The results from this analysis yielded a
significant group by time interaction on only the Attention
domain (F = 5.06, p = .036). This was actually a repeated
measures MANCOVA, with age as the covariate due to a lack of
age norms for the CPT reaction time data. The results
indicate that group membership and time of testing (i.e.,
after one month of valproate therapy) were important
variables on the Attention domain.
Difference scores were obtained between the variables
on testing one and two, and a correlation analysis was
conducted on these difference scores and the blood levels
obtained at the second testing. This analysis therefore
includes only migraineurs. Although none of the
correlations obtained were statistically significant,
several did approach significance. Both the fast and slow
trials of the PASAT were close to significance (p = .083 and
p = .058, respectively), but in opposite directions. The
fast trial of the PASAT revealed a positive correlation


74
while the slow trial revealed a negative correlation. The
immediate recall of Logical Memory also neared significance
(p = .064, positive correlation), as did Visual Learning
from the WRAML (p = .062, negative correlation). These may
have reached significance with a larger sample (total sample
size for these correlational analyses ranged from 11 to 13).
The fourth hypothesis involved data from the third
testing, after migraine subjects were randomly assigned to
one of three groups (valproate plus carnitine, valproate
plus placebo, and placebo plus placebo). The results from
the third testing were unable to undergo statistical
analysis because of a high attrition rate resulting in an
extremely small sample with group sizes of one to three
subjects. Correlations between blood level and the third
testing did not result in any significant relationships,
perhaps due to the even smaller sample size.
The fourth hypothesis also predicted that carnitine
would improve cognitive functioning in those subjects
receiving valproate, but this difference would not be
statistically significant. This could not be analyzed due
to the severe attrition. Additionally, there was no
eguivalent check for compliance as there was for the
valproate as measured by blood level. Therefore, even those
subjects assigned to take carnitine were not clearly under
the influence of the supplement.


75
The fifth hypothesis was that migraineurs would show
improvement by the third testing with the administration of
valproate on parent report of problem behaviors. The CBCL
data was analyzed for the seven subjects remaining at the
third testing. Neither the internalizing or externalizing
scores differed significantly from the normative data.
Although this is consistent with the hypothesis, the
internalizing score remained higher than the externalizing
score (64.29 compared to 59.14), indicating that problems
behaviors in this domain were still perceived by parents to
be more problematic than the externalizing behaviors.
Failure to reach significance is probably due to sample
size, given that the means are slightly higher than at
baseline. The increase in means from baseline to third
testing is likely a result of differential attrition, but
this was also not significant. Also, not all subjects were
in a therapeutic range of valproate because of group
membership and due to compliance issues.
Post-hoc Analyses
A significant practice or test order effect (F = 7.85,
p = .01) was observed for all subjects for the Visual
Learning test that comprised the Nonverbal memory domain, as
well as Logical Memory (p = .000).
A Chi-Square was performed to determine if group
membership among the migraineurs (i.e., placebo versus drug
conditions) predicted attrition. From the valproate plus


76
carnitine group, 75 percent dropped out, while 57 percent
attritted from the valproate plus placebo group, and 25
percent attritted from the placebo plus placebo group.
Although these numbers appear to be significant, Chi-Square
analysis did not support this (p = .35). This lack of
statistical finding may also be due to a relatively small
sample size.
A test of binomial proportion was conducted on two
groups (the two groups administered valproate were collapsed
into one group and compared to the placebo plus placebo
group). The corresponding rates of attrition for the groups
were 70 percent for the valproate group, and 25 percent for
the placebo group. This approached significance (p = .062).
To determine if adolescents were more likely to be
noncompliant than children, the migraineurs were divided
into two groups: those 13 and older, and those 12 and
younger. A t-test based on these two groups and comparing
the mean blood levels after one month of valproate therapy
resulted in a significant finding (p = .002), such that
adolescents had a lower mean blood level. Among the seven
adolescents in this analysis, five had blood levels that
were not in a therapeutic range (i.e., less than 50). All
of the children (ages 12 or younger) had blood levels over
50.
Finally, to determine if compliance was related to
socioeconomic status, the subjects were divided into those


77
that were labelled medically needy and receiving aid from
Children's Medical Services, and those who had private
insurance coverage. This did not result in a significant
difference in blood level between the two groups.


78
Table 3-1
Means and Standard Deviations for Migraine and Control Group
at Baseline
All Migraineurs Controls
(The following group means are based on scaled scores)
Visual
Learning
10.2
(2.66)
9.5
(2.20)
10.7
(2.90)
(The following
group
means
are based on z-scores)
Logical Memory
(immediate)
Logical Memory
.84
(1.66)
.74
(1.98)
.93
(1.35)
(delay)
.92
(1.51)
1.10
(1.79)
.75
(1.21)
Digits Forward
-.69
( -61)
-.94
( -39)
-.50
( -68)
Digits Backward -.67
( -53)
-.60
( -42)
-.72
( -61)
Corsi Forward
-.54
( -54)
-.74
( -57)
-.38
( -54)
Corsi Backward
.37
( -62)
.48
( -66)
.30
( -60)
PASAT Slow
-.82
(1.26)
-1.27
(1.43)
-.43
( -98)
PASAT Fast
-.77
( -97)
-1.10
( -98)
-.49
( -89)
Motor Tapping
-.32
(1.02)
-.26
(1.24)
-.36
( -87)
CPT Reaction
Time
40.19
(9.20)
41.64
(10.0)
39.2
(8.81)
VMI Standard
Score
99.10
(9.52)
94.38
(6.80)
102.0
(10.0)
CBCL Intern.
T-score
61.85
(9.95)*
CBCL Extern.
T-score
55.08
(11.8)*
* The migraine group was compared to the published normative
data for these measures. Therefore, no means are listed for
the control group.


79
Table 3-2
Means and Standard Deviations for Migraine and Control Group
at Second Testing
All Migraineurs Controls
(The following
group
means
are based
on scaled scores)
Visual
Learning
11.55
(3.25)
10.92
(3.45)
11.95
(3.14)
(The following
group
means
are based
on z-scores)
Logical Memory
(immediate)
-.63
(1.40)
-.83
(1.72)
-.50
(1.17)
Logical Memory
(delay)
-.58
(1.39)
-.81
(1.74)
-.41
(1.13)
Digits Forward
-.60
( .65)
-.97
( -38)
-.37
( -68)
Digits Backward -.38
( -72)
-.32
( -93)
-.42
( -56)
Corsi Forward
-.21
( .65)
-.40
( -58)
-.08
( -68)
Corsi Backward
.49
( -68)
.40
( .47)
.55
( -79)
PASAT Slow
-1.24
(1.25)
-1.83
(1.26)
-.82
(1.09)
PASAT Fast
-1.04
( -96)
-1.46
( -81)
-.74
( -97)
Motor Tapping
. 32
(1.16)
. 12
(1.03)
.43
(1.23)
CPT Reaction
Time
47.94
(14.9)
50.44
(21.5)
47.0
(12.7)
(The following
scores
were
obtained
from the third
testing)
VMI Standard
Score
106.2
(10.7)
102.20
(13.8)
107.4
(9.77)
CBCL Intern.
T-score
64.29
(12.5)*
CBCL Extern.
T-score
59.14
(14.24)*
* The migraine group was compared to the published normative
data for these measures. Therefore, no means are listed for
the control group.


CHAPTER 4
DISCUSSION
The literature is represented by heterogeneous results in
the studies of both migraine and valproate. The underlying
mechanisms of both continue to be disputed. In addition to
the discrepant findings on the neuropsychological effects of
migraine in adults, the introduction of childhood and
adolescent migraine further clouds the picture. Several
authors have claimed to have found neuropsychological
differences between adult migraineurs and controls (e.g.,
Kohler & Fennell, 1992; Crisp, Levett, Davies, & Rose, 1989;
and Hooker & Raskin, 1986), while others assert that no
differences exist (e.g., Leijdekkers, et al., 1990; Burker,
Hannay, & Halsey, 1989). Their discrepant findings may be the
result of a number of different factors, including
inappropriate statistics conducted on relatively small sample
sizes, leading to spurious results. Other factors may include
the use of cognitive tests that paint the neuropsychological
picture in broad strokes rather than using more sensitive
measures that target subtle cognitive changes. Additionally,
the ages of the subjects and migraine history may play a key
role in the findings. Regardless of the adult studies on
migraine and cognitive functioning, there remains to be
80


81
addressed the question of cognitive differences in children or
adolescents with migraine. They may comprise a different
subset of migraineurs due to the necessarily different history
of the migraine process.
The debate over the neuropsychological impact of
antiepileptic medications has also yet to be resolved. Older,
supposedly more detrimental medications such as phenobarbital
have been examined in several studies and their cognitive
impact has been described. However, the effects of valproate
remains controversial regarding whether patients receiving the
medication suffer a compromise in certain aspects of
neuropsychological functioning. One problem in assessing this
medication is the population used to test its effects.
Historically, adults or children with epilepsy have been a
favored sample on which to demonstrate the effects of
valproate, among other similar medications. The results have
been mixed with this method (e.g., Aman, Werry, Paxton, &
Turbott, 1987; Bittencourt, Mader, Bigarella, & Doro, 1992;
Blennow, Heijbel, Sandstedt, & Tonnby, 1990) and the methods
employed have included both the administration of valproate in
polytherapy, and the withdrawal of medication in presumably
stable epilepsy patients. The drawbacks to this population
are obvious: epilepsy patients may have poorer
neuropsychological performance due to the epilepsy rather than
to the medication. It is unethical to place a patient with
epilepsy in a placebo control group, therefore making the


82
distinction between the epilepsy and drug effect uncertain.
Withdrawal studies also due not control longer lasting effects
of medications well, although blood levels may control for
some of this effect.
Additional studies of the effects of valproate have
included normal adult volunteers to assess the effects of the
medication (e.g., Harding, Alford, & Powell, 1985; Thompson &
Trimble, 1981). This method is also not without its
drawbacks, however. Most studies of this type only administer
the medication for short periods of time, often without a
blood level check to ensure therapeutic levels. The few
studies of this type are also plagued with methodological
problems such as poor assessment of neuropsychological
abilities and inappropriate statistical procedures. Although
this method may prove beneficial under the appropriate
conditions, to date these results have not yielded
substantial, useful information. Additionally, it is a method
that would preclude the use of normal children in most cases,
therefore omitting important data regarding this potentially
different group.
Several studies have documented the efficacy of valproate
as a prophylactic medication for migraine (e.g., Sorensen,
1988; Hering & Kuritzky, 1992) This provides another
population useful for studying the cognitive effects of the
medication, particularly in children. Although some studies
have determined that migrainous individuals may have some


83
different neuropsychological deficits, this has yet to be
demonstrated in children. If in fact, migrainous children are
not significantly different on cognitive measures that other
children without medical compromise, then they would provide
an excellent opportunity to assess more pure effects of
valproate.
Interpretation of Findings
Several important findings result from the current study.
First, no significant differences were found on baseline
testing measures between the migraine group and the control
group. This study is one of the first to examine the
potential for neuropsychological differences in an adolescent
migraine group. Results suggest that there are no
neuropsychological differences between children and
adolescents with migraine and a similar group of controls.
One exception to this is the difference between groups on the
VMI (p = .052). Although this finding suggests differences in
visual motor integration, this finding was not apparent at the
third testing, perhaps due to the decreased sample size.
Overall, the finding of no difference at baseline (unmedicated
state) is in contrast to a few of the adult studies that have
found differences on cognitive measures. One potential reason
for this is differences in methodology and statistical
procedures. Another interpretation, however, is that a
fundamental difference exists between adults and children with
migraine. Some have suggested that migraine, like epilepsy,


84
compromises the brain through repeated vascular attacks
(Farkas, Kohlheb, Benninger, & Matthis, 1992; Levitn,
Malvea, & Graham, 1974; Eviatar, 1981) that may have long
term, permanent effects. Therefore, patients with a longer
history of migraine would be more likely to exhibit cognitive
impairments. Children and adolescents with migraine, however,
may not have the extended history of migraine necessary to
demonstrate such impairments. Additionally, the fact that
children are less likely to be diagnosed with classic migraine
than adults may also play a role in the cognitive differences
between these populations.
Despite a lack of differences found on neuropsychological
measures, migraineurs did demonstrate higher internalizing
problem scores on the CBCL than is expected from the general
population. Externalizing behaviors were not reported as
being significantly different. These results are not
surprising given the frequency of scale elevations for Somatic
Complaints, which contains report of headache. However,
several subjects had more than one scale elevation, which may
reflect personality differences in adolescents with migraine
versus their headache-free peers. This is consistent with the
research on adult migraine (e.g., Leijdekkers, et al., 1990;
Burker, Hannay, & Halsey, 1989) that has supported differences
in personality even without evidence of neuropsychological
differences. Research examining personality characteristics
of adolescent migraineurs (e.g., Andrasik, et al.,
1988;


85
Cooper, et al., 1987) has found higher reports of depression
(which is considered to be an internalizing behavior on the
CBCL), among other behaviors, and supports the findings from
this study.
Analyses conducted on the first and second testings
indicated that valproate has little effect on most
neuropsychological domains with the exception of attention.
This finding was only borne out when the subjects were re
grouped according to therapeutic blood level, which lends
further support to the finding that migraine group membership
alone does not reveal differences. It may be that the
measures of attention used in this study are more sensitive to
subtle alterations in functioning caused by valproate than the
other measures. Attention itself may be more sensitive to
external factors than memory, although greater degrees of
impairment in attention are likely to have a negative effect
on memory. The findings by Hwang and Van Woert (1979) that
valproate has a greater effect on striatal and hippocampal
areas of the brain supports the differences found in attention
in this study because of striatal connections with frontal
lobe structures, but does not explain the apparent lack of
results regarding memory. Again, varying degrees of test
sensitivity may be the cause.
Unfortunately, the original design intended could not be
analyzed due to the degree of attrition. The third testing
was originally intended to measure the effects of valproate


86
with placebo controls in a double-blind manner, as well as the
concurrent administration of carnitine. With only three
subjects remaining that were taking the carnitine supplement,
statistical analysis was impossible. Additionally, these
subjects demonstrated a level of noncompliance with the
valproate that could be measured with blood levels, but this
method was not possible with carnitine. Therefore, of the
three subjects assigned to carnitine, all or none of them
could have actually been taking the supplement. Analysis,
even qualitative, would be rendered meaningless. Although not
significant, a greater number of subjects in the valproate
plus carnitine group dropped from the study, with the
valproate plus placebo group comprising the next largest group
of drop-outs, followed by the placebo plus placebo group. The
negative side effects of the medication may have been the
cause of this differential attrition, as well as the aversive
taste of the carnitine (one subject confided that he was not
taking the carnitine for this reason).
Adolescent Noncompliance
Because compliance was such a significant factor in this
study, this topic deserves further discussion. The literature
on compliance in adolescents and children has increased
significantly over the past two decades. In an extensive
review of the compliance literature, Dunbar-Jacob, Dunning,
and Dwyer (1993) noted that 91 studies were conducted in this
area between 1970 to 1989, with research ranging from simple


87
assessment of compliance to intervention or treatment designed
to increase compliance. However, of the 91 studies conducted
during this time span, none included specific assessment of
the compliance of migrainous adolescents. Also, a search for
research employing such a population between 1989 and 1993 was
unsuccessful. Despite the lack of research on a migrainous
population, the results of numerous other studies on
compliance in adolescents are helpful in attempting to
understand better the underlying causes of the low compliance
in this study.
The literature on childhood compliance in general reveals
dramatically poor adherence to medication regimens, even with
potentially life-threatening illnesses such as cancer. This
low level of compliance has been shown to be worse for
adolescents compared to younger children (e.g., Tebbi, 1993;
Johnson, 1993). In a study specifically designed to assess
the level of compliance in adolescent patients with acute
lymphoblastic leukemia or Hodgkin disease, 52 percent of the
patients were noncompliant with their prednisone therapy,
while nonadherence was demonstrated in 48 percent of those
prescribed penicillin for post-splenectomy prophylaxis. These
findings are not unusual, which is demonstrated by the
findings of Ettenger et al. (1991). They found a medication
noncompliance rate of 50 percent in 70 pediatric renal
transplant patients. The rate was slightly higher for


88
adolescents (64 percent). Unfortunately, the result of this
noncompliance was a 13 percent loss of transplant graft.
Given that the literature has supported the belief that
adolescents generally demonstrate poor compliance with medical
regimens, the focus then should be on what factors contribute
to poor compliance and how compliance might be improved among
this group. Brooks-Gunn (1993) detailed several
biopsychosocial risk factors influencing adolescent health
behavior. One of these factors is the cultural context in
which the adolescent is embedded. Different cultural views on
medical adherence and the locus of responsibility (i.e., who
is responsible for the administration of medications) can
impact the level of compliance achieved in a given population.
In addition to cultural factors, individual factors also play
a significant role. These include biological (e.g., hormonal
changes and levels of depression), emotional, and social-
cognitive (e.g., perceived costs and benefits, risks, and
future consequences) factors. These issues are particularly
relevant in the adolescent population who are often seen as
being naive to consequences of risky behavior. Environmental
factors may also play a role in compliance, particularly via
the influence from peers and parents. As children enter
adolescence, conformity becomes increasingly important.
Perceived differences between the patient and peers based on
medication usage and side-effects may contribute to
noncompliance. An important variable is the parental


