Group Title: Cases Journal 2008, 1:67
Title: Cross-system effects of dysphagia treatment on dysphonia: a case report
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Title: Cross-system effects of dysphagia treatment on dysphonia: a case report
Series Title: Cases Journal 2008, 1:67
Physical Description: Archival
Creator: LaGorio LA
Carnaby-Mann GD
Crary MA
Publication Date: 39659
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Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
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Case Report

Cross-system effects of dysphagia treatment on dysphonia: a case
Lisa A LaGorio1, Giselle D Carnaby-Mann2 and Michael A Crary*1

Address: 'Department of Communicative Disorders, College of Public Health and Health Professions, PO Box 100174, University of Florida,
Gainesville, FL, 32610-0174, USA and 2Department of Behavioral Science and Community Health, College of Public Health and Health
Professions, PO Box 100175, University of Florida, Gainesville, FL, 32610-0175, USA
Email: Lisa A LaGorio; Giselle D Carnaby-Mann; Michael A Crary*
* Corresponding author

Published: 30 July 2008
Cases journal 2008, 1:67 doi: 0.1186/1757-1626-1-67

Received: I I June 2008
Accepted: 30 July 2008

This article is available from:
2008 LaGorio et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Traditionally, treatment of dysphagia and dysphonia has followed a specificity approach whereby
treatment plans have focused on each dysfunction individually. Recently however, a therapeutic
cross-system effect has been proposed between these two dysfunctions. At least one study has
demonstrated swallowing improvement in subjects who completed a dysphonia treatment
program. However, we are unaware of any evidence demonstrating the converse effect. In this
paper, we present a case-report of a 74 year old male who demonstrated improvement in selected
vocal parameters after completion of a dysphagia therapy program.
Dysphagia therapy resulted in improved laryngeal function in this subject. Results implicate
improved vocal fold tension with increased glottal closure. Further investigation into the potential
for this cross-system effect is warranted.

Swallowing and phonation represent different functions
of the aerodigestive tract that share a common subsystem.
Consequently, an injury or disease process that impairs
either of these functions has the potential to impair the
other. Traditionally, therapy programs adhered to a treat-
ment specificity principle addressing these dysfunctions
as separate concerns. However, recent evidence suggests
that a cross-system interaction may exist between them
[1], implying that the treatment specificity principle may
not be essential in rehabilitating either dysphagia or dys-
phonia. One study has demonstrated swallowing
improvement in subjects who completed a dysphonia
treatment program [2]; however, we are unaware of any
evidence demonstrating the converse effect.

Exploring potential cross-system treatment effects
between dysphagia and dysphonia is appropriate among
patients with head and neck cancer, as both disorders may
occur concomitantly in 44% to 47% of this patient popu-
lation [3,4]. This case-report documents voice improve-
ment during dysphagia therapy in one head and neck
cancer patient.

Case Presentation
A 74-year old, retired, white male with treatment refrac-
tory dysphagia following chemo-radiation therapy for
treatment of a T3N1MO base of tongue squamous cell car-
cinoma, enrolled in an experimental dysphagia treatment
research program at a university-affiliated speech and
hearing clinic. Nine months prior to initiating this dys-

Page 1 of 6
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phagia therapy program he completed 40 doses of radia-
tion therapy (7200 cGray to the primary tumor site and
5040 cGray to a secondary neck lymphnode) in conjunc-
tion with cisplatin chemotherapy. Following chemoradia-
tion he completed two separate courses of dysphagia
therapy. At time of enrollment in this dysphagia treatment
program, he received nearly all nutrition and hydration
via percutaneous gastrostomy tube. Daily oral intake was
limited to approximately two ounces of pureed foods.
Vocally, he complained of fatigue, pitch breaks, difficulty
being understood on the telephone, and reduced singing

He completed 15 days of an experimental swallowing
exercise program supported with transcutaneous neu-
romuscular electrical stimulation (NMES) [5]. Swallow-
ing exercise involved performing the effortful swallow
technique while ingesting a progressive hierarchy of liq-
uids and solids. NMES was delivered via the VitalStim'
NMES unit (Chattanooga Group, Hixson, TN). The Vital-
Stim device uses two pairs of electrodes placed vertically
along the midline of the anterior neck to supply the elec-

