<%BANNER%>

The Nature and Prevalence of Alexia in Aphasia

Permanent Link: http://ufdc.ufl.edu/UFE0022185/00001

Material Information

Title: The Nature and Prevalence of Alexia in Aphasia
Physical Description: 1 online resource (32 p.)
Language: english
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2008

Subjects

Subjects / Keywords: alexia, aphasia, reading
Communication Sciences and Disorders -- Dissertations, Academic -- UF
Genre: Communication Sciences and Disorders thesis, M.A.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: The purpose of this study was to describe the prevalence and nature of alexia in individuals with aphasia and to delineate types of errors produced by individuals with phonologic and deep alexia. Forty-one individuals with aphasia and twenty-nine controls performed an oral reading task of real word, pseudohomophone and nonword stimuli. Results showed that the prevalence of alexia associated with aphasia was found to be 80.5% and the most predominate type of alexia was phonological/deep. Predominate error type produced by alexics was phonologic (p= 0.0004) lending support for the simultaneous activation hypothesis. Further, regarding stimuli type, regular real words were read more accurately than irregular words which were in turn more accurate than pseudohomophones and nonwords. Finally, we found a significant covariate effect of years of formal education and reading accuracy both within and across all categories and groups (p= 0.0085).
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Thesis: Thesis (M.A.)--University of Florida, 2008.
Local: Adviser: Kendall, Diane L.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2008
System ID: UFE0022185:00001

Permanent Link: http://ufdc.ufl.edu/UFE0022185/00001

Material Information

Title: The Nature and Prevalence of Alexia in Aphasia
Physical Description: 1 online resource (32 p.)
Language: english
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2008

Subjects

Subjects / Keywords: alexia, aphasia, reading
Communication Sciences and Disorders -- Dissertations, Academic -- UF
Genre: Communication Sciences and Disorders thesis, M.A.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: The purpose of this study was to describe the prevalence and nature of alexia in individuals with aphasia and to delineate types of errors produced by individuals with phonologic and deep alexia. Forty-one individuals with aphasia and twenty-nine controls performed an oral reading task of real word, pseudohomophone and nonword stimuli. Results showed that the prevalence of alexia associated with aphasia was found to be 80.5% and the most predominate type of alexia was phonological/deep. Predominate error type produced by alexics was phonologic (p= 0.0004) lending support for the simultaneous activation hypothesis. Further, regarding stimuli type, regular real words were read more accurately than irregular words which were in turn more accurate than pseudohomophones and nonwords. Finally, we found a significant covariate effect of years of formal education and reading accuracy both within and across all categories and groups (p= 0.0085).
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Thesis: Thesis (M.A.)--University of Florida, 2008.
Local: Adviser: Kendall, Diane L.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2008
System ID: UFE0022185:00001


This item has the following downloads:


Full Text
xml version 1.0 encoding UTF-8
REPORT xmlns http:www.fcla.edudlsmddaitss xmlns:xsi http:www.w3.org2001XMLSchema-instance xsi:schemaLocation http:www.fcla.edudlsmddaitssdaitssReport.xsd
INGEST IEID E20101109_AAAACF INGEST_TIME 2010-11-09T22:04:36Z PACKAGE UFE0022185_00001
AGREEMENT_INFO ACCOUNT UF PROJECT UFDC
FILES
FILE SIZE 50084 DFID F20101109_AABNJD ORIGIN DEPOSITOR PATH wilson_j_Page_12.pro GLOBAL false PRESERVATION BIT MESSAGE_DIGEST ALGORITHM MD5
578640654922bc0b2ebb078cf9c4a768
SHA-1
1a606c4aebf51d08b724be8ab615d2fc1b821f88
7111 F20101109_AABNKX wilson_j_Page_31thm.jpg
6ad8bee92a4184b0b7444d7cb023a50c
da8864e87c858ee6c571649ebf8dad941b393e6e
80457 F20101109_AABNGH wilson_j_Page_26.jpg
71b1a77eb45c9255904f7a845b30563d
30332c029df98e11ddd6ea8cdacaa4931b065bf4
54168 F20101109_AABNJE wilson_j_Page_13.pro
8b24f562d9b1244ecc0f04f75c95a7a3
3caa870d3930cb5db56c1f18757148a578ccb168
18898 F20101109_AABNMA wilson_j_Page_08.QC.jpg
5ccd4347695fe6850677b1fd69621fec
b00ebc7fe7074986abbce4b811286987453a481b
26370 F20101109_AABNKY wilson_j_Page_31.QC.jpg
c857fc3c3eb0fe151c64963f094d2e0e
47a794f62127aba38e0e2c5ec3d0180c24f55a7f
87979 F20101109_AABNGI wilson_j_Page_27.jpg
47cf71ec8bee5f139c027c906714d0e8
a92de6190330cedab1d2ec44add683b3d4f466ad
50851 F20101109_AABNJF wilson_j_Page_14.pro
29e89fd5cff13e627c690ee4ac6262bb
6e536446a6a7704cef182e022623da9b8fc32407
26687 F20101109_AABNMB wilson_j_Page_09.QC.jpg
b63e548cc6d966702464a6b69c45388a
0139bcb5a7a380dea2c90257e0df5e417b7f5f01
7456 F20101109_AABNKZ wilson_j_Page_15thm.jpg
1353d279fd47c77733d79510584f7010
52969320d291dd73c9d4a9fe02a7eb24117bf724
85281 F20101109_AABNGJ wilson_j_Page_28.jpg
c01d5dc4e6491ecf6b940cd2d0abf827
fdcfa8fa30f3d1c22b7ff7bb9a0f9d2de0b4ff11
54927 F20101109_AABNJG wilson_j_Page_15.pro
fdee3057159d2d7e04a21030c3c76091
0772eb60cc54857eb6685fcb270e9563a0bff291
7374 F20101109_AABNMC wilson_j_Page_09thm.jpg
992c79ccbbe4a98b3304127159282b15
8116bc5c829d1fff6fc4bfe0e5ffe7cfb08cb369
45357 F20101109_AABNGK wilson_j_Page_29.jpg
0b5857434686b9010ff39a13c455278a
c799a68b6d8d7c5227e14a2e23574479c9d4d8df
14085 F20101109_AABNJH wilson_j_Page_16.pro
a5faf3b202cbb41fca694155614b0871
250a1306fb1af2f463c5e7134549dea663523af3
5902 F20101109_AABNMD wilson_j_Page_10thm.jpg
5b99b19388db2bebb199fad678c7da83
d320c2e11b90f753cb3efe673f0020809d4bbf7a
92155 F20101109_AABNGL wilson_j_Page_30.jpg
66f70385e9bd1107f3ef3e153dc2d4a9
7e20de25ecd510d21a7cd18d78ddc1eaed3ace64
15846 F20101109_AABNJI wilson_j_Page_17.pro
6ff0621efb5b553246bdc49b1b4a70d7