89
influence, which may become less as the adolescent becomes
increasingly independent. In fact, it has been stated that
parents themselves become less compliant with medical regimens
as their children enter adolescence (S. B. Johnson, personal
communication). A final environmental factor is that of the
physician/patient communication. The patient may feel that
they are being compliant, but due to poor communication, they
may actually have gaps in their knowledge about the medication
or treatment plan that leads to inadvertent noncompliance
(Johnson, 1993). This is most likely to be problematic for
younger children, but can also be seen in adolescents.
In a study of the psychosocial determinants of compliance
in adolescents with iron deficiency, Cromer, Steinberg,
Thornton, and Shannon (1989) reported a 67 percent compliance
rate. Factors they found to be statistically significant
predictors of compliance included side effects of the
medication and freguency of family reminders to take the
medication. This suggests that, even with adolescents,
instruction to the parents to become more involved in their
children's medical adherence may be beneficial. Also, the
report that negative side-effects tended to decrease
compliance is consistent with the descriptive results from
this study, in which several patients complained of negative
side-effects.
The concordance of parent and adolescent views on
medication has been explored in at least two studies. Tebbi,


90
Zevon, Richards, and Cummings (1989) measured cancer patients
and their parents on attributions related to their degree of
perceived responsibility. These authors failed to demonstrate
a relationship between parent-child concordant attributions
and medical compliance. However, in an earlier study, Tebbi
et al. (1988) did find that compliance was greater when
parents and patients agreed on who was responsible for
administration of the medication and their understanding of
instructions and effectiveness of the medication. This would
theoretically alter the diffusion of responsibility (which
would likely reduce adherence) by placing the responsibility
on one individual. However, even in such a model, parental
support would likely benefit the adolescent.
Noncompliance has also been associated with a restriction
of the adolescent's independence, low self-esteem, and poor
family relations (Friedman, 1986). One method of increasing
compliance, therefore, would appear to be increasing self
esteem and perceived independence, as well as clarifying to
both the parent and adolescent who is primarily responsible
for the administration of the medication. This is consistent
with the research of Tebbi et al. (1988). Weinberger (1987)
noted that compliance can also be enhanced by including the
patient in decision making in order to foster an internal
locus of control. These suggestions appear to be relatively
simple methods of improving compliance among adolescents.
Assigning a health paraprofessional or research coordinator to


91
assess compliance throughout a study, improve communication,
and offer reinforcement for adherence, may also be beneficial.
The level of noncompliance in this study is probably
multi-factorial. The fact that adolescents were significantly
less compliant than the children is consistent with the
literature. Also, the majority of compliance research has
focused on children and adolescents with potentially fatal
illnesses such as cancer. The fact that the subjects in this
study were being treated for a relatively benign, although
aversive, problem (i.e., migraine) may have led to even lower
compliance rates. Typically, headache pain is treated by the
sufferer on an as-needed basis with over the counter
medications. Therefore, the idea of long term daily use of a
medication that has potential side effects may have also
contributed to low adherence. Finally, the chaotic nature of
many of the families in the study may have created
difficulties for the patients in their ability to maintain a
consistent schedule of administration. The incentive to
change their migraine situation compared to the negative
aspects of consistent medication may have not been great
enough to lead to good adherence.
The literature on adolescent and childhood compliance is
helpful in taking steps to increase compliance for treatment
and research purposes. In retrospect, several steps could
have been taken to reduce the level of attrition and improve
the value of the study. Closer follow-up with each of the


92
subjects and their parents, both in clinic and via telephone,
could have served to help the subjects feel more engaged in
the study, and to address any concerns they may have had at
any point. Through frequent contact and better education
about the medication and its side effects, the subjects and
parents may have been less likely to drop out and instead
communicated any problems they were having. This follow-up
was attempted at a lesser level, with reminders for
appointments being made by telephone, but failed to address
the broader issue of communication. Diffusion of
responsibility was also problematic in this study. Those that
created the study were not always the ones in direct contact
with the subjects, and therefore not responsible for follow
up. Others that had more contact, did not feel responsible
for conducting the follow-up either, resulting in a gap of
service. Assigning one individual specifically to conduct the
follow-up would have lessened the diffusion of responsibility,
and perhaps reduced attrition. Part of the follow-up and
original education could have been designed to engage the
parent in the study, particularly for adolescent subjects.
The issue of diffusion of responsibility most likely operated
at this level as well, with parents and adolescents feeling as
if someone else was responsible for their adherence. By
engaging the parents early in the study, this issue could have
been clarified with the families, with specific
responsibilities assigned to both adolescent and parent.


93
A methodological change could also have helped circumvent
the attrition issue. Most of the attrition occurred after the
randomization of subjects into three groups, after the month
of valproate treatment. A better design may have been to
randomize the subjects immediately after baseline testing,
thereby obtaining data from more subjects after only one
month, rather than three months when many had dropped-out.
This would provide a placebo control group as well as
carnitine data that was not available in this study. A cross
over could then occur after one month to obtain a cleaner
picture of valproate's effects. This methodological change
would not, however, remove the compliance problem as it
applies to drug level. This compliance may have been improved
by the methods described above, as well as employing more
frequent blood level checks and appropriate follow-up.
A final method of minimizing attrition is by making the
entire study less aversive. Reducing the amount of time the
subjects had to spend per visit, either by waiting for their
appointment or the time spent in the neuropsychological
testing, may have made subjects less likely to drop-out of the
study. Providing them with an incentive (e.g., monetary) may
also have helped reduce the aversive nature of the study and
decreased attrition.
Limitations of the Study
As has been alluded to above, the level of attrition in
this study created statistical problems that precluded testing


Full Text

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81,9(56,7< 2) )/25,'A


UNIVERSITY ,OF FLORID^
3 1262 085 57 0595


THE NEUROPSYCHOLOGICAL EFFECTS OF VALPROATE WITH AND
WITHOUT CARNITINE SUPPLEMENT IN A PEDIATRIC MIGRAINE SAMPLE
By
KRISTIN M. FIANO
A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
1994

ACKNOWLEDGEMENTS
The amount of time and effort required to conduct a study
and compile a document of this magnatude is enormous and could
not have been done without the exhaustive efforts of many
people. The author would like to extend her sincerest
gratitude to the members of her committee who ensured that
this effort was not wasted. They have provided candid,
constructive feedback at every point and are congratulated on
their superb work as committe members. Special thanks go to
a non-committee member, Paul Kubilis of Biostatistics, for his
consultation.
The author would also like to make a special
acknowledgement to her committee chairperson, Eileen Fennell,
who has filled many roles throughout the past five years. She
has served as advisor, mentor, and friend, and has left a
lasting impression on the author and her future work. Her
care and expertise are deeply appreciated.
Finally, personal appreciation is extended to family
members, particularly the author's husband Ric Fiano, who
prevented the world from falling apart on several occassions,
and to Edward and Patricia Galloway, the author's parents,
whose love and pride finally paid off.
11

TABLE OF CONTENTS
page
ACKNOWLEDGEMENTS ii
ABSTRACT iv
CHAPTERS
1 INTRODUCTION 1
2 METHODS 55
Subjects 55
Materials and Apparatus 56
Procedures 65
Hypotheses 67
3 RESULTS 70
4 DISCUSSION 80
Interpretation of Findings 83
Adolescent Noncompliance 86
Limitations of Study 93
Conclusions 97
REFERENCES 100
BIOGRAPHICAL SKETCH 108
iii

Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
THE NEUROPSYCHOLOGICAL EFFECTS OF VALPROATE WITH AND
WITHOUT CARNITINE SUPPLEMENT IN A PEDIATRIC MIGRAINE SAMPLE
By
KRISTIN M. FIANO
August 1994
Chair: Eileen B. Fennell
Major Department: Clinical and Health Psychology
Adult studies of patients with migraine suggest that some
patients have difficulties in verbal memory and attention.
Little valid research has been conducted in this area on a
pediatric sample. This study assessed the presence of
neuropsychological differences in children with migraine
compared to normals, and the effect of a medication used in
the treatment of migraine.
Whether an antiepileptic drug used for the prophylaxis of
migraine has a detrimental effect on neuropsychological
processes is also an area of controversy. Valproate, used in
this study, has historically been purported to exert fewer
negative side-effects on cognition than other antiepileptic
medications, (e.g., phenobarbital). However, such research
has primarily used epilepsy patients, thus confounding the
effect of diagnosis with drug effect. The purpose of this
iv

study was to assess the cognitive effects of valproate in
children without a diagnosis of epilepsy.
Fifteen patients recruited from the pediatric clinic at
Shands Hospital were enrolled in the study. Twenty control
subjects, similar in age and gender distribution, were
recruited from a local school associated with the University
of Florida and from a local church group. All subjects were
administered a neuropsychological battery at three testing
points. At baseline, intellectual screening was used to
assure a normal range of IQ. Measures included verbal memory,
nonverbal memory, memory span, attention, motor tapping, and
parent reports of problem behavior. Migraine subjects
received valproate monotherapy for one month after baseline
testing before their second testing. Subjects were then
divided into valproate plus carnitine supplement, valproate
plus placebo, and placebo plus placebo groups, for an
additional eight weeks. A third testing was administered at
that time. Control subjects were administered the same tests
in the same manner, but without treatment.
Children and adolescents with migraine were not found to
differ from normals at baseline. Once migraine therapy was
initiated, modest declines in attentional functioning were
observed but problems with attention did not impact memory.
v

Another finding was the significantly higher rate of
internalizing problem behaviors among the children with
migraine, which is consistent with some findings in the adult
migraine literature. Limitations and further interpretations
are discussed.
vi

CHAPTER 1
INTRODUCTION
Headaches in the general population are quite common
and, due to an estimated 150 million lost workdays, can pose
problems for the work force in this country. Approximately
90 percent of the United States population are affected by
headache, with as many as 45 million forced to contend with
headache pain (Silberstein, 1991). While headache pain for
many people is often tension related, others experience
headaches associated with the phenomenon of migraine. This
subset of headache may also have stress as a trigger, but
the mechanism is thought to be different than in the common
tension headache, and has an added hereditary component.
Historically, adults are the first to be eligible for
newly emerging medical techniques or to be the focus of
research. Gradually, however, more research is being
dedicated to these problems in children. Although children
do not readily come to mind when discussing tension
headaches or migraine, they do in fact represent a
substantial percentage of the general population affected by
such a condition (Fenichel, 1985). As a result, migraine
headaches in children have received increasing attention
from medical services over the past several decades, and
1

2
this trend is continuing among several health related
professions, including clinical psychology.
Definition and Classification of Migraine
Migraine headache is defined by a list of symptoms.
Sacks (1992) notes that headache is never the sole feature
of a migraine nor is it considered to be essential. Several
requisite features have been identified, including the
presence of periodic or recurrent headache, nausea, and
family history. Other symptoms that may co-exist but that
are not essential for diagnosis include the presence of
neurological symptoms (paresthesia, scotomata), or aura
(Bille, 1962; Rossi, 1989). Unilateral symptoms are common
and serve as a good marker for migraine in adults. These
will be discussed in further detail below.
The International Headache Society classifies headaches
into four broad categories, the first of which is migraine.
Subtypes of migraine in this classification scheme include
those without aura, with aura, ophthalmoplegic and retinal
migraine. The three remaining broad categories in this
system are tension-type headaches, cluster headaches, and
miscellaneous headaches not associated with structural
lesion. It should be noted, however, that this
classification system is designed for the adult population,
and has not been accepted for use in children.
Within the diagnosis of migraine, two common
classifications may be identified: classic and common

3
migraine. They are distinguished by the presence or absence
of aura. Rossi (1989) suggests that classic migraine, or
migraine with aura, is most likely on the same continuum as
common migraine, which is without aura. She proposes that
they differ more in the frequency rather than the quality of
the symptoms, and therefore should be considered as two
manifestations of one syndrome. Sacks (1992) identifies the
cardinal symptoms of common migraine to be headache and
nausea, while the classic migraine is characterized by aura.
Fenichel (1985) describes five broad groups of migraine
that differ slightly from those listed by the International
Headache Society. In addition to cluster headaches, and
classic and common migraine, they include basilar migraine
and migraine equivalents. Classic migraine may be
subdivided further into several categories, some which will
be mentioned briefly. Patients exhibiting focal motor
deficits, such as hemiplegia or ophthalmoplegia, can be
classified into a subgroup termed complicated migraine.
A common method of classifying migraine was provided by
Peroutka (1992). His list of subtypes and associated
symptoms is recreated in Table 1-1. Of interest is the
emphasis placed on the unilateral or contralateral
components of each migraine subtype. Again, however, this
system does not completely reflect migraine in children, as
they are more likely to exhibit bilateral than unilateral
headaches. A more important symptom in children is the

4
pulsatile nature of the headache. An interesting aspect
regarding the laterality of migraine is Wolff's (1963)
report that right-sided headaches are most common in right¬
handers .
Table 1-1
Classification of Migraine
Types of Migraine Symptoms
1. Common
2. Classic
3. Complicated
Hemiplegic
4. Ophthalmoplegic
5. Basilar Artery
Unilateral (80%)
throbbing headache with
associated nausea
Same as common migraine but
preceded by a visual aura
Sudden onset of hemiparesis
followed by a contralateral
throbbing headache
Unilateral eye pain and
ipsilateral ophthalmoplegia
Visual aura with alterations
in consciousness prior to
headache
Source: S. J. Peroutka (1992). Migraine. in M. V.
Johnston, R. L. MacDonald, and A. B. Young (Ed.) Principles
of Drug Therapy in Neurology. Page 162.
These neurologic symptoms associated with migraine are
most commonly transient, resolving within 24 hours. Rarely,
though, they may leave permanent neurologic deficits that
can be guite subtle, diagnosed only with sensitive
neuropsychological test measures. Brown (1977) comments

5
that there is still doubt as to whether recurrent mild
ischemia can result in lasting brain-damage, with subsequent
dementia and cerebral atrophy. However, Cole and Aube
(1990) reported three well-documented cases of migraine that
were associated with intracerebral hemorrhage. Each of
these adult cases showed spasm of the external or internal
carotid artery. They concluded that "vasospasm associated
with severe migraine attacks may result in ischemia of the
intracranial vessel walls, leading to necrosis and
subsequent vessel rupture when perfusion pressure is
restored" (page 47) .
Additional Symptoms
Although not specific to children, less frequent
symptoms may be present in a child diagnosed with migraines
in addition to those described above. While migraine is
often eased by sleep (Rossi, 1989), it may be worse in the
morning. This may raise the suspicion of increased
intracranial pressure effects. Rossi reports other, less
frequent symptoms that include paresthesia, a "march" of one
to thirty minute duration that progresses from upper limb to
face, and from distal to proximal. She also reports cases
of dysarthria or aphasia, or an acute confusional state
lasting anywhere from hours to days.
Additionally, in the acute phase of an attack, migraine
patients may show nystagmus, presumably due to
vertibrobasilar ischemia. Vertigo may also be a symptom

6
present in classical migraine or basilar migraine (Brown,
1977). Brown also reports that pectoralgia, or constricting
chest pain, may be an accompanying symptom of migraine.
The most common migraine symptoms associated with aura
are visual. These visual aberrations may include
experiences such as transitory blindness, sparkling lights,
micropsia, macropsia, or even visual hallucinations. Brown
(1977) describes many of these deviations that can range
from a simple blurring of the vision, to visual field cuts,
to complete transitory blindness. Colored lights in various
shapes may also be seen. Brown reports that hallucinations
of mice or butterflies, or an entire scene breaking from
reality, are not rare. Ophthalmoplegic pain and paralysis
of eye movement, while suspicious symptoms, may also
accompany migraine. Additional common symptoms are the
nausea and vomiting which often accompany a migraine attack.
This is sometimes referred to as "abdominal aura," and may
occur for a long period of time before the onset of actual
migraine symptoms (Brown, 1977).
Finally, another group of symptoms consist of brainstem
dysfunction, commonly referred to as the basilar artery
migraine syndrome. Patients with this subgroup of migraine
may exhibit ataxia, visual aura or even loss of vision,
vertigo, tinnitus, alternating hemiparesis, and parasthesias
of the fingers, toes, and corners of the mouth (Fenichel,
1985). Brief alteration in consciousness may also result.