On treatment day five, perceptual changes in the subject's
voice were noted, prompting daily acoustic measurements
of three vocal parameters beginning on treatment day six.
Acoustic measurements of maximum phonation time
(MPT), pitch range (highest and lowest attainable pitch),
and habitual pitch while reading were obtained using the
VisiPitch IV (KayPentax: Lincoln Park, NJ). Each parame-
ter was measured three times before and after all therapy
sessions and during the three follow-up sessions. Mean
and standard deviation of the three trials were calculated
for each task. A total of 10 treatment and three follow-up
sessions were recorded.

Pre-, post, and follow-up swallowing function was evalu-
ated via standardized clinical, endoscopic, and vide-
ofluoroscopic evaluations including completion of the
Mann Assessment of Swallowing Ability (MASA) [6] and
the Functional Oral Intake Scale (FOIS) [7], as well as self
perception of swallow function measured via bisection of
a 100 mm visual analog scale (VAS). Each voice parameter
was analyzed using repeated measures ANOVA with Bon-
ferroni correction for multiple comparisons. When signif-
icant interaction or main effects were identified for any
voice parameter, Tukey pairwise post-hoc analysis was
employed. Of primary focus were comparisons made
between baseline vocal measurements (session 6) and
end of treatment measurements (session 15).

Endoscopic, perceptual, and instrumental vocal results
supported the existence of a cross-system interaction
between dysphagia rehabilitation and improved laryngeal

function. Baseline endoscopic examination revealed sig-
nificant supraglottic compression and a glottal gap during
phonation, while post therapy examination revealed
decreased supraglottic compression and glottal closure
during phonation. Perceptually, the subject reported that
his voice was louder, that he was able to sing in church
again, and that others reported being able to better under-
stand him on the telephone. Instrumentally, significant
between session main effects were observed in both MPT
(F(9,20)= 7.993, p < .001) and highest attainable pitch
(F(9,20) = 3.620, p = .008). Significant within session inter-
action effects were observed in habitual pitch [(F(9,20) =
14.215, p < .001)1. No significant effects were observed
for lowest attainable pitch (F(9,20)= 0.949, p = .513). Mean
scores for those voice parameters demonstrating signifi-
cant change within or across treatment sessions are pre-
sented graphically in Figures 1, 2, 3. Scores for baseline,
post therapy, and follow up measures for each vocal
parameter are shown in Table 1.

Since comparisons between the baseline measurements
(session 6) and the end of treatment measurements (ses-
sion 15) were of primary focus, post hoc analysis was
completed for MPT, highest attainable pitch, and habitual
pitch. Analysis revealed that mean MPT increased signifi-
cantly between session 6 and session 11 (p = .003) with
this increase maintained through session 15 and the three
follow-up sessions; mean highest attainable pitch
increased significantly between treatment sessions 6 and
11 (p = .004), and demonstrated a trend toward signifi-
cance between sessions 6 and 15 (p = .017) with the
increase maintained through the one-week and one-
month follow-up sessions, but not at six months post
treatment. Furthermore, the increase in habitual pitch
noted in session 11 was significant when compared to
both baseline session 6 (p < .001) and last treatment ses-
sion 15 (p < .001), but no significant change was noted
between sessions 6 and 15 (p = 1.00).

This patient demonstrated improvement in all swallowing
measures immediately after completion of the therapy
program (Table 2). Total oral intake increased from a few
bites of pureed or soft food each day, to three to five daily
meals of solid food including waffles, sandwiches, and
steak, while tube feeding simultaneously decreased from
8-9 cans daily, to 2-3 cans daily. MASA score increased 19
points; an increase of 10 points has been shown to be clin-
ically significant [6]. FOIS increased one level reflecting
the increase in oral diet and simultaneous decrease in tube
feeding. Lastly, the subject self-reported a 77 mm increase
in self-perception of swallowing ability on the VAS. Swal-
lowing improvements observed immediately post therapy
were not maintained through the 6-month follow-up due
to post-radiation changes, specifically radionecrosis of his
mandible and complications affecting his esophagus.