318f31b852dafdf5116d53355cfae796123406d3
25641 F20101109_AABNME wilson_j_Page_11.QC.jpg
518576b45c4bf48f6ce14c16397d6d72
ca4926cef37f6b34a3d422f19c3dfd182b82a669
90970 F20101109_AABNGM wilson_j_Page_31.jpg
3c40bb01f6163e84815ccf25436f97fe
c532363410958a54d9229be0c903c3fef0627563
45493 F20101109_AABNJJ wilson_j_Page_21.pro
24640ff8b432e4ba91d3973eacfd332a
a4c28e1e7b8189865fa9976cc1051680eb76ba7c
25968 F20101109_AABNMF wilson_j_Page_12.QC.jpg
d786f5f6023654021b2c78c360ce00c0
2391008ca74570e7743084c4e6523cb630c00963
58728 F20101109_AABNGN wilson_j_Page_32.jpg
84542d4da5f68629d1c86e057c8c4501
2f08d7d0bcc34261041b8b528cbe8dc96837c49a
7093 F20101109_AABNMG wilson_j_Page_12thm.jpg
dd30d6f0050a29cb436abdb6d06db302
abccedf38c59e4df1dcf38c727f0fa79530930c6
28782 F20101109_AABNGO wilson_j_Page_02.jp2
bdf74c9418103b0b2d8b026617d80534
b7f2183ca36fb887214d8438370849ef04b45276
7333 F20101109_AABNJK wilson_j_Page_23.pro
c4fcdc7f93539d53ed47e717828d7a22
4ef3ebe44496b54002d3fc41ed858452dd545807
7538 F20101109_AABNMH wilson_j_Page_13thm.jpg
1eef5bed9692269aa2c8e1705c6cb4dd
e6e75b36bfa76c0a42a8cc424756da507ab93241
18326 F20101109_AABNGP wilson_j_Page_03.jp2
a54140f867f832a7697366b5f03e7409
fd24633bcf1b24fdfaf44a5bb653c9fed7991423
21858 F20101109_AABNJL wilson_j_Page_24.pro
e1141af13b94661683efe3aeac466c84
25489a23f7e83a461a5c9a743505ae0a20890354
25828 F20101109_AABNMI wilson_j_Page_14.QC.jpg
f355ace1b29cb2c3f646c3d25dd4d4ab
95e0526c5f311d4a76d4319ca3b882bd995dec3a
250811 F20101109_AABNGQ wilson_j_Page_04.jp2
7cca9cccbf79c61cc34a25e66eb6f23d
39a8ca9cb78cdab0a04a23cb3e3eb569aec7487d
4217 F20101109_AABNJM wilson_j_Page_25.pro
71401ee1ab10bd36e473489bc040e425
0e468f63659c558c22e5dde79e95846fa61efeef
27088 F20101109_AABNMJ wilson_j_Page_15.QC.jpg
06dc7f5b7e44641d23797b645a9924f4
b60db39422906e3af567bfbf961e0d239c89e3cd
1051984 F20101109_AABNGR wilson_j_Page_05.jp2
9a035db3db0f66347a781a7ad3e229c7
c7436cb7d4bd1d782862d096ca594e718152deea
50020 F20101109_AABNJN wilson_j_Page_26.pro
3b0b60aba49ef766322c9057ad74ef6f
c5f971a6a0a4cbbb757a6b115861364d284bce74
2718 F20101109_AABNMK wilson_j_Page_16thm.jpg
0c1502b6f4c87feb442ec637dd501b56
7791cedf554fd921f61d13ba8f3a7c5a224ef509
352921 F20101109_AABNGS wilson_j_Page_06.jp2
3b6a00d0e5441baca3acc3ae08e65ce4
144aa930e0b736c66b7fb615839313b502f52037
56249 F20101109_AABNJO wilson_j_Page_27.pro
c12b9852ae9f1e89e9f3e11b4ab23f30
749d3ece2ba113b05e39b88f70533744298cad1d
3003 F20101109_AABNML wilson_j_Page_17thm.jpg
998d386964ab6ad1ea46cff51a73703b
9fd1956bdb1c306b99fae59cc88c56d72c8cf1c6