7
Testing performed on children with basilar migraine has
shown an abnormal caloric response (nystagmus induced by the
introduction of cold or warm water to the ear canal)
(Eviatar, 1981). Others have shown an association with
epilepsy in this group, exemplified by spike wave forms on
EEG, recurrent seizures, and partial complex symptomatology
(Panayiotopoulos, 1980). Interestingly, antiepileptic
therapy yielded relief of migraine in this group of
patients. Fenichel (1985) asserts, however, that in the
absence of associated seizure activity, antiepileptics are
of no proven value in treating these children. As will be
seen, Fenichel's belief is challenged by current medical
research.
Pathogenesis
If one is to group both classical and common migraine
together as elements of the same syndrome, then a singular
cause must be identified. Three prominent theories of
migraine pathogenesis will be presented here, as well as
other, more comprehensive, theories:
1. Vascular dvsrequlation: A common hypothesis
proposed by Wolff (1963) and also held by Rossi (1989) is
that vascular dysregulation underlies both types of
migraine. Wolff (1963) conducted experiments and
observations that indicated a vasoconstrictive and
vasodilative phase, which distinguish the prodrome and
headache phase. Fenichel (1985) describes these same two

8
vascular phases of migraine. The first, which takes place
in the preheadache stage, consists of vasoconstriction,
during which cerebral blood flow decreases. This is most
strongly associated with the internal carotid system in
classic migraine. Symptoms associated with this phase
include the visual aberrations described above (or "migraine
equivalents"), which are the most common form of aura. The
second phase, which is associated with the headache, is
vasodilation, and involves the external carotid system.
Patients describe headaches during this phase as throbbing,
pulsating, or pounding, a characteristic of the vasodilative
phase. This second phase is also distinguished by the
concomitant symptoms of migraine such as nausea or vomiting.
Welch, Spira and Lance (in Diamond, Dalessio, Graham and
Medina, 1975) have shown that a single agent (such as
prostaglandin-e) can create these differential effects in
blood flow in external (carotid dilation) and internal
(redistribution of flow) vasculature.
While this theory of migraine has support from
research, others (Sacks, 1992) claim that it is far too
simplistic in and of itself to explain fully the
multitudinous aspects of migraine. The vascular components
of the migraine process may, therefore, be only another
aspect of migraine rather than an adequate explanation.
Other, more elaborate theories therefore exist in an attempt

9
to offer a better understanding of the entire process of
migraine.
2. Serotonergic abnormalities; A second theory,
originated by Sicuteri (1961), arose from the finding that
plasma concentrations of serotonin decline at the appearance
of a migraine attack and remain significantly depressed
throughout the duration of the episode (e.g., Curran,
Hinterberger, and Lance, 1965; Hilton and Cummings, 1972, as
cited in Fenichel, 1985). In contrast, serotonin levels
rise during the migraine aura (Peroutka, 1992). This is
consistent with the evidence that serotonin applies a
powerful constrictor effect on extracranial vessels (Rigg,
1975; Sicuteri, Testi, and Anselmi, 1961). Current
hypotheses involving serotonin suggest that prophylactic
antimigraine medications function by blocking specific
serotonin receptor subtypes, whereas abortive drugs
stimulate these receptors. This may be too simplistic,
however, and, as will be discussed, the difference between
abortive and prophylactic medications may also be affected
by their action on different 5-HT receptor subtypes.
Further research has shown that the platelets of
migraineurs are different from those of nonmigraineurs in
their serotonin-releasing effect. Fenichel (1985) goes so
far as to say that migraine may primarily be a platelet
disorder, and daily aspirin may therefore act
prophylactically. The role of serotonin in migraine is

10
still unclear, but evidence supports at least partial
involvement of this neurotransmitter. Some authors (Sacks,
1992) report that one common symptom of migraine is
depression. This side effect is consistent with a serotonin
hypothesis given that serotonin is thought to play a strong
role in depression as well. Whatever the actual mechanism,
there is strong support for a serotonin hypothesis that is
based upon pharmacological evidence which has shown that
various medications that operate via serotonin can either
cause or terminate a headache episode (Diamond, Dalessio,
Graham, and Medina, 1975).
3. Spreading Depression of Leao: Finally, a
phenomenon known as the spreading depression of Leao has
been used to explain migraine pathogenesis. This electrical
phenomenon occurs in response to noxious stimulation
(Peroutka, 1992), and may be initiated by vasoconstriction
(Fenichel, 1985). This activity originates in the occipital
cortex, which may explain the predominantly visual aura.
The oligemia slows at the Rolandic and Sylvian fissures, but
may eventually reach the frontal cortex via the insula
(Fenichel, 1985). Its arrival at the sensorimotor cortex
occurs during the headache phase after the prodrome,
supporting the role of spreading depression in migraine.
In addition to the above hypotheses, the
trigeminovascular system also plays an important role in

11
migraine. Because it provides the primary afferent pathway
for head pain (Peroutka, 1992), this system has been
included in many theories of migraine pathogenesis. Neurons
in the peripheral unmyelinated fibers of the
trigeminovascular system contain substance P. This
neurotransmitter is known to be involved in several
functions: dilation of pial arteries, increase of vascular
permeability, and activation of cells involved in the
inflammatory response. This last function has an apparent
influence on head pain that can occur in the absence of
obvious external precipitating factors. According to
Peroutka (1992), the hypothesized action of the
trigeminovascular system and substance P may explain the
fact that the majority of migraines are unilateral. In
addition, the pain in migraine is referred to areas
innervated by the trigeminal nerve. Finally, the aura most
commonly associated with migraine is a result of "posterior
circulation dysfunction", this posterior area being densely
innervated by the first division of the trigeminal nerve.
Solomon's (1993) model of migraine incorporates several
concepts, some of which are common to the above mentioned
theories. First, he suggests that the trigeminovascular
system serves the purpose of protecting the brain, just as
other pain systems work to protect other parts of the body
by signaling problems, which, in this case, would include
ischemia or toxins. The trigeminal nerve can be stimulated

12
by both electrical (neuronal) and chemical factors. The
chemical factors would include neurotransmitters, such as
serotonin, and may work directly (hormones affecting
prostaglandins) or indirectly (e.g., REM sleep reducing
serotonin release from the dorsal raphe nucleus). This
latter mechanism may help explain why sleep often eliminates
the migraine in many patients. Whatever the trigger, the
stimulation may result in a release of tachykinins from the
trigeminal nerve, such as substance P, into the meningeal
and dural blood vessels. This results in the release of
histamine, vasodilation, and the platelet release of
serotonin. The release of substance P results in
inflammation and blood vessel swelling. Finally, this
swelling and inflammation causes distention of the cranial
arteries and the headache pain.
Solomon's model has the appeal of explaining many of
the components known about migraine, including a role of
serotonin, the cause of the actual headache pain, the
benefit of antihistamines, the purpose of sleep to alleviate
the migraine, and the possible mechanisms of numerous
triggers. The pain involved in migraine may be caused by
local inflammation and sensitization of nociceptors by
substance P. In any case, this model emphasizes the
importance of an ischemic or neurochemical noxious trigger
that stimulates the trigeminal nerve. This model does not

13
exclude other theoretical perspectives, but may instead help
to link them together in a more comprehensive model.
A more functional model of migraine was proposed by
Crisp, Levett, Davies, Rose, and Coltheart (1989). They
conducted a study on 57 migrainous adult patients, 26 of
whom had classic migraine with primarily unilateral
prodromata. Among these subjects, all were right handed,
and 19 had left hemisphere prodromata. One had right
hemisphere prodromata, but had a history of only one
migraine. Others were indeterminate or bilateral. The
findings indicated that unilateral classical migraine
categorized according to prodromal clinical characteristics
in right-handed people is exclusively a left (dominant)
hemisphere phenomenon. These researchers suggested that
this type of migraine was a result of a relative dysfunction
of the ipsilateral hemisphere, rendering it susceptible to
overload of information to be processed. In this case, left
hemispheric prodromata would be due to dysfunction in the
properties of the left hemisphere, such as verbal
processing. Although Crisp et al. did find some support for
their hypothesis, their interpretation may very well be
incorrect. That is, if an individual experiences a long
history of unilateral migraine (their subjects' mean length
of migraine history was nine years), then the processes
involved, such as those described by other theorists above,
may result in a compromise of the systems of that particular

14
hemisphere. Additionally, the stimuli that these
researchers used to measure spatial ability had qualities of
verbal processing and attentional demands rather than being
a relatively pure measure of spatial processing.
Nevertheless, the finding that right handers with unilateral
migraine have a strong tendency towards left hemisphere
involvement as measured by prodromata is intriguing. These
researchers screened out left handers for purposes of their
research, but reported that of the five subjects they found
with right hemisphere unilateral migraine, all five were
left handers. Although these researchers assessed numerous
patients with unilateral pain, persistent unilateral pain
may suggest other factors, such as arteriovenous
malformations.
Demographic Variables
Prevalence
Although there are discrepancies, most place the
prevalence of childhood migraines at approximately four
percent (Bille, 1962). There is evidence that migraine has
a hereditary component, which is presumed to be autosomal
dominant, according to Fenichel (1985). Brown (1977) states
that as many as 90 percent of migraine cases have a family
history, also suggesting autosomal dominance. Fenichel
(1985) purports that the prevalence of migraine is 2.5
percent in children under 7, which then rises to 5 percent

15
in children past that age. In the older age group, females
are slightly over represented at a 3:2 ratio.
Outcome
According to Fenichel (1985), the frequency and
intensity of migraine tends to decrease with age. However,
some studies have shown that, as a group, children with
migraine die at younger ages than nonmigraineurs (Levitón,
Malvea, and Graham, 1974). Also, presumably due to the
vascular mechanisms involved, this group has a higher risk
for stroke, especially in women taking oral contraceptives
(Fenichel, 1985).
Personality Differences
There have been several studies exploring personality
characteristics in children with migraines. Brown (1977)
asserts that, contrary to earlier beliefs, migraine is not
associated with high intelligence. Common findings from
more personality oriented investigations describe migraine
children as dejected, depressed, or withdrawn, with the
potential for becoming stubborn, inflexible, argumentative,
and rebellious (Wolff, 1963). Wolff also reported that
memory and attention can be impaired during the headache.
Bille (1962) has described these children as being more
anxious, fearful, and nervous than their same aged peers
without headaches. Most of the earliest studies employed
nonstandardized questionnaires or simply clinical impression
(e.g., Menkes, 1974). As a result, findings were mixed and

16
yielded little useful data. Others have attempted to avoid
such problems through the use of standardized instruments
and appropriate control groups.
Andrasik, Kabela, Quinn, Attanasio, Blanchard, and
Rosenblum (1988) conducted a study to examine the
personality characteristics of two groups of children with
migraines. An older, adolescent group consisted of subjects
between the age of 13 and 17, while the ages of children in
the younger group ranged from 8 to 12. All subjects were
age matched with controls. The measures utilized in this
study were primarily parent report and self-report
questionnaires. Findings from this study were that headache
sufferers earned significantly higher scores on measures of
depression from several scales, and expressed a higher
number of somatic complaints, even with the omission of
headache related questions. Andrasik et al. also found
that, overall, the adolescent group was less successful in
coping with their migraines than the younger group. They
hypothesized that adolescents, while trying to develop their
independence, at the same time had unpredictable migraine
attacks that often ruined social plans. This
unpredictability may therefore create a need to be dependent
on a caretaker or foster feelings of anxiety. Andrasik et
al. found that this pattern was particularly true for males,
and suggested that, because of accepted roles for males and
the expression of their pain or discomfort (which does not

17
include crying or openly admitting pain), male adolescents
had to find alternative methods of expressing their pain.
This often came in the form of externalizing behaviors or
moodiness.
In contrast to these findings, Cooper, Bawden,
Camfield, and Camfield (1987) found from their study of
children with migraine, that such children do not report a
higher number of life stressors than their best friends
without migraine. This was found despite the fact that the
children with headaches and their parents both reported that
stress is the most common trigger of migraine attacks.
Cooper et al. (1987) do agree with Andrasik et al. in the
finding by parent and self-report measures, that migraine
children have significantly higher ratings on scales such as
somatic concerns and depression. Andrasik et al. (1988)
suggest that migraine children do not experience greater
life stress (based on questionnaire) than normals, which
would suggest the differences in somatic concerns and
depression are related to the migraine rather than the
migraine resulting from stress. Furthermore, despite no
significant difference between the headache and control
groups on stress or anxiety, Cooper et al. (1987) did
provide evidence suggesting that the most anxious children
in their sample had the most frequent and severe headaches.
They concluded that stress and anxiety exacerbate migraines

18
in children who have inherited the migraine tendency, rather
than being a direct cause of migraine.
Neuropsychological Differences
A recent paper by Kohler and Fennell (1992) examined
the differences in performance on neuropsychological tests
between adult migraine patients and normal controls. The
results of this study suggested that migraineurs perform
significantly worse on verbal and nonverbal memory tasks
than age matched controls. This difference was largely
attributed to the common migraine group, as there was no
significant difference between the classic migraineurs and
controls. No groups showed differences on learning tasks.
These researchers hypothesized that those migraineurs with
aura (i.e., classic migraine) may be able to cope better
with an impending migraine attack due to the benefit of a
warning sign, which would enable them to use medications
that may prevent the headache phase of the migraine.
Presumably, those patients who experience fewer headaches
may therefore be at a lower risk for ensuing ischemic damage
that could negatively impact memory functions.
Neuropsychological studies of patients with migraine,
however, have yielded mixed results. A study by
Leijdekkers, Passchier, Goudswaard, Menges, and Orlebeke
(1990) compared the neuropsychological performance of 37
adult female migraineurs with that of 34 nonheadache female
controls. They employed a variety of tests, including

19
measures of verbal learning, short term memory, reaction
time, sustained attention, and motor tapping. They did not
find significant differences on any of their measures of
cognitive functioning, nor did they reveal any effects of
migraine history or medication use. Further dividing the
migraine subjects into classical versus common also did not
result in group differences. They did, however, note higher
trait and state anxiety levels, state depression, and less
vigor, based on self-report measures, in the patient group
compared to the control group.
Yet another set of findings by Hooker and Raskin (1986)
provides evidence for a different interpretation of the
question of neuropsychological differences in migraineurs.
They administered a battery of tests including motor tests,
verbal and nonverbal memory tests from the Wechsler Memory
Scale, Trail Making Test, the Wisconsin Card Sorting Test,
and the Tactual Performance Test (TPT). Thirty-one migraine
subjects and 15 controls were used in this study, with a
combination of males and females. The authors found that
subjects with classic migraine exhibited decreased upper
extremity motor speed and dexterity, less efficient learning
of new associations between dissimilar symbols, and
dysphasic errors. Combining the classic and common migraine
subtypes into one group revealed poorer delayed free recall
for verbal material and decreased performance on the TPT.
These researchers argued that the classic migraineurs

20
demonstrated a larger scope of functional compromise than
the common migraineurs, and suggested therefore that the
classic form of migraine reflects a primary disturbance of
the central nervous system. Their findings are in direct
contrast to the study by Kohler and Fennell (1992), which
indicated that the common migraineurs experienced greater
neuropsychological impairment. Hooker and Raskin (1986)
also showed that no single class of drug showed differential
impact on the Halstead-Reitan Average Impairment Index,
which is consistent with the findings by Leijdekkers, et al.
(1990).
In another study, Ai (1992) administered a
neuropsychological test battery to 48 migraineurs, 20
patients with functional headache, and 20 controls. The
primary result was that migraineurs had higher dysfunction
in the areas of motor, perception, memory, abstract thought,
attention, and information processing. Additionally, the
dysfunction was worse with a longer course of migraine.
Crisp, Levett, Davies, Rose, and Coltheart (1989)
demonstrated in their study of 57 male and female patients
that migraineurs as a group (i.e., classic and common
migraine) exhibited poorer verbal and spatial performance
than controls.
Despite the evidence resulting from these studies that
true differences do exist between migraineurs and matched
controls, another study provides evidence that there are no

21
significant differences. Burker, Hannay, and Halsey (1989)
examined 47 migrainous female college students and 24
controls. No significant differences were found on the
Halstead Reitan Neuropsychological Test Battery and other
memory tests. Like Leijdekkers et al. (1990), however, they
did observe personality differences as measured by the
Minnesota Multiphasic Personality Inventory (MMPI) on
Hysteria and Paranoia scales between classic and common
migraineurs, and differences on the Hypochondriasis and
Hysteria scales between all migraineurs and controls.
It is unclear what factors are contributing to these
divergent findings. One possibility is that many of the
findings by Hooker and Raskin (1986) are spurious, resulting
from the numerous statistical analyses they conducted on a
relatively small sample size. Kohler and Fennell (1992)
employed age and sex-standardized scores in a multivariate
analysis which limited the number of tests of significance
and controlled for the correlation between measures.
Leijdekkers et al. (1990) attempted to use relatively basic
behavioral tests rather than more complex tests, which they
felt would be overly sensitive to extraneous influences and
lead to spurious results. This may also have served to mask
real differences between the patient and control groups.
The diverse collection of research in this area does
not appear to support strongly any one hypothesis.
Different test batteries, methods of analysis, or individual

22
differences may all contribute to the inconsistencies
reported here. Additionally, these studies were conducted
on adult patients, which may be a vastly different
population than migrainous children, in part because of the
longer history of a potentially damaging process in the
adults. Also, children are less commonly diagnosed with
classic migraine. This dimension has been significant in at
least several studies and may lead to different findings for
an adolescent population. Unfortunately, no comparable
research base exists to date on children with migraine.
Imaging Techniques and Coincidence with Epilepsy
Some investigators assert that the use of EEG, cranial
computed tomography (CT), or other types of brain imaging
techniques, constitutes an excess in diagnostic procedure
with migrainous children (Prensky and Sommer, 1979).
Others, however, declare that such diagnostic tools have
value in the research and assessment of migraine. For
example, Alvarez-Cermeno, Gobernado, Freije, Zaragoza, and
Gimeno (1984), reported two cases of pediatric migraine
which showed CT contrast enhancement in the occipital
region. They stated that although these areas were poorly
defined, the important finding was that the CT changes were
evident only during the active phase of migraine.
Regional Cerebral Blood Flow (rCBF) has also been
examined in children with migraine. Roach and Stump (1989)
concluded that regional reduction in the expected blood flow