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Cases Joumnal 2008, 1:67

Maximum Phonation Time

--- Pre-Stim
-m- Post-Stim
-Linear (Mean)

6 7 8 9 10 11 12 13 14 15


Figure I
Maximum Phonation Time. The longest length of continuous phonation produced while sustaining/a/at a comfortable pitch
and volume. Each Pre-stim and Post-stim data point represents the mean of three trials of the task. The mean data point repre-
sents the mean performance during each session. The trend line represents the change in session mean score across the treat-
ment sessions.

Consequently, by the sixth month post therapy, nutrition
was delivered via full enteral feeding; oral intake was lim-
ited to occasional sips of liquid.

This case-report documented improvement in MPT and
highest attainable pitch in one individual who completed
a dysphagia therapy program. Although phonation and
swallowing represent two different laryngeal functions,
the improvements seen in this case report support recent
evidence that treating deficits in one function may result
in cross-system effects on the function not being actively
rehabilitated [1].

One interpretation from this case is that this dysphagia
therapy program improved laryngeal muscle functioning.
Since the dysphagia therapy included swallowing exercise
paired with concurrent transcutaneous electrical stimula-
tion over the larynx, either, or both of these treatment
components may have resulted in improved laryngeal

function. Swallowing exercise incorporated the "effortful
swallow" technique which has been shown to prolong
elevation of the larynx pre-swallow [8], and increase dura-
tion of laryngeal vestibule closure during the swallow [9].
The cumulative effect of repetitively producing an effort-
ful swallow in combination with advances in the oral diet
may have improved laryngeal muscle function during the
therapy period. Conversely, reducing oral intake during
the follow-up period may have led to a muscular detrain-
ing effect and subsequent regression in laryngeal muscle
functioning necessary for maintaining higher pitch levels.
Furthermore, application of transcutaneous electrical
stimulation directly over the larynx likely facilitated con-
traction of the superficial cricothyroid muscles. Enhanced
contraction of these muscles would result in increased
vocal fold tension and improved glottal closure.

Timing of the observed vocal changes supports the impact
of the treatment program on laryngeal functioning. Voice
changes were initially noticed at the end of the first week

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| 10

. 6




Cases Joumnal 2008, 1:67

Highest Attainable Pitch

- Pre-Stim
- Post-Stim
-Linear (Mean)

6 7 8 9 10 11 12 13 14 15

Figure 2
Highest Attainable Pitch. The highest attainable pitch produced without straining, while sustaining/a/in an upward glissando.
Each Pre-stim and Post-stim data point represents the mean of three trials of the task. The mean data point represents the
mean performance during each session. The trend line represents the change in session mean score across the treatment ses-

of dysphagia therapy. Next, significant increase in all voice
parameters was noted at session 11, a time point corre-
sponding with an increase in therapy program difficulty;
e.g., increase in laryngeal exercise. Last, deterioration in
vocal function noted at six months corresponded clini-
cally with a decline in swallowing function, possibly
reflecting a decrease in laryngeal maintenance exercise
associated with a reduction of swallowing activity. When
the timing of improvement and decline in voice character-
istics is considered in conjunction with the improvement
and decline in swallowing function, one can speculate
that the combined effect of intensive exercise and NMES
contributed to an underlying increase in laryngeal muscle

This case-report raises important clinical questions regard-
ing treatment effects which must be tested in future con-
trolled studies. Future studies of potential cross-system
effects should include replication in larger samples, across
different diagnoses, with appropriate control conditions.
Appropriate controls would include assessment of respira-
tory capacity before/following treatment, separation of

exercise vs. NMES effects, and comparison to traditional
voice therapy techniques.

To our knowledge, this report is the first to document
improvements in voice function during dysphagia ther-
apy, supporting emerging evidence for a potential cross-
system rehabilitative effect between dysphagia and dys-
phonia. The pattern of change observed in this case sug-
gests a positive impact of intensive dysphagia therapy
combined with transcutaneous NMES on laryngeal mus-
cle function. Observations made in this case report sug-
gest a new and interesting program of clinical research.