937520 F20101109_AABNGT wilson_j_Page_10.jp2
9a322cda9ff98f0f1657f64266281182
cc7a5a7d034c3e8c839196b151a25d80168f040a
53518 F20101109_AABNJP wilson_j_Page_28.pro
0b334eda5ac9ba247c7f036b6738411f
25412ed76d0a496a95d5e02181496a052ba4916d
24075 F20101109_AABNMM wilson_j_Page_18.QC.jpg
ec209f574315ed265923dc9389e18715
7a2f65c52465a794ea6ee4ba476659da309f7332
17302 F20101109_AABNFA wilson_j_Page_19.pro
b4c7289bd12b96b9747352a83bcff694
6026c143f294914143b66dcc6e991cd4a46dc138
1051944 F20101109_AABNGU wilson_j_Page_11.jp2
a181c8ca4107829fa7b9d2c7b3d6ca89
aceadc4c98bc5eb52b2e7cac68aff8d12a5521e9
25613 F20101109_AABNJQ wilson_j_Page_29.pro
e5c8c85b381b1079c34fee25fbd6a075
326c35521f82641fff8c02dc0a9f7b8e7a628e43
1333 F20101109_AABNFB wilson_j_Page_03thm.jpg
89ee90f18d99836115a1a3633839d94e
2b12dc23ad8dada017ff88dd085ce528631f007b
1051946 F20101109_AABNGV wilson_j_Page_12.jp2
cf469b071e78aa777d56fe0a53854b5e
1ccaef4c429f06a86af9c4e7d13ec03901af57a7
59400 F20101109_AABNJR wilson_j_Page_30.pro
d241472ce573b62c69a423ba98a0d8b2
0ecb67337e54ed6778bce630a11969d22a71959d
6482 F20101109_AABNMN wilson_j_Page_18thm.jpg
7a2f21a1d4b48d9e799e0bb9b9de9649
9a2921985efd08947a6f33a842cf0482dca9e5df
1051907 F20101109_AABNGW wilson_j_Page_13.jp2
63a5dcdeba3891044de703344fb0ae60
8b59b8f124099704f4a7683310d22959af35bd04
55352 F20101109_AABNJS wilson_j_Page_31.pro
0006ce4d669bad12d4b05297eb04ee08
c1e429a0d3d5bdd710a5f51ecc595aeb1b95b080
10048 F20101109_AABNMO wilson_j_Page_19.QC.jpg
ad2a18d8384a5e5b8e89b417a53c9613
c91bfbbef0335e114a68a825f9f2481c0475c790
18385 F20101109_AABNFC wilson_j_Page_32.QC.jpg
765c71c41fa6ba0dca007110670c34c7
3d1dff6198201ac3b579ebd031c43c72f04304bd
1051985 F20101109_AABNGX wilson_j_Page_14.jp2
e466b92bb6959fbba22ad36e927bc2fa
54f6948c79160e5cb9162add94540c85d45ac022
34308 F20101109_AABNJT wilson_j_Page_32.pro
3b82765be8ec2481398cd284c9b0ef2a
2de1ea96c47c94ab12b6f15852746e4583c48285
3276 F20101109_AABNMP wilson_j_Page_19thm.jpg
d4c6081ebe9d5c00f8e5cf6f37d71ea3
efe09c3ecf1978a394973cac6542cef3181cf4ae
869 F20101109_AABNFD wilson_j_Page_24.txt
5e22ae381aa338109f4c4adcf8885828
252cd7ed4cdea057e294da37c9b95b04d85934ea
1051971 F20101109_AABNGY wilson_j_Page_15.jp2
26cf7afa6a7c7416671ec1f994bee0c2
76199dd7eed4fb604aa5919d0668ffaa86b04468
417 F20101109_AABNJU wilson_j_Page_01.txt
993bf8ca370fd58bd4325f8395eb0656
b640c23f68f912343edfd7ce94b59a45bcc2f1db
25232 F20101109_AABNMQ wilson_j_Page_20.QC.jpg
fa635949942666f368ba554488faed90
76b6459b78d0bcf709f4a2a961f4622b748e0d7b
5755 F20101109_AABNFE wilson_j_Page_22.pro