23
surge after C02 inhalation was a frequent finding, lending
support to the already strong belief that pediatric migraine
is a disorder of vasomotor function. However, others argue
that there may be no change in cerebral blood flow in
migraine without aura (Silberstein, 1991). In a study on
adults with migraine, Thie, Carvajal-Lizano, Schlichting,
Spitzer, and Kunze (1992) attempted to measure cerebral
vasoreactivity (CVR) via trascranial Doppler ultrasound
(TCD) during cognitive and motor tasks. They imaged the
left middle cerebral artery (MCA) and left posterior
cerebral artery (PCA) and compared CVR in migraineurs to
controls. Although they found that migraineurs as a group
had higher mean flow velocities for photic stimulation,
observation of complex images (both PCA measures), and the
cognitive task (MCA measure), they cautioned against any
strong conclusions. They stated that individual differences
were too great to allow this form of imaging to be a
sufficiently sensitive measure of migrainous activity.
Migraine is not an uncommon associate of epilepsy,
particularly when the migraine is associated with an aura
(De Romanis, Buzzi, Feliciani, Assenza, and Agnoli, 1991).
Fenichel (1985) asserts that familial epilepsy syndromes and
migraine are associated for the following reasons:
(1) they are both familial, paroxysmal, and associated
with transitory neurologic disturbances;
(2) there is an increased incidence of epilepsy in
migraineurs and migraine in epileptics;
(3) headache can be a seizure manifestation; and

24
(4) abnormal electroencephalograms are common in both
disorders, (p. 80)
The mere presence of a correlation, however, does not
confirm that epilepsy and migraine are biologically linked.
Furthermore, abnormal EEGs are not indicative of any
specific disorder, as some portion of the normal population
shows evidence of abnormal electroencephalographic activity.
Other similarities exist, however. It may be that
repeated migraine creates compromised tissue that could
result in epileptic discharges. Also, when a child has
symptoms of confusion, personality change, rage reactions,
and hallucinations, they may mimic the symptoms of a partial
complex seizure. Furthermore, the flicker-rate of scotomata
in migraine is of the same frequency of the stroboscopic
illumination that is most likely to cause epileptic seizure
(Sacks, 1992). Jackson (1931, as cited in Sacks, 1992)
asserted that migraines were in fact cases of epilepsy of a
sensory nature, with the headache and vomiting representing
the post-paroxysmal period. Other evidence does lend
support to the correlation between epilepsy and migraine,
although the precise relationship is unknown.
EEG recordings between migraine attacks may reveal
sharp or spike waves from the temporal-occipital or
temporal-parietal regions, and reflect clinically reported
symptoms from children with migraine. These children often
report visual hallucinations, hemianopsia, or amaurosis in

25
conjunction with migraine attacks (De Romanis et al., 1991),
which is consistent with photophobia reported in migraine
sufferers without epilepsy. In many cases, migraine is seen
in combination with epilepsy such that an attack may be part
of the prodromal phase of the epileptic event, but there may
also be a dissociation between migraine and epilepsy such
that the migraines continue years following the resolution
of the seizure disorder.
Because the occipital EEG wave pattern is so common in
childhood migraine headaches (e.g., De Romanis et al.,
1991), it may be that even in the absence of clinically
evident seizure behavior, subclinical abnormal activity is
responsible for migraines. Why the posterior cortical areas
are more susceptible to such activity may be due to a
neuronal sensitivity in the occipital region (De Romanis et
al., 1991). This, in conjunction with the fact that visual
patterns may trigger migraine as well as epilepsy (Brown,
1977), lends support to a relationship between the two
syndromes. In fact, Sacks (1992) considers migraine to be
on the "borderland" with epilepsy and other neurological
disorders, suggesting that they share similar symptomatology
and possibly similar underlying mechanisms. He suggests
that the paroxysm in migraine can be 20 times slower than in
the epileptic counterpart.
Additional evidence from EEG data on migrainous
children reveals no difference between these children and

26
age-matched controls between headaches. However, Seri,
Cerquiglini, and Guidetti (1993) found that during visual
aura a decrease in occipital alpha power contralateral to
the affected hemifield was evident in all migraine patients.
Furthermore, this was followed by an increase in delta power
in the bilateral frontal regions. During the headache, an
increased delta activity in posterior-temporal and occipital
electrode sites was also shown. The involvement of
occipital areas, especially during visual aura, is
consistent with neuroanatomy. The bilateral frontal
involvement, however, may reflect neuropsychological
impairment, probably quite subtle, that may include problems
with attention. Whether such an impairment could be
measured between events remains to be seen. Such
differences in EEG background activity (slowing) has been
observed between migraineurs, idiopathic epilepsy patients,
and controls, with no significant difference within the two
patient groups (Farkas, Kohlheb, Benninger, and Matthis,
(1992) .
Like migraine, epilepsy may manifest with the
predominant associated feature of abdominal pain, sometimes
termed "abdominal epilepsy". The differentiation between
abdominal migraine and abdominal epilepsy is not entirely
clear cut on the basis of subsequent convulsions or EEG
(Brown, 1977). Prensky (1976) reports that children with

27
abdominal pain as their major symptom seem to have more
epileptiform EEG changes that those with simple migraines.
Treatment
Behavioral
The most common factor implicated in triggering a
migraine is psychological stress (Rossi, 1989) or emotional
tension (Brown, 1977). In pediatric cases, the frequency of
migraine is much higher during the school year than in the
summer, also implicating psychological stressors. This
finding suggests that an ideal treatment for migraines is
behavioral.
Behavioral approaches to the treatment of pediatric
migraine consist primarily of biofeedback, which can be
defined simply as bringing those bodily processes that are
normally involuntary and unconscious under voluntary control
(Gascon, 1984). This often requires the use of electronics
that have the capability of translating biological signals
(e.g., vasodilation) into signals that can easily be
detected (e.g., auditory signal). One method of biofeedback
is EMG, which is commonly used to assess frontalis muscle
activity, typically in tension headaches. For migraine,
however, temperature biofeedback is commonly employed as a
behavioral technique designed to influence vasoconstrictive
processes. While many of the treatment studies conducted in
adults have not yielded strong findings (Gascon, 1984),
children may be more promising candidates for this type of

28
treatment. Womack, Smith and Chen (1988) report that
children naturally like the use of imagery and biofeedback,
and are often enthusiastic about the procedures. Gascon
(1984) has suggested that children learn biofeedback
techniques more quickly than adults, and that if effective,
such a treatment option has obvious desirability. Brown
(1977) recommends that regular drug therapy be reserved for
only the most severe cases. While medications are still
most common, behavioral approaches offer treatment that
allow the child to feel more in control of their migraines,
as well as to avoid the problems of drug side effects.
In a study conducted by Womack, et al., (1988),
children were asked to keep diaries of their headaches.
They then participated in biofeedback (EMG and/or skin
temperature for most subjects), as well as relaxation and
mental imagery. After eight weekly sessions and 12 month
follow-up, results showed that, of 29 subjects, 48 percent
of the migrainous patients were headache-free, and an
additional 41 percent showed a greater than 50 percent
reduction in headache frequency. Eighty-six percent showed
a decrease of over 50 percent in perceived intensity.
Despite the fact that Womack et al. did not employ a control
group, these findings are encouraging. Many factors may
have been involved, however, such as the simple act of
monitoring the pattern of headaches through the use of a
diary, or even a treatment placebo effect, and the

29
investigators made no attempt to tease out possible
differential effects. Also, since migraine headaches may be
erratic in their pattern of occurrence, some changes may
have been attributable to normal variations in occurrence.
Additionally, the short duration of the study may not be
sufficient to determine if there was an actual change or a
temporary placebo effect. Also, each subject received a
combination of treatments (imagery, relaxation, and
biofeedback). This would make it difficult to determine
what aspects of treatment, if any, played a significant
role. Despite the shortcomings of the study, the authors
conclude that behavioral treatment has a high probability of
improving headache condition in children and adolescents.
Guarnieri and Blanchard (1990) attempted to assess the
effectiveness of biofeedback in a clinic treated group
versus a home practice group. They claim to have found a
clinically significant reduction of headache frequency and
intensity, though these numbers did not reach statistical
significance. There was no significant difference between
the two groups on measures of expectation or symptom
improvement, suggesting that home treatment is equally
effective. Burke and Andrasik (1989) found similar results,
adding that the gains made by their subjects were stable,
maintained through a one-year follow-up period. Finally,
Smith, Womack, and Chen (1989) found no correlation between
age, sex, headache type, hypnotizability, and clinical

30
outcome. Most recently, these findings were strengthened by
the similar results of McGrath, Humphreys, Keene, Goodman,
Lascelles, Cunningham, and Firestone (1992) who showed that
self-administered behavioral treatment was effective with
adolescents, even at a one year follow-up. An adult follow¬
up study on the long term effects of training in relaxation
and stress coping was conducted by Sorbi, Tellegen, and Du
Long (1988). They found that the positive results from
behavioral and cognitive treatments were still in effect
after a period of three years.
Diet
Some researchers have considered allergies and diet as
possible triggers for migraine attacks (Brown, 1977),
including foods rich in tyramine or phenylethylamine.
Consequently, a modified diet has been attempted in the
treatment of migraine. Specifically, tyramine, which is
known to release serotonin from platelets, has been reduced
in diets for clinical treatment, or added to the diets of
controls to precipitate migraine experimentally. This
relationship has yet to be firmly established.
Medication
Some common medications used in the treatment of
migraine headaches in children include propranolol,
ergotamine tartrate, pizotifen, cyproheptadine, and calcium
channel-blocking agents (Rossi, 1989). Some of these (e.g.,
ergot derivative) are most effective when administered

31
during the aura, if present, prior to the onset of the
actual migraine. Fenichel (1985) suggests the use of two
medications, ergotamine and isometheptene mucate, for the
acute treatment of migraine. For ergotamine, the chief
mechanism of operation is constriction of the extracranial
blood vessels. The latter drug, isometheptene mucate or
Midrin, is a sympathomimetic agent which constricts
extracranial veins, and has been shown by a few studies to
be at least as effective, if not more, than ergotamine.
Brown (1977) suggests that ergotamine will ease headache of
common migraine, but may actually aggravate the ischemic
neurological abnormalities of complicated migraines.
For migraine prophylaxis, Fenichel (1985) lists many
drug classes, including serotonin agonists and antagonists,
antidepressants, antihistamines, vasoconstrictors,
vasodilators, tranquilizers, calcium-blocking agents, and
antiepileptics. Solomon (1993) states that prophylactic
medication operating via serotonin are specific to 5-HT2
receptors. Antagonists "are able to inhibit serotonin from
inducing an arachidonic acid-derived inflammatory state."
(p. 202). This explains why such a medication can operate
only prophylactically, because once the inflammation has
been initiated, the 5-HT2 antagonist would be useless.
Gascon (1984) also lists antiepileptic drugs as being
among the group of effective medications for migraine, and
asserts that these drugs are most effective in preadolescent

32
children. Phenobarbital, phenytoin, carbamazepine, and
valproic acid are among the many antiepileptic drugs used
for this purpose. Moreover, there is no clear indication
that associated epileptiform activity is necessary for the
effective use of antiepileptics in children with migraine.
The mechanism in which antiepileptic drugs affect migraine
is yet to be discovered, and to date, there is a surprising
lack of well conducted studies (e.g., prospective, double
blind, placebo controlled) in this area. However, according
to Solomon (1993), the action of these medications, at least
that of valproate, would operate at the level of 5-HT2
receptor site in order either to prevent serotonin-induced
cerebral vasospasm and ischemia, which may activate the
trigeminal nerve, or by inhibiting the arachidonic acid
metabolism as described above.
Sorensen (1988) conducted a prospective study of the
efficacy of valproate in 22 adult patients with severe
headache resistent to previous prophylactic treatment.
Subjects were followed over an average of six and a half
months to assess the efficacy of the medication. Eleven
patients were free from migraine, 6 demonstrated a
significant reduction in freguency, and one had no change.
Four of the patients withdrew from the study because they
could not tolerate the withdrawal of their previous
medication (injected narcotic). Sorensen also attempted a
withdrawal of the valproate for four weeks with three

33
patients who were free from the attacks. In all three
patients, their headaches recurred, but subsequent
administration of valproate again caused the disappearance
of the headaches. Side effects noted included drowsiness in
one patient and slight weight gain in three females, and two
patients reported severe cold painful paresthesias of the
extremities only during the first days of treatment.
Unfortunately, a placebo effect cannot be ruled out in this
study because no control group was used and patients and
experimenters were unblinded. However, because these
patients had previously tried numerous medications without
apparent relief, it is not likely that these results are
solely due to a placebo effect.
Cognitive Effects of Anticonvulsant Medication
Despite the number of studies conducted for the purpose
of examining the differential cognitive or
neuropsychological effects of antiepileptic medication, very
few have employed good experimental methods such as double¬
blind designs, adequate control groups, or appropriate
neuropsychological tests. Therefore, a need remains for
solid research to determine the extent to which various
antiepileptics affect cognitive and behavioral aspects of
children with or without epilepsy. In contrast, somewhat
more information exists on the effects of beta blockers and
analgesics, and suggests that both of these medications

34
negatively affect verbal memory and learning (e.g., Kohler
and Fennell, 1992), at least in adults.
Some authors (e.g., Meador, Loring, Huh, Gallagher, and
King, 1990) contend that most of the more popular
antiepileptics have similar treatment efficacy, and
therefore differential cognitive effects should be given
appropriate consideration. Trimble and Cull (1988) reviewed
over a dozen studies on the effects of several
antiepileptics in children with varying types of epilepsy
and summarized their findings as follows: Phenobarbital
substantially impairs behavior, whereas valproate and
carbamazepine have little effect. Other medications have
far less data and await further research.
Adult Studies of Cognitive Effects of Valproate
In a longitudinal study of adults with a variety of
types of epilepsy, Dodrill and Wilensky (1992) followed 198
patients for five years that were on phenytoin monotherapy
or polytherapy. They concluded that there was no evidence
that long term administration of phenytoin is associated
with loss of cognitive abilities over time. Instead, they
infer that it is the effects of an epileptic condition that
cause cognitive decline, and because their subjects had
milder cases of epilepsy, no deterioration could be seen.
In order to lend support to their belief that it is the
epilepsy that causes the cognitive changes and not the
medication, drug trials on non-epileptic groups would be

35
beneficial. Because their study included adults only, they
admit that their results should not be applied to children
without further research on younger, pediatric populations.
Corbett, Trimble, and Nichol (1985) did show cognitive
deterioration in children on long-term antiepileptic
therapy, with those with higher phenytoin levels having
lower performance IQs. Verbal IQ was not affected.
Gallasi, Morreale, Lorusso, Procaccianti, Lugaresi, and
Baruzzi (1990) employed a withdrawal of medication design in
an adult epilepsy group of 20 patients who were seizure-free
for at least two years. They tested their subjects at four
points in time, ranging from baseline to 21 months. They
found significant differences between the epilepsy group and
controls on measures of reaction time and a global
performance measure that included all tests. This
difference was found at baseline and the second testing
(drug reduced to half). They compared the results to normal
controls who were only tested once, and asserted that the
gradual improvement they found was due to the gradual
removal of valproate. However, a significant practice
effect could account for this finding, since the controls
were not tested repeatedly. It is also noteworthy that
their findings, although statistically significant, were not
clinically significant, as none of the patients had noticed
any changes in the abilities measured. This finding is

36
consistent with the literature, which has shown only mild
differences, if any, as a result of valproate.
A study conducted by Sommerbeck, Theilgaard, Rasmussen,
et al. (1977) evaluated the psychotropic effects of
valproate in a heterogenous sample of epileptics. The
patients were given either valproate or placebo in
conjunction with other medications. This is a drawback for
this study that purported to find minor differences with
concurrent administration of valproate, because the impact
of the other medications cannot be assessed adequately.
Measures used included Digit Span, Paired-associate
learning, simple reaction time, Stroop's Color Naming test,
Hidden Patterns test, time estimation, a cancellation task,
a visual gestalt test, and motor tapping. The results
suggested that valproate caused declines in psychomotor
tempo and visuo-spatial analytic and synthetic functions.
However, these results are also suspect due to the small
sample size (20 patients) and the heterogenous nature of the
sample (e.g., the ages ranged from 13 to 63 years). Such
extraneous factors do not allow for strong conclusions.
Bittencourt, et al. (1992) also examined the three
medication groups (valproate, phenytoin, and carbamazepine)
in adults during drug administration. They found that the
epilepsy patients on phenytoin performed significantly worse
on the immediate recall for pictures than controls, those on
carbamazepine performed worse on the Stroop test than

37
controls, and those on valproate did not demonstrate any
appreciable difference from controls on these tests.
In addition to the research involving patients with
epilepsy, some researchers have attempted to assess the
effects of antiepileptics in normal controls. For example,
Boxer, Herzberg, and Scott (1976) found that a single dose
of valproate (400 mg) had hypnotic effects on medical
students used as controls. While this effect was greater
with the concurrent administration of phenobarbital, the
important finding was that valproate alone could produce
such effects. This study, however, was not without
methodological problems. The researchers only used eight
male subjects who were given only three psychological tests.
These tests consisted of a subjective report of sleepiness,
Digit Symbol, and a card sorting test (the authors did not
specify which). None of these measures showed any
differences. Their findings were based exclusively on EEG
record during a 30 minute period after only one dose of the
medication, one hour after administration. Perhaps the
biggest drawback to the study was their failure to measure
blood levels of the drugs used. Although the dosage was
equal for each subject (400 mg of valproate), there was no
apparent attempt to assess if the drug was in a therapeutic
range that would make the comparison more relevant to
clinical use.