List of Abbreviations
NMES: Neuromuscular electrical stimulation. MPT: Maxi-
mum phonation time. MASA: Mann Assessment of Swal-
lowing Ability [6]. FOIS: Functional Oral Intake Scale [7].
VAS: Visual analog scale. ANOVA: Analysis of variance.

Competing interests
The VitalStim device and all electrodes used to deliver the
electrical stimulation were supplied by the Chattanooga

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Cases Journal 2008, 1:67

Habitual Pitch, Reading

6 7 8 9 10 11 12 13 14 15


- Pre-Stim
- Post-Stim
Linear (Mean)

Figure 3
Habitual Pitch. Subject's habitual pitch produced while reading the first sentence of the Rainbow Passage. Each Pre-stim and
Post-stim data point represents the mean of three trials of the task. The mean data point represents the mean performance
during each session. The trend line represents the change in session mean score across the treatment sessions.

Group (Hixson, TN). At the time of this study, Dr. Crary
was the recipient of an educational grant from Chat-
tanooga Group to support general research efforts in this

Authors' contributions
LL treated the subject, analyzed the data under GC-M's
supervision, and wrote the draft of the manuscript. GC-M
and MC developed the treatment protocol, conceptual-

ized the study, supervised the data analysis, and edited the
manuscript. Additionally, MC completed baseline and
follow-up dysphagia evaluations and supervised LL (a
PhD student) in all aspects of the case study. All authors
read and approved the final manuscript.

All procedures used in this experimental dysphagia treat-
ment protocol were approved by the local Institutional

Table I: Average Performance for Each Vocal Parameter at Baseline, Post Treatment and During the Three Follow-up Sessions.


MPT (sec)

Highest Attainable Pitch (Hz)

Lowest Attainable Pitch (Hz)

Habitual Pitch (Hz), Reading

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- 150



Session 6


Session 15


I-Wk f/u

(1 14.30)

I-Mo f/u


6 Mo-f/u


Cases Journal 2008, 1:67

Table 2: Swallowing Outcome Measures

Swallowing Measure Pre Therapy Post 6 Month
Therapy Follow-up

FOIS 2 3 2
MASA 176 195 189
VAS 15mm 92 mm 18 mm

Review Board. The subject signed an informed consent
prior to initiating the dysphagia therapy protocol.

I. McFarland DH, Tremblay P: Clinical implications of cross-sys-
tem interactions. Semin Speech Long 2006, 27:300-309.
2. El Sharkawi AE, Ramig L, Logemann JA, Pauloski BR: Swallowing and
voice effects of Lee Silverman Voice Treatment: a pilot
study. J Neurol Neurosurg Psychiatry 2002, 72:31-36.
3. Carrara-De Angelis E, Feher O, Brandao Barros AP, Nishimoto IN,
Kowalski LP: Voice and swallowing in patients enrolled in a lar-
ynx preservation trial. Arch Otolaryngol Head Neck Surg 2003,
4. Nemr NK, Brasilino de Carvalho M, Kohle J, Capatto de Almeida G,
Rapoport A, Scheffer RM: Functional study of the voice and
swallowing following supracricoid laryngectomy. Rev Bras
Otorrhinolaringol (Engl Ed) 2007, 73(2): 151 -155.
5. Carnaby-Mann GD, Crary MA: Adjunctive neuromuscular elec-
trical stimulation for treatment refractory dysphagia: A
phase I case series report. Annals of Otology, Rhinology & Laryngol-
ogy 2008, I 17(4):279-287.
6. Mann GD: The Mann Assessment ofSwollowingAbility Clifton Park, New
Jersey: Singular Thomas Learning; 2002.
7. Crary MA, Mann GD, Groher ME: Initial psychometric assess-
ment of a functional oral intake scale for dysphagia in stroke
patients. Arch Phys Med Rehabil 2005, 86:1516-1520.
8. Bulow M, Olsson R, Ekberg O: Videomanometric analysis of sup-
raglottic swallow, effortful swallow, and chin tuck in healthy
volunteers. Dysphagia 1999, 14:67-72.
9. Hind JA, Nicosia MA, Roecker EB, Carnes ML, Robbins JA: Compar-
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