65ae3343c2139043e17fcf3009716b71
b718c734a028d6734c849de49bbf211e08d5744f
25271604 F20101109_AABNIA wilson_j_Page_13.tif
c05d12e68de5f28cbaaed646308f54fd
eae32457456b2d9e3a6e874efc549221d8532012
88 F20101109_AABNJV wilson_j_Page_02.txt
914242ee2bf03256bf467d30f944279a
3e0febb44fcaee0aa01f2b311bc49ef651d8786a
5943 F20101109_AABNMR wilson_j_Page_21thm.jpg
7d17e371be12decaefffa367cc2ddc93
9db26f0ced2371dcebd62a878b018c59f5152b6e
50581 F20101109_AABNFF wilson_j_Page_20.pro
0be9d67eb811e9a5842a22c987605947
0db00a59c072c17d3cbf799d58a0dbfdb17e31b6
F20101109_AABNIB wilson_j_Page_14.tif
87a67cc7c408380abb1e07ceaf411b71
03581655e1dd2fe23b2cf5a42314b458b8880a30
300824 F20101109_AABNGZ wilson_j_Page_16.jp2
b85961a2554257fd6b6985379c14a8f6
9d53252395170f66c22621a5eb4ce5cbb09f4441
75 F20101109_AABNJW wilson_j_Page_03.txt
97e28da1de6e869800388cf23f542494
a9ee1e3fda5553d3cde1a4aaf40839f73370c133
5392 F20101109_AABNMS wilson_j_Page_22.QC.jpg
3c66bfb9c604a2f380ed3d865e24f833
d842ca42963107be3c3fb97f1e8163919a1c70e6
F20101109_AABNIC wilson_j_Page_15.tif
8dcc950df5d6e5ade313d0b6b25c326d
7f829799a0f4157d8147a801836492b7798ef4b2
10318 F20101109_AABNMT wilson_j_Page_23.QC.jpg
5ae33658c615962e7c73ed551d5800e0
66419b4f2016a72fdbc8ea50ee3bae026b7601e1
38045 F20101109_AABNFG wilson_j_Page_17.jp2
cd8a78f1be0df56add8357826e675a06
a7b35e5a939c8902386ddb09c47d2f6ed054b65f
F20101109_AABNID wilson_j_Page_16.tif
6a166fc479040dfe6c1f6b6bd19c2ecf
fe66023eef34e26e7674a2d0dbb65851cab03949
462 F20101109_AABNJX wilson_j_Page_04.txt
e319c162df8d192c21202465c0383bea
4f98e700913fa2df45d84d5f9117a7872a48c040
11443 F20101109_AABNMU wilson_j_Page_24.QC.jpg
8d8ff50cb4d41cdd0dbbbf977dca4d69
da8e5ea136023f48ae90b5adc95254d74b6d7049
40382 F20101109_AABNFH UFE0022185_00001.mets FULL
42c5f9f48277a13222b2f1914489e0ad
8f66e35372d8c5eb1aa9f487725ab8992f3d4e81
1053954 F20101109_AABNIE wilson_j_Page_17.tif
bb14194ac9fefe6deb7a44c40d788d0f
8d8c011083d024c2129b5a7470cec66c205dc384
7025 F20101109_AABNLA wilson_j_Page_01.QC.jpg
380799eedfe1f9782322bca8512af7e6
27c4ba88ee25a81b4813078c675ddf9ed728a37d
364 F20101109_AABNJY wilson_j_Page_07.txt
0ec6840db668ffa37cb61896ac2b8faf
bd0154b31a5ca0aa40a51c4690d4381b3e534d8b
3189 F20101109_AABNMV wilson_j_Page_24thm.jpg
a77efda5a92213a517352594f3049af4
b9ca1ccab5f9f8733a6e340d23bd57bf831e2bb5
F20101109_AABNIF wilson_j_Page_18.tif
b9939c52cdd25cf730656481dd4400e1
f5f979e295a83dcc3e9320f13f0691495e6402f5
8852 F20101109_AABNLB wilson_j_Page_16.QC.jpg
1a8fc7f88ff455969116fccbc69ba223
e3692630d0c140e7f5b06738849c1c81b8189536