38
In a better designed study, Thompson and Trimble (1981)
studied the effects of sodium valproate on cognitive
functioning in normal volunteers. Subjects were
administered 200 mg of sodium valproate or placebo for a
period of two weeks in a double-blind cross-over design. No
significant effects on memory, concentration, perceptual
speed, or motor speed were found. However, subjects did
require a significantly longer amount of time to answer
questions in a decision making task. Several reasons for
these results are possible. The dosage was less than that
used in the Boxer, Herzberg, and Scott (1976) study and may
therefore not create as strong an effect. The tests used by
Thompson and Trimble (1981) are not particularly demanding,
as memory was assessed through a simple recognition
paradigm, and other tasks were well within the range of
abilities for such a normal subject group (i.e., medical
students). Therefore, assessing the effects of valproate
would seem to necessitate using sensitive test measures to
reveal differences between control and experimental groups.
In order to investigate the effects of valproate on
sleep, reaction times, and visual evoked potential (VEP),
Harding, Alford, and Powell (1985) administered placebo,
low-dose, and high-dose conditions to 10 normal adult
volunteers. Withdrawal of medication effects were also
assessed. They found no significant treatment effect for
simple reaction time, nor did they find any differences in

39
either the latency or amplitude of the VEP. A decrease in
rapid eye movement and an increase in delta activity during
sleep was seen under the high-dose condition. Their lack of
findings could be a result of their small sample size,
particularly for the reaction time data, which was available
for only 6 of the 10 subjects due to technical difficulties.
The results from this study are consistent with those of
Thompson and Trimble (1981), however.
Child Studies
Duncan, Shorvon, and Trimble (1990) attempted to
examine the differences between several antiepileptic agents
(i.e., phenytoin, valproate, and carbamazepine) when they
were withdrawn from 58 children with partial and generalized
epilepsy. This method of assessing improvements following
the discontinuation of medication has the drawback of
assuming that these drugs have no residual, long term
effects. In fact, Duncan, Shorvon, and Trimble asserted
that their results supported the view that, since removal of
valproate resulted in the least improvement on
neuropsychological tests, it had the least negative impact
on the children who were taking it. This conclusion, while
it may have some validity, could be a misinterpretation of
an opposite effect. That is, if valproate has the more
detrimental, long lasting cognitive effects of the three
drugs, the results would have been the same. Regardless of
the final interpretation, Duncan, Shorvon, and Trimble found

40
that finger tapping was improved upon removal of all three
drugs, while letter cancellation, digit symbol substitution,
digit span, and serial subtraction, were not significantly
affected by the removal of valproate.
In a similar design, Blennow, Heijbel, Sandstedt, and
Tonnby (1990) reported tentative results in the midst of
their ongoing study. At the time they reported these
interim findings, 69 children with various types of epilepsy
had been studied, along with 69 matched controls (the
authors did not specify how control subjects were matched).
They described patterns such as faster reaction time at the
expense of accuracy for the valproate and carbamazepine
groups, slightly decreased motor fluency in the right hand
for the valproate and phenytoin groups (in contrast to
Duncan et al., 1990), and short-term memory decreases in all
groups treated for epilepsy. The last finding is difficult
to separate from the effects of long term epilepsy, however,
despite their use of a control group. The heterogenous
epilepsy group is also a common drawback in the study of
cognitive effects of antiepileptic medications, particularly
when the different types are not considered in analysis.
Vining, Mellits, Dorsen, et al. (1987) conducted a
double-blind counter balanced cross-over study of 21
children with epilepsy, comparing the cognitive impact of
phenobarbital and valproate. Patients were given a
neuropsychological battery three times: at baseline, after

41
six months on one medication, and after six months taking
the other medication. The battery consisted of tests
including intellectual assessment (Wechsler Intelligence
Scale for Children-Revised), measures of attention span and
sustained attention, motor tasks, achievement tests, mazes,
and the Bender-Gestalt, among others. While both
medications controlled seizures equally well, these authors
found that those patients on the phenobarbital performed
worse on certain subtests of the WISC-R (including verbal
and performance subtests), paired associate learning,
reaction time for errors on a continuous performance test,
and arithmetic achievement scores. Further, they found that
the patients on valproate earned more favorable scores on
parent questionnaires than those on phenobarbital. While
intriguing, these results must be considered tentative
because of the statistics used. With only 21 subjects,
these authors employed over 90 t-tests. Their findings may
be spurious rather than reflecting actual differences
between the side effects of the two drugs.
To assess the effects of dosage, fluctuations in
concentration, and diagnosis, Aman, Werry, Paxton, and
Turbott (1987) studied the effects of valproate in 46
children with epilepsy who received valproate monotherapy.
Three sets of tests were administered: measures of short¬
term memory, continuous performance task, mazes, pursuit
rotor task, and Matching Familiar Figures, with one week

42
intervals. The timing was altered to take advantage of
medication dosing (one test was administered pre-dose,
another post-dose), with the first test administered to
minimize subsequent learning effects. Subjects with lower
doses performed better on the psychomotor tasks than those
with higher doses. Timing of the dosing (pre- or post) did
not have an effect. Again, these authors over used the t-
test without considering their sample size. The age-range
of their patients was also rather broad (4.4 years to 15.4
years), making accurate interpretation of their data
difficult.
Forsythe, Butler, Berg, and McGuire (1991) utilized
more rigorous criteria for both subject population and test
measures. They targeted only new cases of epilepsy with no
neurological deficit, who had had either three tonic-clonic
seizures, three complex partial seizures, or three partial
seizures with secondary generalization. They employed an
appropriate experimental design, and monotherapy as opposed
to polytherapy. Michael Trimble served as consultant on
choosing appropriate test measures that would be most
sensitive, least affected by practice effects, high in
convenience, and would cause minimal fatigue and boredom.
Subjects were randomly assigned to one of three medications:
carbamazepine, phenytoin, and sodium valproate. After six
months of treatment, children on sodium valproate performed
significantly better on memory scores than children on

43
carbamazepine, and this difference was even greater after a
year. Speed of information processing was impaired in both
the carbamazepine and phenobarbital groups, this being
evident after only one month of treatment. The better
performance on memory scores with those on valproate
relative to those on carbamazepine may represent an actual
drug effect with the carbamazepine exerting a more negative
influence on memory. However, much of the research in this
area has employed tests that may not be as sensitive to
subtle, sub-clinical effects of memory and attention.
Future research should target these areas with measures less
susceptible to a ceiling effect or more likely to reflect
subtle differences.
In summary, several broad conclusions can be made about
the cognitive effects of antiepileptic medications.
Consistent with Vining's (1987) descriptions, these drugs
can be ranked by the degree to which they affect cognition.
Phenobarbital, which historically has the worst effects on
cognitive functioning, has its primary effect on short-term
memory, but also adversely affects long-term memory,
concentration, and symbol manipulation. Phenytoin
selectively impairs abilities related to problem solving and
visuomotor tasks, timed motor task, and attention.
Carbamazepine appears to have similar effects, although at
lower magnitudes. Finally, valproate appears to have
minimal effects, but may influence the most subtle aspects

44
of cognition. This makes sensitive neuropsychological tests
requisite in the assessment of differential effects.
Additionally, the research on the cognitive effects of
valproate is extremely mixed due to differences in
assessment tools, different populations, and varied
methodology (i.e., patients on polytherapy, blind versus
unblind, the use or lack of adequate controls). While some
research has been conducted on normal adult populations in
this area, comparable studies on children are lacking, in
part due to ethical considerations. Research on a non¬
epileptic pediatric group may provide the necessary data to
assess the effects of the medications in children.
Characteristics Specific to Valproate
Method of Action
The absolute method of action of valproate is
uncertain, although GABA has been the hypothesized
neurotransmitter involved. Typically given orally,
valproate is rapidly absorbed and reaches peak serum levels
approximately one to four hours after a single dose. The
serum half-life is typically 6 to 16 hours. Meals do affect
the rate of absorption, but only slightly.
While some support for GABA's involvement in valproate
exists, Johnston (1984) cites contradictory evidence. His
position on the GABA mechanism is that changes caused by
valproate cannot be attributed to an increase in the GABA
level, the potentiation of postsynaptic GABA responses, or

45
any direct membrane effect on neurons. Such an assertion
would appear to refute GABA's involvement. However, the
research on the mechanisms of valproate are far from
resolved, and the GABA hypotheses are not refuted as yet.
Animal models have shown that valproate can increase
GABA by inhibiting GABA transaminase. The significance of
this, however, is guestionable, because large
administrations of valproate (as much as 20 times a clinical
level) results in only modest and transient increases in
GABA levels (Emson, 1976). Valproate is, however,
considered to be a GABA agonist, which may affect migraine
via its influence on cerebral arteries and circadian rhythms
(Solomon, 1993). GABA dilates the cerebral arteries and may
help regulate hormone secretion from the anterior pituitary
gland.
It has also been purported that valproate has an effect
on serotonin metabolism, which would make intuitive sense
based on the potential role of serotonin in both migraine
and epilepsy (Van Woert and Hwang, 1978). In an animal
study of the effect of valproate on serotonin metabolism,
Hwang and Van Woert (1979) found that a single injection of
valproate (400 mg) decreased total serum tryptophan and
increased free serum tryptophan, brain tryptophan, and brain
5-hydroxyindoleacetic acid (5HIAA). However, they found no
effect on brain serotonin levels. They concluded that
valproate may act by displacing protein-bound serum

46
tryptophan which would result in an increase in brain
tryptophan, which would then be converted to serotonin.
In addition to proposing a mechanism for valproate and
serotonin (5-HT), Hwang and Van Woert also found differences
for various brain regions. For example, the largest effect
was a 46 percent increase in 5HIAA in the hippocampus.
Other areas showed increases as well, including the
hypothalamus, medulla, cortex, and striatum, although these
changes were not as large as that found in the hippocampus.
Despite the fact that these researchers did not report
differences in whole brain levels of 5-HT, there was a
significant increase found specifically in the striatum.
This level was elevated 113 percent over that of control
rats for this region. The overall elevated concentrations
of the various assays were attributed to increased 5-HT
synthesis. The authors suggested that the synthesis may
also be enhanced by 5-HT uptake blockade.
Using an animal model similar to that of Hwang and Van
Woert, MacMillan (1979) failed to support the hypothesis
that valproate acts to increase 5-HT synthesis. He argued
that the increase in 5HIAA was from decreased transport of
the metabolite out of the brain. An important difference
between his study and that by Hwang and Van Woert (1979) is
the lack of exploration into specific brain regions in the
MacMillan study. He acknowledged this as a potential
drawback, and it may hold the answer to the different

47
conclusions made from each study. Hwang and Van Woert
suggested that valproate may affect specific neuronal pools
(such as the striatum) that would obscure results from
studies that examined entire cortical levels of 5-HT, such
as in the MacMillan study.
Physiological Side Effects
As discussed above, valproate does not appear to have
as negative an effect on cognition as other antiepileptic
medications. However, similar to any drug, it does carry
certain risks to physiological functions. According to the
Physicians Desk Reference (PDR), valproate's most
significant physical side effect is hepatic failure.
Although not a common effect with valproate alone, signs of
sedation can be seen more commonly in conjunction with other
medications, particularly other anticonvulsants. Tremor is
a dose related side effect. More rarely, additional CNS
effects include ataxia, headache, nystagmus, diplopia, and
incoordination. It should be noted that none of these
symptoms are particularly common, and therefore do not pose
a significant threat to the child, although careful
monitoring is essential. Mattew and Ali (1991) noted that
some of the possible side effects may evidence themselves
frequently in certain subjects, such as hair loss (which
actually represents a speeding up of the normal process of
shedding of old hair), tremor, and weight gain.
Carnitine as a Supplement to Valproate Therapy

48
Research on the physiological effects of valproate have
revealed that children on such medication have significantly
lower plasma and erythrocyte free carnitine concentrations
than children on alternative antiepileptic medications
(Thom, Carter, Cole, and Stevenson, 1991). Carnitine is an
important nutrient found in the diet, plays an essential
role in the oxidation of fatty acids and in ketogenesis, and
some researchers have correlated a deficiency of this
nutrient with hepatotoxicity. Potentially toxic acyl
compounds may accumulate when the oxidation process of these
elements is impaired. Carnitine functions to regulate the
ratio of free coenzyme A (CoA) to acylcoenzyme A (acyl CoA)
in the mitochondrion (Coulter, 1991). The results from one
study indicated that free and total plasma concentrations of
carnitine decreased significantly after 15 days of valproate
administration in epileptic patients as compared to normal
controls (Riva, Albani, Gobbi, Santucci, and Baruzzi, 1993).
Murakami, Sugimoto, Nishida, Woo, Araki, and Kobayashi
(1992) showed in their research with rats that this change
in carnitine level resulting from valproate administration
could be altered to a more normal state with the concurrent
administration of carnitine. Giovannini, Agostoni, and
Salari (1991) argue that carnitine is an essential nutrient
for children, affecting multiple physiological functions
essential for development and growth. Therefore, it is

49
possible that carnitine may be supplemented for children who
are prescribed valproate to counteract such a deficiency.
Carnitine may not completely counteract the negative
effects of valproate, however. Siemes, Naue, Seidel, and
Gramm (1992) reported a case study of an infant who died
secondary to valproate complications despite the adjunctive
administration of carnitine. This finding was supported by
the research of Thurston and Hauhart (1992) who found that
carnitine administered to rats who had been given valproate
showed no effect on the reduction of free CoA and acetyl CoA
levels in the level. They found that this effect was only
achieved when carnitine was administered with pantothenic
acid. They asserted that their findings support the
hepatotoxic theory that valproate depletes CoA via
inhibition of B-oxidation and associated enzymic reactions.
Because CoA or acetyl CoA act as necessary substrates or
activators for approximately 100 synthetic and catabolic
enzyme reactions, the diverse effects of valproate can be
explained through this theory. The CoA levels are
diminished by the action of valproate, which may sequester
the substance into forms that are poorly metabolized. In
children with epilepsy, Melegh, Kerner, Acsadi, Lakatos, and
Sandor (1990) demonstrated that administration of carnitine
in conjunction with valproate over a period of 14 days did
not change the low plasma level of B-hydroxybutyrate. Total
carnitine levels were found to be lower in the children with

50
epilepsy compared to normal controls: however, this
difference was eliminated with the administration of
carnitine. Hypoketonemia was found to be carnitine
independent, though, which leaves the question of the
hepatotoxic role of valproate and the administration of
carnitine unanswered.
While research on the physiological impact of carnitine
deficiency is limited, cognitive or psychological effects of
such a deficiency in the face of valproate administration is
nonexistent. A need clearly exists for such research. One
potential reason for this lack of research is that there are
two forms of carnitine: L-carnitine and acetyl-L-carnitine.
The former is used in conjunction with valproate in some
cases to help prevent hepatotoxicity. Acetyl-L-carnitine, a
supposed cognitive enhancer, has been used in a few studies
of dementia and cognition, with its influence on the
facilitated production of acetylcholine, particularly in the
hypothalamus. Sinforiani, Iannuccelli, Mauri, Costa, Merlo,
and Bono (1990) examined the neuropsychological effects of
this form of carnitine supplement in a population of
demented patients. They found that, compared to
administration of piracetam, a neurotropic purported to
improve learning and memory, patients given acetyl-L-
carnitine showed significant improvements in attention,
comprehension ability, and specific behavioral aspects.
They also asserted that carnitine has been found to improve

51
memory impairment. Although the two forms of carnitine are
related (acetyl-CoA + carnitine acetylcarnitine + CoA) ,
they are typically used for different purposes, prohibiting
comparisons of their cognitive effects. However, Thom,
Carter, Cole, and Stevenson (1991) suggest that signs of
encephalopathy, in addition to confusion, may be a
neurologic symptom associated with severe L-carnitine
deficiency.
Studies of Valproate in the Treatment of Migraine
While valproate has not become a drug of choice for the
treatment of migraine, there is some support for its
efficacy. For example, a study by Hering and Kuritzky
(1992) to assess the efficacy of sodium valproate in the
prophylactic treatment of migraine supports the use of this
medication. They employed a double-blind randomized cross¬
over design with 29 adult patients. They were given either
400 mg. of valproate b.i.d. or placebo for eight weeks, then
crossed over to the other condition for another eight weeks.
Their results demonstrated that 86.2 percent of the patients
reported effective prevention of migraine or reduction of
frequency, severity, and duration of their migraines. The
drug was reportedly well tolerated (i.e., few adverse
effects). Interestingly, there was no correlation between
the effectiveness of the drug and blood levels. Also,
valproate only appeared to be effective in severe cases of
migraine. Another study (Mattew and Ali, 1991) also showed

52
a decrease in headache frequency in two-thirds of a group of
patients with intractable chronic daily headaches. They
did, however, report weight gain, tremor, hair loss, and
nausea. Neither study assessed the cognitive effects of
this treatment.
Summary
Based on the information provided in this literature
review, several conclusions become apparent. Migraine is a
phenomenon that is not uncommon in children and consequently
is receiving deserved attention from the field of medicine.
The neuropsychological and personality variables are less
well defined in this pediatric sample, allowing for further
research. Another point to be made about migraines is the
many links that have been drawn between migraine and
epilepsy. These include similarities on EEG, the presence
of aura, and familial components in some cases. An
additional intriguing similarity is the use of antiepileptic
drugs in both populations. While the use of these drugs in
the treatment of pediatric migraine has been challenged by
some, other research has shown them to be efficacious.
However, as has been shown in the epilepsy literature,
antiepileptic agents have potential drawbacks.
Phenobarbital, for example, has been shown to produce
sedative effects that may negatively impact attention and
concentration. Other drugs in this class, however, have
proved to be effective without such drastic side effects.