1521 F20101109_AABNJZ wilson_j_Page_08.txt
932d6d533f07de9fe4085dd47a1c7b54
f54b27f9b4291118a31ca834e5545d4fdabfae8f
2524 F20101109_AABNMW wilson_j_Page_25thm.jpg
cea004121f71ae8dab5d0c0b7da294b7
ffa1cc766b60ff2b9062b4587322fbd25bc6e7ae
F20101109_AABNIG wilson_j_Page_19.tif
942b9beeadac02a43b6bfee1c8dbf753
99fe9b9ced03ac17299349b1f33ac3af9a31c716
21574 F20101109_AABNLC wilson_j_Page_10.QC.jpg
8b384455a17364ab1f2439393d937b6c
010d8fc73d8dc10293b831ba6f68465bc7450448
7178 F20101109_AABNMX wilson_j_Page_28thm.jpg
c54db9212d03151448b02d8d84f254ed
f606043dff797d1fa387fbd95055bb53eefa76ee
22226 F20101109_AABNFK wilson_j_Page_01.jpg
90495ae0c3d74af27aa271430b40367d
087e9b53700147877b0910d1a346c6cdf6712e2c
F20101109_AABNIH wilson_j_Page_20.tif
8862bbb4d4f24dcfbfbe87d53ad4313c
76cbac046abee54042e7943b08b27855bf477cff
24938 F20101109_AABNLD wilson_j_Page_26.QC.jpg
14445f3a48637b2527c6285f834c25f1
432360a4526c5022865394f439a19b37ae7e8116
14735 F20101109_AABNMY wilson_j_Page_29.QC.jpg
21bb972f0c129c54306804ceecb60b61
0f7f8b7b3e38fbcac655c4521cfe758bde39a1c6
10190 F20101109_AABNFL wilson_j_Page_02.jpg
678e0d669a9e009758e88244fb41336c
9076c7f26107a102755055ef75b47204fad812e2
F20101109_AABNII wilson_j_Page_21.tif
cc73d0525e7dbdaf0aa57be320d0c2dd
cfd7b285f0ed15bca15c11cf79b62fa0c8f15634
7264 F20101109_AABNLE wilson_j_Page_04.QC.jpg
b394e02a487b405bbad0647ea8ca1f39
42af5dad090546a1eabcf2ef30ca473d189fc852
26831 F20101109_AABNMZ wilson_j_Page_30.QC.jpg
b8398c64f30051139b35d7f94ed920f5
651fb5170bfe2eb335c37e8aeb0714f7f07e0534
9475 F20101109_AABNFM wilson_j_Page_03.jpg
c48ac794c6f86e24028c10d7f536acb1
c2f7f19311df6bdff592791f6d559621623dfd99
5887 F20101109_AABNLF wilson_j_Page_07.QC.jpg
7a8b0b7490711c7697e79289d7084ded
517fc39e14c04b2905be18af6060ef4b25941ba5
23976 F20101109_AABNFN wilson_j_Page_04.jpg
a1a64e9b07523be6152a8c98c5f18d2d
a4a11a039b3a603d3e6cf1137a03cfeb12726e53
F20101109_AABNIJ wilson_j_Page_22.tif
d772d2a22f2d342fa21d0ea8dbc4ebfb
c4638911e9425902236a5a65e5c9707c8974b45e
2129 F20101109_AABNLG wilson_j_Page_06thm.jpg
abe2bba880d78981a3dec648c2c0ff41
2254c8d53f666baa3e9b939a856d17708ec36dac
66697 F20101109_AABNFO wilson_j_Page_05.jpg
2c58f24b8220322a34cdc7621b3ba530
c027d9db570741e1abbddbfb3044f07ef4bfd8cb
F20101109_AABNIK wilson_j_Page_23.tif
aa5837e1913658e16af569bf69d7b154
9512da36d4f98de7a870ce26411333bf38cdd173
7154 F20101109_AABNLH wilson_j_Page_20thm.jpg
ba1d7916b1b9695528561eca8146c7ca
65948e4928966aa14a3fdb4d91c223d5b64003f0
19840 F20101109_AABNFP wilson_j_Page_06.jpg