53
Valproate may have the least negative impact on
neuropsychological functioning, although the research on
this drug is severely lacking. One possible side effect of
valproate to be considered is that children to whom it has
been administered are at risk for carnitine deficiency and
subsequent hepatotoxicity. While the cognitive effects of
such a deficiency are not well described in children, at
least one study has shown that carnitine supplementation
improved cognitive functioning in a geriatric population.
Because most of the research in the area of cognitive
effects of antiepileptics in children has focused on
children with epilepsy, the confound arises that such a
population may have pre-existing differences in brain
functioning, and are therefore not an adequate population to
study in isolation. Migrainous children, then, are
potentially an excellent comparison group. Unfortunately,
the cognitive research on valproate and carnitine
supplementation in children is nonexistent, creating a need
for a well designed study with appropriate controls.
It would be necessary that such a study utilize
sensitive neuropsychological testing so as to describe even
the most subtle effects of both valproate and carnitine.
The questions to be answered include the following:
1. Are there any differences in personality or
neuropsychological functioning between migraineurs and
normal controls?
2. What are the cognitive effects of valproate?

54
3. What effect does carnitine supplementation have on
neuropsychological measures?

CHAPTER 2
METHODS
Subjects
Subjects were recruited from the pediatric clinic at
Shands Hospital as part of a drug study to examine the
treatment efficacy of valproate and carnitine in children
diagnosed with migraine. Accrual of subjects took place
over a 12 month period, beginning in January of 1993 and
ending in December of 1993. The mean age was 12.76 years
with a range of 9.17 to 15.83 years of age. The sample
consisted of 3 females and 11 males. An IQ screening
ensured that all subjects fell within a normal range of
intelligence (subjects with a mean scaled score below 8 or
any scaled score below 6 were excluded from the study). A
total of 14 subjects were recruited into the study and
administered baseline testing. Due to attrition, the sample
size decreased to 13 by the second testing, and to 6 by the
third testing. All subjects in the migraine group were
declared to be neurologically unimpaired by the pediatric
neurologist. EEG data for these subjects was read as
normal.
In addition to the migraine group, twenty control
subjects were recruited from area elementary and secondary
55

56
school, and a church youth group. Eighteen subjects
remained by the third testing. The age range for this group
was 7 years to 17, with a mean age of 12.08. The sample
consisted of 6 females, 14 males. There was no significant
difference in IQ between the control and migraine groups.
Materials and Apparatus
The following is a descriptive list of
neuropsychological tests used in this study:
Intellectual testing
Four subtests from the Wechsler Intelligence Scale for
Children-Revised (WISC-R) were used as an estimate of
intelligence. From the Verbal subtests, Comprehension and
Similarities both offer high split-half reliability (.77 and
.81, respectively) (Sattler, 1988). Similarities
correlates at .72 with Verbal IQ, while Comprehension
correlates .68. These particular subtests were chosen
because they offer high reliability across the age group
used in this study and are potentially less affected by
educational factors such as socioeconomic status and
educational level. Similarly, Block Design and Object
Assembly also offer good split-half reliability (.85 and
.70, respectively), and contribute information from the
Performance oriented side of the WISC-R. Block Design

57
correlates with Performance IQ .68, while Object Assembly
correlates at .60.
Together, these four subtests provided a good estimate
of IQ and served as a screening instrument, baseline, and
provided a description of the population during the initial
testing of all subjects. Because IQ was used to ensure a
normal range of intelligence for the subjects, these
subtests were administered only at baseline. The following
tests, however, were administered at each of the three
testing points.
Memory tasks
Verbal Memory
1. Buschke Selective Reminding Test (SRT): This test
of verbal memory is designed to measure verbal learning and
memory during a multiple-trial list-learning task. Each
subject was read a list of 12 words to remember, and then
was required to recall as many of the words as possible. On
subsequent trials, only words the subject failed to recall
on the previous trial were presented again. This format
offers the advantage of assessing which words are encoded
quickly (those that do not require additional prompting)
versus those that are difficult to encode. In addition, it
offers a measure of short term and long term memory, as well
as learning rate. According to Buschke and Fuld (1974),
this test maximized learning by directing the subject's
attention to those words not recalled on the previous trial.

58
Additionally, recall of an item without its presentation is
interpreted as evidence for encoding into long-term storage
(Levin, Benton, and Grossman, 1982), whereas short term
recall is reflected in items dependent on presentation.
The SRT has a number of different versions of the test,
thus making it ideal for repeat testing. Three versions
were used in this study. Clodfelter et al., (1987) state
that the different forms for children are roughly of
equivalent difficulty. Test-retest reliability is best for
the consistent retrieval aspect of the SRT at .92 (Masur et
al., 1989). Several dependent measures were obtained from
the SRT: immediate span, learning (total of items recalled
from trials 3 through 8), mean number of items recalled per
trial, and delayed recall.
2. Stories from the Wechsler Memory Scale: A modified
version of the Wechsler stories (Logical Memory - Form I and
Form II) (Wechsler, 1945) was used to assess immediate and
30-minute delayed memory. There are two stories of
approximately equal length from each alternate form of the
WMS. For purposes of this study, only one of the stories
was administered at any one testing time.
Each form of the WMS contains two different stories.
Both stories from Form I ("Anna Thompson" and "American
Liner") and the first story from Form II ("Dogs of War")
were used, in the order listed here. Although the two forms
of the WMS are not identical, the Logical Memory subtests

59
are considered to be sufficiently comparable (Spreen and
Strauss, 1991) and are of similar length. Because of
extensive research on reliability and validity as well as
detailed scoring and appropriate norms (Russell Revision),
these stories are a suitable choice for this study. Raw
scores were converted to z-scores by first doubling the raw
value (because norms are based on administration of two
stories), subtracting the normative mean for the subjects
age, and dividing by the standard deviation.
3. Digit Span: In Digit Span, the subject listened to
a series of orally presented digits and then repeated them
in the same order. This measure of short-term memory and
attention has good reliability (.78), but is not predictive
of general intelligence (Sattler, 1988). It is not
significantly affected by practice, and is therefore
appropriate for multiple testing. Normative z-scores were
obtained in the same manner as described above.
Nonverbal Memory
1. Corsi Cubes: Corsi Cubes, like digit span,
reguires the subject to repeat a seguence presented by the
examiner. However, instead of verbally presented digits,
the examiner taps cubes, that are one and a half inches in
dimensions, that are randomly ordered on a board. The
subject must then tap the blocks in the same order, or in
reverse order, depending on the examiner's instructions.
Because of the absence of verbal stimuli, it is considered

60
to be a test of nonverbal memory with spatial components.
It is no more susceptible to practice effects than digit
span, and is therefore appropriate for repeated assessment.
Z-scores were obtained for forward and backward span,
providing two dependent measures.
2. Visual Learning from the Wide Range Assessment of
Memory and Learning (WRAML): The Visual Learning subtest
from the WRAML has a median reliability coefficient of .88,
while test-retest reliability is .81 (Sheslow and Adams,
1990). On this test, the child was presented with visual
designs which are arranged in particular positions on a
board. The child had to remember the spatial location of
the design, while the design is covered by sponge shields,
over a period of four trials. The color and aesthetic
qualities of this task make it ideal for children. Based on
its reliability and nonmeaningful stimuli, repeated testing
should not produce significant practice effects. A scaled
score based on the total number of correct responses was
obtained using the age-appropriate norms provided by the
WRAML manual.
Motor Tasks
1. Finger tapping: This task required subjects to
place their hand on a board with their index finger
positioned over a metal key. When depressed, this key
advances the numbers on a counter so that a tapping rate per
ten second interval may be obtained. Each hand was tested

61
on four trials each, and the rate was averaged across trials
to yield a number for each hand, which was then translated
to z-scores. Brown, Rourke, and Cicchetti (1989) conducted
research on the reliability of different neuropsychological
tests for children. Although they claimed to have found the
reliability for finger tapping to be excellent (.60) for the
dominant hand, and good (.58) for the nondominant hand,
these numbers are modestly reliable. The use of a control
group was intended to control for extraneous factors.
2. Beery Test of Visual Motor Integration (VMI); The
VMI is designed to measure perceptual-motor abilities by
requiring the subject to copy up to 24 geometric forms.
Reliabilities for the VMI range from .81 for test-retest, to
.93 for interrater reliability. Sattler (1988) comments
that the validity is satisfactory, and though the
standardization sample included 3,090 children, it is not
well defined. This test is not likely to be significantly
affected by environmental factors such as medication, and
was chosen to offer a useful comparison to other, more state
oriented measures. It was administered to subjects only at
the first and last testing. An age-based standard score was
obtained.
Attentional Tasks
1. Computerized Continuous Performance Task (CPT):
The CPT can be of two types: vigilance or reaction time.
One common reaction time format is the single-choice

62
reaction time (RT), which requires the subject to press one
of two keys immediately after cue presentation. For
example, if the letter X appears on the screen, the subject
presses a key with their left hand (such as the letter Q on
a standard key board). If the letter Y appears, they must
press a key with their right hand (such as the letter P).
The stimuli are presented at random points on the screen.
This format was used in this study to assess reaction time
changes with the administration of valproate.
The value of such a task is that some degree of speeded
decision making must take place in the context of sustained
attention in order to perform correctly. The added element
of having to choose between two responses modestly increases
the level of difficulty, therefore creating a more sensitive
test measure. In a study by Fennell, Fennell, Carter, Mings,
Klausner, and Hurst (1990), this type of task was used
effectively to show differences between a renal pediatric
population and controls. Because it is computer
administered, repeated presentations can be identical or
varied slightly (such as changing the stimulus letters) to
control for learning effects. The motor output is minimal,
leaving the effects of speeded decision making and attention
clearer.
The CPT is programmed on an IBM computer (Fennell, et
al., 1990). For purposes of this study, the program was run
on either a Leading Edge portable computer to accommodate

63
change in testing site, or a standard IBM computer. The
task was a simple-choice reaction time in which the subject
had to respond to the letter X by pressing the Q key on a
keyboard, and to the letter Y by pressing the P key on the
keyboard. The letters were presented singly (i.e., one X or
one Y) at random spatial locations on the screen, at random
intervals. The intertrial intervals alternated between 2,
5, and 8 seconds. Exposure time alternated between .3, .6,
and .9 seconds. Each of the 108 trials was repeated twice
for a total of 216 presentations. Correct responses were
those where both of each repeated trials were responded to
correctly. Mean reaction time across all trial pairs and
conditions served as the primary dependent measure for this
task. No normative data is available for this task,
necessitating the use of covariate statistics in analysis.
2. Paced Auditory Serial Addition Test (PASAT): The
PASAT is a serial addition task typically presented via
audio tape. This method of administration controls for rate
of presentation and difficulty level, which can be 2.4, 2.0,
1.6, or 1.2 seconds per digit, with a total of 61 digits per
trial. The subject is required to listen to a series of
digits and, upon hearing the second, add it to the first,
then adding the second to the third number, and so forth.
For example, upon hearing "3, 7", the subject should answer
"10". If the next digit is "5", the subject should arrive
at "12", by adding 7 and 5.

64
This test reportedly is a sensitive measure of
information processing and sustained attention (Gronwall and
Wrightson, 1981). Gronwall and Sampson (1974) describe the
PASAT as a test that assesses some central information
processing capacity analogous to that seen on reaction time
and divided attention tasks. Because of its difficulty and
attentional demands, it is an ideal test to measure subtle
changes in the ability to process information at a given
rate.
One drawback to the PASAT is the evidence of
significant practice effects (Gronwall, 1977). However,
after the second presentation, these practice effects are
not a factor as performance does not continue to improve at
such a rate. For the second presentation, though, a control
group is requisite to compare practice effects and tease out
their impact versus the impact of medication. Spreen and
Strauss (1991) report excellent split-half reliability (.96)
for this measure.
Subjects were administered the 2.4 and 2.0 second
interval trials. A total of 49 correct responses for each
of the two conditions was possible. Normative data allowed
for z-score transformation.
Parent Report
Child Behavior Checklist ÍCBCL): A commonly used
parent report child assessment tool is the Child Behavior
Checklist (Achenbach & Edelbrock, 1986). The CBCL can be

65
self-administered to the child's parent or guardian. The
CBCL provides separate norms for 3 age groups: 4 to 5, 6 to
11, and 12 to 16 by sex. There are subscales within each
age group, as well as the two broad-band factors of
Internalizing and Externalizing. Children who rate as
externalizers may be seen as more overactive and as
possessing more conduct problems than those who rate as
internalizers. Factor loadings from the narrow-band scales
justified the labels "Interalizing" and "Externalizing.”
The CBCL is very well standardized and has adequate
reliability and validity. It is reported by DuPaul et al.
(1991) to be the best standardized rating scale in use.
Due to the number of variables and relatively small
sample size, the data from the CBCL was summarized into an
Internalizing score and an Externalizing score (both scaled
as t-scores). A third variable was a simple bipolar
assignment which was made for each subject according to
whether they did or did not have any scale scores that were
in a clinically significant range (i.e., > 70).
Procedures
A screening battery was administered to all subjects
prior to their introduction to medication. This battery
included all test instruments listed above, including the IQ
screen and parent report measures. In the second and third
testings, however, IQ was omitted, and the CBCL and VMI were
omitted from the second testing. Following baseline

66
testing, all migraine subjects were then given valproate for
the period of four weeks, after which they were retested to
assess any changes in neuropsychological functioning as a
result of the valproate. Valproate dosage was established
according to weight of the subject, and was titrated
according to blood levels (goal therapeutic range was 50 to
100 ml). Following the second assessment, subjects were
randomly assigned to one of three groups: 1) Group 1
continued on valproate and also receive carnitine; 2) Group
2 continued on valproate and received a carnitine placebo;
and 3) Group 3 received placebos for both valproate and
carnitine, and was therefore drug free. Subjects remained
in their respective groups for a period of 8 weeks, after
which they were tested for a third and final time (see
Figure 1).
Test order was constant across testings. For the
initial testing, the IQ screening will be administered,
followed by a 10 minute break. During this break, the
subtests were scored to determine if the subject met the
minimum criterion for admission to the study. This break
also served to minimize any fatigue effects of the IQ screen
before the actual test battery was administered. The
remaining tests were given in the following order: WMS
story (immediate), CPT, PASAT, WMS story (delay), Finger
Tapping, SRT learning trials, Visual Learning (WRAML), Digit
Span, Corsi Cubes, SRT delay, Visual Learning delay, and VMI

67
(the VMI only on first and third testings). The CBCL was
completed concurrently during the first and third testings.
During the initial four week period when all subjects
were taking valproate, only the subjects were blind.
However, when the subjects were randomized into one of three
groups, both subjects and experimenters were blind to
condition.
Hypotheses
(1) There will be no significant differences on
neuropsychological tests between the migraine children and
the control group at baseline.
(2) Parent report (CBCL) will reveal subtle
differences on scales such as somatic complaints and
anxiety. This difference is not likely to be significant
given the effect and sample size.
(3) Following one month of valproate therapy, the
experimental group will perform worse than the nonmigraine
control group on neuropsychological tests that are most
sensitive. Attention oriented tasks (CPT reaction time and
the PASAT) and memory (verbal and nonverbal) tasks will be
the most likely to reveal differences between the groups.
(4) After dividing the experimental group into three
subgroups, the group who is receiving carnitine supplement
will perform better on sensitive neuropsychological tests
than those who are not receiving the supplement, although
this difference may not be statistically significant.

68
However, there will be a significant difference in
performance such that the third group (those on valproate
placebo and carnitine placebo) will show significantly
better performance than the other two groups. This implies
that valproate will have the most negative impact on
cognitive functioning. Finally, none of the experimental
groups will perform better than the nonmigraine control
group.
(5) After receiving treatment for their migraines,
there will be a decrease in parent report of behavioral
problems, such as anxiety or somatic complaints.

69
TABLE 2-1
SUBJECT CHARACTERISTICS
MIGRAINEURS
CONTROLS
Mean Age
12.8 (2.2)
12.1 (3.
Age Range
9-15.8
7-17
Female/Male Ratio
IQ subtest means
3/11
6/14
Similarities
11.4 (2.2)
12.3 (3.
Comprehension
10.2 (2.2)
13.1 (2.
Block Design
9.2 (2.6)
11.1 (2.
Object Assembly
10.4 (4.0)
11.5 (3.
Number of Subjects
at baseline
14
20
NOTE: Standard deviations are provided in parentheses.

CHAPTER 3
RESULTS
There was no significant overall group effect for IQ.
All subjects were considered to be within a normal range of
intelligence.
Descriptive statistics were conducted for both groups
at baseline. Table 3-1 provides the means and standard
deviations for both groups separately and as a whole for all
variables used at baseline. Table 3-2 provides the same
statistics for scores at the second testing.
The first hypothesis for this study was that children
with migraine would not differ from the control group at
baseline measurement. To assess the validity of this
hypothesis, a multivariate analysis of variance (MANOVA) was
conducted on the domain scores for each subject at baseline
to determine if there was any significant difference between
migraineurs in an unmedicated condition and controls.
Specifically, items related to verbal memory constituted one
domain and was analyzed together, as were nonverbal memory
items. Domains analyzed were as follows: Verbal Memory
(Logical Memory and the Buschke SRT), Nonverbal Memory
(Visual Learning from the WRAML), Memory Span (Digit Span
and Corsi Blocks), Attention (PASAT and the CPT reaction
70

71
time), Visual-Motor (VMI), and Behavior (CBCL). By grouping
the variables into MANOVAs as described, the number of
statistical analyses was reduced in an attempt to control
for a Type I error. For the Attention domain, a MANCOVA
(multivariate analysis of covariance) with age as the
covariate was reguired because of a lack of normative data
for the CPT. The study by Fennell, et al. (1990)
demonstrated that there were age effects for reaction time,
such that reaction time decreased as age increased. The use
of a MANCOVA was intended to take this age effect into
account for these analyses.
At initial testing, no significant differences were
seen between the migraine and control groups on any of the
neuropsychological tests. A t-test to assess any
differences on the VMI approached significance (p = .052),
with the migraineurs reflecting a lower mean score for the
VMI than the control group.
The second hypothesis was that the parents of
migrainous children would endorse more problem behaviors,
particularly those considered to be a reflection of somatic
complaints, than parents of the control children. Scores
from the CBCL were summarized into t-scores for
externalizing and internalizing factors. The mean

72
internalizing score for the migraine group was 61.85, and
the mean for the externalizing score was 55.08. Because too
few parents returned the CBCL for the control group, the
migraine group scores were compared to the published
normative data using a Welch's T-test. For the normative
data, mean scores are 50 with a standard deviation of 10.
Using this method, a significant difference resulted for the
internalizing factor (p < .05) but not for the externalizing
factor. The mean number of clinically elevated scales for
the migraine group at baseline testing was 2, with a range
of 0 to 9. The most commonly elevated scale was Somatic
Complaints.
The third hypothesis tested was that subjects taking
valproate after one month would perform significantly worse
on measures of memory and attention than the non-medicated
control group. A repeated measures MANOVA was conducted for
each domain for the first and second testings to assess the
effect of introducing valproate to the migraine group.
Results from this set of analyses resulted in no significant
group effect for any of the neuropsychological domains
measured. The repeated measures MANOVA for Span was the
only domain analysis that approached significance (F = 2.46,
p = .069).
After examining the blood levels of valproate for the
migraine group, it was apparent that many of the subjects
were not in a therapeutic range (i.e., 50 or higher).

73
Therefore, another set of repeated measures MANOVAs was
performed with different groupings. Because there were no
significant differences observed at baseline between the
migraineurs and controls, those migraineurs who were not
considered to have a therapeutic blood level of valproate
were re-assigned as controls for this analysis. Therefore,
the groupings resulted in those migraineurs with a
therapeutic blood level of valproate versus all other
subjects. The results from this analysis yielded a
significant group by time interaction on only the Attention
domain (F = 5.06, p = .036). This was actually a repeated
measures MANCOVA, with age as the covariate due to a lack of
age norms for the CPT reaction time data. The results
indicate that group membership and time of testing (i.e.,
after one month of valproate therapy) were important
variables on the Attention domain.
Difference scores were obtained between the variables
on testing one and two, and a correlation analysis was
conducted on these difference scores and the blood levels
obtained at the second testing. This analysis therefore
includes only migraineurs. Although none of the
correlations obtained were statistically significant,
several did approach significance. Both the fast and slow
trials of the PASAT were close to significance (p = .083 and
p = .058, respectively), but in opposite directions. The
fast trial of the PASAT revealed a positive correlation

74
while the slow trial revealed a negative correlation. The
immediate recall of Logical Memory also neared significance
(p = .064, positive correlation), as did Visual Learning
from the WRAML (p = .062, negative correlation). These may
have reached significance with a larger sample (total sample
size for these correlational analyses ranged from 11 to 13).
The fourth hypothesis involved data from the third
testing, after migraine subjects were randomly assigned to
one of three groups (valproate plus carnitine, valproate
plus placebo, and placebo plus placebo). The results from
the third testing were unable to undergo statistical
analysis because of a high attrition rate resulting in an
extremely small sample with group sizes of one to three
subjects. Correlations between blood level and the third
testing did not result in any significant relationships,
perhaps due to the even smaller sample size.
The fourth hypothesis also predicted that carnitine
would improve cognitive functioning in those subjects
receiving valproate, but this difference would not be
statistically significant. This could not be analyzed due
to the severe attrition. Additionally, there was no
eguivalent check for compliance as there was for the
valproate as measured by blood level. Therefore, even those
subjects assigned to take carnitine were not clearly under
the influence of the supplement.

75
The fifth hypothesis was that migraineurs would show
improvement by the third testing with the administration of
valproate on parent report of problem behaviors. The CBCL
data was analyzed for the seven subjects remaining at the
third testing. Neither the internalizing or externalizing
scores differed significantly from the normative data.
Although this is consistent with the hypothesis, the
internalizing score remained higher than the externalizing
score (64.29 compared to 59.14), indicating that problems
behaviors in this domain were still perceived by parents to
be more problematic than the externalizing behaviors.
Failure to reach significance is probably due to sample
size, given that the means are slightly higher than at
baseline. The increase in means from baseline to third
testing is likely a result of differential attrition, but
this was also not significant. Also, not all subjects were
in a therapeutic range of valproate because of group
membership and due to compliance issues.
Post-hoc Analyses
A significant practice or test order effect (F = 7.85,
p = .01) was observed for all subjects for the Visual
Learning test that comprised the Nonverbal memory domain, as
well as Logical Memory (p = .000).
A Chi-Square was performed to determine if group
membership among the migraineurs (i.e., placebo versus drug
conditions) predicted attrition. From the valproate plus

76
carnitine group, 75 percent dropped out, while 57 percent
attritted from the valproate plus placebo group, and 25
percent attritted from the placebo plus placebo group.
Although these numbers appear to be significant, Chi-Square
analysis did not support this (p = .35). This lack of
statistical finding may also be due to a relatively small
sample size.
A test of binomial proportion was conducted on two
groups (the two groups administered valproate were collapsed
into one group and compared to the placebo plus placebo
group). The corresponding rates of attrition for the groups
were 70 percent for the valproate group, and 25 percent for
the placebo group. This approached significance (p = .062).
To determine if adolescents were more likely to be
noncompliant than children, the migraineurs were divided
into two groups: those 13 and older, and those 12 and
younger. A t-test based on these two groups and comparing
the mean blood levels after one month of valproate therapy
resulted in a significant finding (p = .002), such that
adolescents had a lower mean blood level. Among the seven
adolescents in this analysis, five had blood levels that
were not in a therapeutic range (i.e., less than 50). All
of the children (ages 12 or younger) had blood levels over
50.
Finally, to determine if compliance was related to
socioeconomic status, the subjects were divided into those

77
that were labelled medically needy and receiving aid from
Children's Medical Services, and those who had private
insurance coverage. This did not result in a significant
difference in blood level between the two groups.

78
Table 3-1
Means and Standard Deviations for Migraine and Control Group
at Baseline
All Migraineurs Controls
(The following group means are based on scaled scores)
Visual
Learning
10.2
(2.66)
9.5
(2.20)
10.7
(2.90)
(The following
group
means
are based on z-scores)
Logical Memory
(immediate)
Logical Memory
.84
(1.66)
.74
(1.98)
.93
(1.35)
(delay)
.92
(1.51)
1.10
(1.79)
.75
(1.21)
Digits Forward
-.69
( -61)
-.94
( -39)
-.50
( -68)
Digits Backward -.67
( -53)
-.60
( -42)
-.72
( -61)
Corsi Forward
-.54
( -54)
-.74
( -57)
-.38
( -54)
Corsi Backward
.37
( -62)
.48
( -66)
.30
( -60)
PASAT Slow
-.82
(1.26)
-1.27
(1.43)
-.43
( -98)
PASAT Fast
-.77
( -97)
-1.10
( -98)
-.49
( -89)
Motor Tapping
-.32
(1.02)
-.26
(1.24)
-.36
( -87)
CPT Reaction
Time
40.19
(9.20)
41.64
(10.0)
39.2
(8.81)
VMI Standard
Score
99.10
(9.52)
94.38
(6.80)
102.0
(10.0)
CBCL Intern.
T-score
61.85
(9.95)*
CBCL Extern.
T-score
55.08
(11.8)*
* The migraine group was compared to the published normative
data for these measures. Therefore, no means are listed for
the control group.

79
Table 3-2
Means and Standard Deviations for Migraine and Control Group
at Second Testing
All Migraineurs Controls
(The following
group
means
are based
on scaled scores)
Visual
Learning
11.55
(3.25)
10.92
(3.45)
11.95
(3.14)
(The following
group
means
are based
on z-scores)
Logical Memory
(immediate)
-.63
(1.40)
-.83
(1.72)
-.50
(1.17)
Logical Memory
(delay)
-.58
(1.39)
-.81
(1.74)
-.41
(1.13)
Digits Forward
-.60
( .65)
-.97
( -38)
-.37
( -68)
Digits Backward -.38
( -72)
-.32
( -93)
-.42
( -56)
Corsi Forward
-.21
( .65)
-.40
( -58)
-.08
( -68)
Corsi Backward
.49
( -68)
.40
( .47)
.55
( -79)
PASAT Slow
-1.24
(1.25)
-1.83
(1.26)
-.82
(1.09)
PASAT Fast
-1.04
( -96)
-1.46
( -81)
-.74
( -97)
Motor Tapping
. 32
(1.16)
. 12
(1.03)
.43
(1.23)
CPT Reaction
Time
47.94
(14.9)
50.44
(21.5)
47.0
(12.7)
(The following
scores
were
obtained
from the third
testing)
VMI Standard
Score
106.2
(10.7)
102.20
(13.8)
107.4
(9.77)
CBCL Intern.
T-score
64.29
(12.5)*
CBCL Extern.
T-score
59.14
(14.24)*
* The migraine group was compared to the published normative
data for these measures. Therefore, no means are listed for
the control group.

CHAPTER 4
DISCUSSION
The literature is represented by heterogeneous results in
the studies of both migraine and valproate. The underlying
mechanisms of both continue to be disputed. In addition to
the discrepant findings on the neuropsychological effects of
migraine in adults, the introduction of childhood and
adolescent migraine further clouds the picture. Several
authors have claimed to have found neuropsychological
differences between adult migraineurs and controls (e.g.,
Kohler & Fennell, 1992; Crisp, Levett, Davies, & Rose, 1989;
and Hooker & Raskin, 1986), while others assert that no
differences exist (e.g., Leijdekkers, et al., 1990; Burker,
Hannay, & Halsey, 1989). Their discrepant findings may be the
result of a number of different factors, including
inappropriate statistics conducted on relatively small sample
sizes, leading to spurious results. Other factors may include
the use of cognitive tests that paint the neuropsychological
picture in broad strokes rather than using more sensitive
measures that target subtle cognitive changes. Additionally,
the ages of the subjects and migraine history may play a key
role in the findings. Regardless of the adult studies on
migraine and cognitive functioning, there remains to be
80

81
addressed the question of cognitive differences in children or
adolescents with migraine. They may comprise a different
subset of migraineurs due to the necessarily different history
of the migraine process.
The debate over the neuropsychological impact of
antiepileptic medications has also yet to be resolved. Older,
supposedly more detrimental medications such as phenobarbital
have been examined in several studies and their cognitive
impact has been described. However, the effects of valproate
remains controversial regarding whether patients receiving the
medication suffer a compromise in certain aspects of
neuropsychological functioning. One problem in assessing this
medication is the population used to test its effects.
Historically, adults or children with epilepsy have been a
favored sample on which to demonstrate the effects of
valproate, among other similar medications. The results have
been mixed with this method (e.g., Aman, Werry, Paxton, &
Turbott, 1987; Bittencourt, Mader, Bigarella, & Doro, 1992;
Blennow, Heijbel, Sandstedt, & Tonnby, 1990) and the methods
employed have included both the administration of valproate in
polytherapy, and the withdrawal of medication in presumably
stable epilepsy patients. The drawbacks to this population
are obvious: epilepsy patients may have poorer
neuropsychological performance due to the epilepsy rather than
to the medication. It is unethical to place a patient with
epilepsy in a placebo control group, therefore making the

82
distinction between the epilepsy and drug effect uncertain.
Withdrawal studies also due not control longer lasting effects
of medications well, although blood levels may control for
some of this effect.
Additional studies of the effects of valproate have
included normal adult volunteers to assess the effects of the
medication (e.g., Harding, Alford, & Powell, 1985; Thompson &
Trimble, 1981). This method is also not without its
drawbacks, however. Most studies of this type only administer
the medication for short periods of time, often without a
blood level check to ensure therapeutic levels. The few
studies of this type are also plagued with methodological
problems such as poor assessment of neuropsychological
abilities and inappropriate statistical procedures. Although
this method may prove beneficial under the appropriate
conditions, to date these results have not yielded
substantial, useful information. Additionally, it is a method
that would preclude the use of normal children in most cases,
therefore omitting important data regarding this potentially
different group.
Several studies have documented the efficacy of valproate
as a prophylactic medication for migraine (e.g., Sorensen,
1988; Hering & Kuritzky, 1992). This provides another
population useful for studying the cognitive effects of the
medication, particularly in children. Although some studies
have determined that migrainous individuals may have some

83
different neuropsychological deficits, this has yet to be
demonstrated in children. If in fact, migrainous children are
not significantly different on cognitive measures that other
children without medical compromise, then they would provide
an excellent opportunity to assess more pure effects of
valproate.
Interpretation of Findings
Several important findings result from the current study.
First, no significant differences were found on baseline
testing measures between the migraine group and the control
group. This study is one of the first to examine the
potential for neuropsychological differences in an adolescent
migraine group. Results suggest that there are no
neuropsychological differences between children and
adolescents with migraine and a similar group of controls.
One exception to this is the difference between groups on the
VMI (p = .052). Although this finding suggests differences in
visual motor integration, this finding was not apparent at the
third testing, perhaps due to the decreased sample size.
Overall, the finding of no difference at baseline (unmedicated
state) is in contrast to a few of the adult studies that have
found differences on cognitive measures. One potential reason
for this is differences in methodology and statistical
procedures. Another interpretation, however, is that a
fundamental difference exists between adults and children with
migraine. Some have suggested that migraine, like epilepsy,

84
compromises the brain through repeated vascular attacks
(Farkas, Kohlheb, Benninger, & Matthis, 1992; Levitón,
Malvea, & Graham, 1974; Eviatar, 1981) that may have long¬
term, permanent effects. Therefore, patients with a longer
history of migraine would be more likely to exhibit cognitive
impairments. Children and adolescents with migraine, however,
may not have the extended history of migraine necessary to
demonstrate such impairments. Additionally, the fact that
children are less likely to be diagnosed with classic migraine
than adults may also play a role in the cognitive differences
between these populations.
Despite a lack of differences found on neuropsychological
measures, migraineurs did demonstrate higher internalizing
problem scores on the CBCL than is expected from the general
population. Externalizing behaviors were not reported as
being significantly different. These results are not
surprising given the frequency of scale elevations for Somatic
Complaints, which contains report of headache. However,
several subjects had more than one scale elevation, which may
reflect personality differences in adolescents with migraine
versus their headache-free peers. This is consistent with the
research on adult migraine (e.g., Leijdekkers, et al., 1990;
Burker, Hannay, & Halsey, 1989) that has supported differences
in personality even without evidence of neuropsychological
differences. Research examining personality characteristics
of adolescent migraineurs (e.g., Andrasik, et al.,
1988;

85
Cooper, et al., 1987) has found higher reports of depression
(which is considered to be an internalizing behavior on the
CBCL), among other behaviors, and supports the findings from
this study.
Analyses conducted on the first and second testings
indicated that valproate has little effect on most
neuropsychological domains with the exception of attention.
This finding was only borne out when the subjects were re¬
grouped according to therapeutic blood level, which lends
further support to the finding that migraine group membership
alone does not reveal differences. It may be that the
measures of attention used in this study are more sensitive to
subtle alterations in functioning caused by valproate than the
other measures. Attention itself may be more sensitive to
external factors than memory, although greater degrees of
impairment in attention are likely to have a negative effect
on memory. The findings by Hwang and Van Woert (1979) that
valproate has a greater effect on striatal and hippocampal
areas of the brain supports the differences found in attention
in this study because of striatal connections with frontal
lobe structures, but does not explain the apparent lack of
results regarding memory. Again, varying degrees of test
sensitivity may be the cause.
Unfortunately, the original design intended could not be
analyzed due to the degree of attrition. The third testing
was originally intended to measure the effects of valproate

86
with placebo controls in a double-blind manner, as well as the
concurrent administration of carnitine. With only three
subjects remaining that were taking the carnitine supplement,
statistical analysis was impossible. Additionally, these
subjects demonstrated a level of noncompliance with the
valproate that could be measured with blood levels, but this
method was not possible with carnitine. Therefore, of the
three subjects assigned to carnitine, all or none of them
could have actually been taking the supplement. Analysis,
even qualitative, would be rendered meaningless. Although not
significant, a greater number of subjects in the valproate
plus carnitine group dropped from the study, with the
valproate plus placebo group comprising the next largest group
of drop-outs, followed by the placebo plus placebo group. The
negative side effects of the medication may have been the
cause of this differential attrition, as well as the aversive
taste of the carnitine (one subject confided that he was not
taking the carnitine for this reason).
Adolescent Noncompliance
Because compliance was such a significant factor in this
study, this topic deserves further discussion. The literature
on compliance in adolescents and children has increased
significantly over the past two decades. In an extensive
review of the compliance literature, Dunbar-Jacob, Dunning,
and Dwyer (1993) noted that 91 studies were conducted in this
area between 1970 to 1989, with research ranging from simple

87
assessment of compliance to intervention or treatment designed
to increase compliance. However, of the 91 studies conducted
during this time span, none included specific assessment of
the compliance of migrainous adolescents. Also, a search for
research employing such a population between 1989 and 1993 was
unsuccessful. Despite the lack of research on a migrainous
population, the results of numerous other studies on
compliance in adolescents are helpful in attempting to
understand better the underlying causes of the low compliance
in this study.
The literature on childhood compliance in general reveals
dramatically poor adherence to medication regimens, even with
potentially life-threatening illnesses such as cancer. This
low level of compliance has been shown to be worse for
adolescents compared to younger children (e.g., Tebbi, 1993;
Johnson, 1993). In a study specifically designed to assess
the level of compliance in adolescent patients with acute
lymphoblastic leukemia or Hodgkin disease, 52 percent of the
patients were noncompliant with their prednisone therapy,
while nonadherence was demonstrated in 48 percent of those
prescribed penicillin for post-splenectomy prophylaxis. These
findings are not unusual, which is demonstrated by the
findings of Ettenger et al. (1991). They found a medication
noncompliance rate of 50 percent in 70 pediatric renal
transplant patients. The rate was slightly higher for

88
adolescents (64 percent). Unfortunately, the result of this
noncompliance was a 13 percent loss of transplant graft.
Given that the literature has supported the belief that
adolescents generally demonstrate poor compliance with medical
regimens, the focus then should be on what factors contribute
to poor compliance and how compliance might be improved among
this group. Brooks-Gunn (1993) detailed several
biopsychosocial risk factors influencing adolescent health
behavior. One of these factors is the cultural context in
which the adolescent is embedded. Different cultural views on
medical adherence and the locus of responsibility (i.e., who
is responsible for the administration of medications) can
impact the level of compliance achieved in a given population.
In addition to cultural factors, individual factors also play
a significant role. These include biological (e.g., hormonal
changes and levels of depression), emotional, and social-
cognitive (e.g., perceived costs and benefits, risks, and
future consequences) factors. These issues are particularly
relevant in the adolescent population who are often seen as
being naive to consequences of risky behavior. Environmental
factors may also play a role in compliance, particularly via
the influence from peers and parents. As children enter
adolescence, conformity becomes increasingly important.
Perceived differences between the patient and peers based on
medication usage and side-effects may contribute to
noncompliance. An important variable is the parental

89
influence, which may become less as the adolescent becomes
increasingly independent. In fact, it has been stated that
parents themselves become less compliant with medical regimens
as their children enter adolescence (S. B. Johnson, personal
communication). A final environmental factor is that of the
physician/patient communication. The patient may feel that
they are being compliant, but due to poor communication, they
may actually have gaps in their knowledge about the medication
or treatment plan that leads to inadvertent noncompliance
(Johnson, 1993). This is most likely to be problematic for
younger children, but can also be seen in adolescents.
In a study of the psychosocial determinants of compliance
in adolescents with iron deficiency, Cromer, Steinberg,
Thornton, and Shannon (1989) reported a 67 percent compliance
rate. Factors they found to be statistically significant
predictors of compliance included side effects of the
medication and freguency of family reminders to take the
medication. This suggests that, even with adolescents,
instruction to the parents to become more involved in their
children's medical adherence may be beneficial. Also, the
report that negative side-effects tended to decrease
compliance is consistent with the descriptive results from
this study, in which several patients complained of negative
side-effects.
The concordance of parent and adolescent views on
medication has been explored in at least two studies. Tebbi,

90
Zevon, Richards, and Cummings (1989) measured cancer patients
and their parents on attributions related to their degree of
perceived responsibility. These authors failed to demonstrate
a relationship between parent-child concordant attributions
and medical compliance. However, in an earlier study, Tebbi
et al. (1988) did find that compliance was greater when
parents and patients agreed on who was responsible for
administration of the medication and their understanding of
instructions and effectiveness of the medication. This would
theoretically alter the diffusion of responsibility (which
would likely reduce adherence) by placing the responsibility
on one individual. However, even in such a model, parental
support would likely benefit the adolescent.
Noncompliance has also been associated with a restriction
of the adolescent's independence, low self-esteem, and poor
family relations (Friedman, 1986). One method of increasing
compliance, therefore, would appear to be increasing self¬
esteem and perceived independence, as well as clarifying to
both the parent and adolescent who is primarily responsible
for the administration of the medication. This is consistent
with the research of Tebbi et al. (1988). Weinberger (1987)
noted that compliance can also be enhanced by including the
patient in decision making in order to foster an internal
locus of control. These suggestions appear to be relatively
simple methods of improving compliance among adolescents.
Assigning a health paraprofessional or research coordinator to

91
assess compliance throughout a study, improve communication,
and offer reinforcement for adherence, may also be beneficial.
The level of noncompliance in this study is probably
multi-factorial. The fact that adolescents were significantly
less compliant than the children is consistent with the
literature. Also, the majority of compliance research has
focused on children and adolescents with potentially fatal
illnesses such as cancer. The fact that the subjects in this
study were being treated for a relatively benign, although
aversive, problem (i.e., migraine) may have led to even lower
compliance rates. Typically, headache pain is treated by the
sufferer on an as-needed basis with over the counter
medications. Therefore, the idea of long term daily use of a
medication that has potential side effects may have also
contributed to low adherence. Finally, the chaotic nature of
many of the families in the study may have created
difficulties for the patients in their ability to maintain a
consistent schedule of administration. The incentive to
change their migraine situation compared to the negative
aspects of consistent medication may have not been great
enough to lead to good adherence.
The literature on adolescent and childhood compliance is
helpful in taking steps to increase compliance for treatment
and research purposes. In retrospect, several steps could
have been taken to reduce the level of attrition and improve
the value of the study. Closer follow-up with each of the

92
subjects and their parents, both in clinic and via telephone,
could have served to help the subjects feel more engaged in
the study, and to address any concerns they may have had at
any point. Through frequent contact and better education
about the medication and its side effects, the subjects and
parents may have been less likely to drop out and instead
communicated any problems they were having. This follow-up
was attempted at a lesser level, with reminders for
appointments being made by telephone, but failed to address
the broader issue of communication. Diffusion of
responsibility was also problematic in this study. Those that
created the study were not always the ones in direct contact
with the subjects, and therefore not responsible for follow¬
up. Others that had more contact, did not feel responsible
for conducting the follow-up either, resulting in a gap of
service. Assigning one individual specifically to conduct the
follow-up would have lessened the diffusion of responsibility,
and perhaps reduced attrition. Part of the follow-up and
original education could have been designed to engage the
parent in the study, particularly for adolescent subjects.
The issue of diffusion of responsibility most likely operated
at this level as well, with parents and adolescents feeling as
if someone else was responsible for their adherence. By
engaging the parents early in the study, this issue could have
been clarified with the families, with specific
responsibilities assigned to both adolescent and parent.

93
A methodological change could also have helped circumvent
the attrition issue. Most of the attrition occurred after the
randomization of subjects into three groups, after the month
of valproate treatment. A better design may have been to
randomize the subjects immediately after baseline testing,
thereby obtaining data from more subjects after only one
month, rather than three months when many had dropped-out.
This would provide a placebo control group as well as
carnitine data that was not available in this study. A cross¬
over could then occur after one month to obtain a cleaner
picture of valproate's effects. This methodological change
would not, however, remove the compliance problem as it
applies to drug level. This compliance may have been improved
by the methods described above, as well as employing more
frequent blood level checks and appropriate follow-up.
A final method of minimizing attrition is by making the
entire study less aversive. Reducing the amount of time the
subjects had to spend per visit, either by waiting for their
appointment or the time spent in the neuropsychological
testing, may have made subjects less likely to drop-out of the
study. Providing them with an incentive (e.g., monetary) may
also have helped reduce the aversive nature of the study and
decreased attrition.
Limitations of the Study
As has been alluded to above, the level of attrition in
this study created statistical problems that precluded testing

94
certain hypotheses. Specifically, those measures from the
third testing could not be adequately analyzed due to small
sample sizes. A simple correlation between blood level and
performance among the migraineurs failed to yield significant
findings. Again, the small sample size is most likely
contributory. This prevented an adequate use of a placebo
control group, although a normal control group helped to
distinguish practice effects. It also prevented assessing the
effects of the carnitine supplement altogether. However, with
the modest differences found between a therapeutic level of
valproate group and all other subjects, carnitine would not
likely have been able to have had a significant effect on
cognitive functioning.
The small sample size at baseline (i.e., 34 subjects) may
be criticized as being too small to reveal potentially
important results at baseline, thereby obscuring actual
differences. Although a power analysis may be suggested as
one method of determining whether the lack of findings was due
to a sample size too small for proper analysis, this is not
without controversy. There were statistically significant
findings using repeated measures analysis (i.e., an
interaction of testing time and group) for the Attention
domain. This suggests that the level of power was therefore
adequate, at least for this domain, to detect differences at
baseline.

95
Memory domains were also hypothesized to distinguish the
two groups after valproate was introduced, but failed to reach
statistical significance. To address the power issue for
these domains, it would be informative to examine the
differences in group means for the variables comprising these
and other domains (see Tables 3-1 and 3-2). Although they
failed to reach statistical significance, another level of
descriptive analysis would be to determine if the differences
fell within a clinically relevant range. This would help
ascertain whether there were actual, clinically important,
differences that failed to be demonstrated statistically, or
whether the differences were simply too small to be considered
relevant, regardless of the group size and statistical power.
A commonly used difference for clinical purposes is one
standard deviation. The only measure to reach this difference
was the PASAT on the second testing, which is part of the
Attention domain. Few measures meet the less conservative
criterion of one half a standard deviation difference. These
include measures from the Attention domain, and one measure
from the Memory Span domain. This latter measure was Digits
Forward on the second testing, with a difference of .60
standard deviations. The inclusion of Digit Span into a
domain with a pointing span was intended to separate short
term memory measures from memory learning measures, such as
Logical Memory. Theoretically, Digit Span could be included
with the other measures, but could also be included with the

96
Attention measures, because of the purported role of attention
in this measure. However, because of the controversy over
whether digit span taps attentional processes to the degree it
taps memory processes, isolating it into a more pure measure
of span was the decision made in this study. The significance
of the half standard deviation difference, therefore, is
unclear, but may argue for its inclusion with attention
measures. This also suggests that the lack of differences on
non-attentional measures is not due to a lack of statistical
power, but due to a lack of clinically relevant differences.
It was attention overall, then, and not memory, that was
affected by the administration of valproate.
Another potential drawback to this study was the choice
of neuropsychological measures employed. The Logical Memory
stories from the WMS were chosen because they purportedly are
fairly equivalent. Therefore, the same forms would not have
to be used repeatedly, hopefully minimizing practice effects.
However, all children regardless of group had significantly
greater difficulty with the second story than either the first
or third. After reviewing this story, it is apparent that the
language is not typical for children of this time period, and
as a result they continuously made intrusions and demonstrated
great difficulty encoding the story (for example, "liner" was
interpreted as an airplane rather than a ship by most
subjects, creating difficulty understanding the rest of the
story). This difference in level of difficulty may have

97
obscured results. Similarly, the Visual Learning test from
the WRAML had only one form, and although the stimuli are not
meaningful, a significant practice effect was also observed
for this test. Subject's performance increased dramatically
for the second testing, regardless of group, and may therefore
also have obscured results.
Conclusions
This study attempted to assess the neuropsychological
differences between children with migraine and the effects of
valproate when administered to this population. Despite the
drawbacks acknowledged of this study, several conclusions can
still be made. The first is that no apparent differences
exist between children with migraine and normal controls on
measures of memory and attention. The literature to this
point has not been able to decide the issue of
neuropsychological impairment in migrainous adults, and has
yet to address the same issue in adolescents. In general,
those studies that have attempted to correct for Type I errors
have failed to show differences. This study is consistent
with that research, and supports the findings for the
pediatric literature. The potential remains for adults with
migraine to exhibit differences in neuropsychological
functioning while adolescents do not. This would argue for
the long-term detrimental impact of the migrainous process.
Despite the lack of cognitive differences found, there do
appear to be higher degrees of internalizing behaviors as

98
measured by parent report than in the general population.
This finding is also consistent with the majority of work in
this area.
Based on the results from this study, valproate appears
to exert modest detrimental effects on attentional processes.
This effect is apparently not great enough to cause
significant problems with memory, however, which was not
significantly worse for those subjects with a therapeutic
level of valproate. Differential attrition, although not
statistically significant, favored the group assigned to
valproate plus carnitine supplement. The aversive side
effects of the medication may underlie this differential drop
out, but this conclusion is not statistically supported. The
potential impact of carnitine was not discerned from this
study due to the attrition. However, given the modest effects
of valproate, the impact would not likely have been large.
Future research in this area may use alternative measures
of attention and memory for confirming evidence. A more
restricted age range may also be of some benefit, particularly
in light of the fact that some of the measures (e.g., PASAT)
from this study did not have adequate normative data for the
younger subjects. Finally, reducing attrition with the
methods suggested above would allow for stronger analysis in
general, and specifically of valproate versus placebo, and
carnitine effects.

99
Despite the drawbacks of this study, the value should not
be discounted. There are no studies to date that have
examined the issues that were the focus of this study. The
potential efficacy of valproate for the treatment of migraine
must be measured in conjunction with the negative effects,
both physiological and psychological, of the drug. This study
suggests that, compared to other medications of the same
class, valproate exerts only minimal effects on attention.
This finding is important, because of the potential use of
valproate in an as yet unresearched population. The other
value of this study is the lack of demonstrated differences
between migraineurs and age-matched controls. This also has
yet to be documented satisfactorily in the literature. Future
research may serve to support these findings, as well as to
address the drawbacks through the use of better, more
sensitive, neuropsychological measures.

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BIOGRAPHICAL SKETCH
Kristin Fiano was born in Kenitra, Morocco, on June 17,
1965, while her parents were stationed there for military
duty. She has lived the majority of her life in Dunwoody,
Georgia, attending both elementary and high school there. At
the age of 20, she moved to Los Angeles, California, after
being accepted to the University of California. She spent one
and a half years at that institution as a psychology major
until transferring to Emory University in Atlanta, Georgia, in
January of 1987. She completed her Bachelor of Arts degree in
December of 1988 with a major in psychology.
After graduating Emory University, Kristin was accepted
to the Department of Clinical and Health Psychology at the
University of Florida, where she began in the fall of 1989.
She earned her Master of Science in 1992. She enjoys singing,
playing with her golden retriever Capi, playing racquetball,
rollerblading, and SCUBA diving with her husband. They plan
to transfer to Atlanta, Georgia, in July of 1994 to pursue
their careers.
109

I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the degree of Doctor of Philosophy.
Eileen B. Fennell, Chair
Professor of Clinical and
Health Psychology
I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the degree of Doctor of Philosophy.
Russell M. Baueir
Associate Professor of
Clinical and Health
Psychology
I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the degree of Doctor of Philosophy.
Bruce Crosson
Associate Professor of
Clinical and Health
Psychology
I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the degree of Doctor of Philosophy.
Rodrigué^
Julies
Assistant Professor of
Clinical and Health
Psychology

I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the deqree of Doctor of Philosophy.
Bernard Maria
;sociate Professor of
Pediatric Neuroloqy
This dissertation was submitted to the Graduate Faculty
of the College of Health Related Professions and to the
Graduate School and was accepted as partial fulfillment of
the requirements for the degree of Doctor of Philosophy.
August 1994
Dean, College of Health
Related Professions
Dean, Graduate School

UNIVERSITY OF FLORID^
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