18c24fb3ba3e885389dc347363730b36
08aeb290f53d0a97b1d7cfde01af8e86b5127569
F20101109_AABNIL wilson_j_Page_24.tif
1cd104ac9079aa37bf6a8a11c214e6ad
6eba46ffd559288e28ce519cf05616d6b773cc12
1926 F20101109_AABNLI wilson_j_Page_22thm.jpg
c7c0a46793f3ec97d917448c9a1f72f8
d37d1a310bcb40830eb7bb4f5ea0d4f52aed25fd
18935 F20101109_AABNFQ wilson_j_Page_07.jpg
672f4498ee9301c596b379ba0745e60e
f15671a9ae800d9948156853a18859f4e1917d24
F20101109_AABNIM wilson_j_Page_25.tif
0c2709cbef5782ed73fe59a2b6c0255c
9a763b5b46676d506e6166bdad1d4a9b670a64b1
26965 F20101109_AABNLJ wilson_j_Page_13.QC.jpg
80dbfb3ca5b414c90fb254dbb6683c78
cd616970ef3f4b4d405625c87f9c6344b6a05e9c
59532 F20101109_AABNFR wilson_j_Page_08.jpg
68ec757388b2f98f0d64d06bc9a1d3c8
b888591e2bc08250951e932ccb6bdf89197ad351
F20101109_AABNIN wilson_j_Page_26.tif
0f80819e92a99d1c5c91bb9f688e80f1
f2fda3f1dd7fd9269778ac6c35f7e0e5301a2e8a
6799 F20101109_AABNLK wilson_j_Page_26thm.jpg
1816ffe0c3d114e7594ff84737def05e
cad399a0c66268c960e62d7e8f6a11489ca255da
84744 F20101109_AABNFS wilson_j_Page_09.jpg
443cebae688b9381f078722e2b209035
ce63b75e1582ad03d616958fc195d42b3256dc8c
F20101109_AABNIO wilson_j_Page_27.tif
d8c0f2b8ffa44cb7ba85e81e4911e9e9
a9728efcfb3890f45a986a7c72be75caf5070333
6977 F20101109_AABNLL wilson_j_Page_14thm.jpg
256ba09096f0bc047db6968981237c85
4baa587c877b5223186cbc49fb97dccb732c76b8
67470 F20101109_AABNFT wilson_j_Page_10.jpg
a73d2948a8e6c2d81a19c0b91e85315e
0d3768adee9843f50a0d380b8f9c760fa50f78fa
F20101109_AABNIP wilson_j_Page_28.tif
14d35730b2c6544a2341f687b89efe82
fe9a3a77b3a5bf031576e6befa70fa01b4309ffe
80041 F20101109_AABNFU wilson_j_Page_11.jpg
61f2a1481713e9e68fb2af6104c4b68d
9b6e5300da8ca28cf774d36bb23c29d1561e7705
F20101109_AABNIQ wilson_j_Page_29.tif
60b68dac4f38e4cc92547408d7bc90a6
949682df3863aff92b9afddff9f6fc1d1d066810
6982 F20101109_AABNLM wilson_j_Page_11thm.jpg
a77d1ff9774f77b29c7aa85fea87ecfd
1298204ec4db92b3932b61bc4f43047a8c58bf7f
87024 F20101109_AABNFV wilson_j_Page_13.jpg
44130d7116ea7a56dd569c6cb91cccac
5713c9e9aaa070dba0e4426cab8e7f839dd9708e
F20101109_AABNIR wilson_j_Page_30.tif
d08819a21bf53b651769082ec22c403c
8927882e05f504db161c2b72f3a1ff4ca5a0b996
2099 F20101109_AABNLN wilson_j_Page_07thm.jpg
9e02a050112bc6d30dfe787b04d8ebab
81da26c6c336c3713806d32d3546bbae06d604b9
81678 F20101109_AABNFW wilson_j_Page_14.jpg
f3a6ba0eb3bbc8e1fd24e73889b0b7ff
fdab89fe30a9d9197b0748e883c61bfdf1564123
F20101109_AABNIS wilson_j_Page_31.tif
d15c81e85c3d4712f0e40d9daaf9e5b3
1aa233cdb70443181a467cb57abfd5b037d27f8d
27915 F20101109_AABNLO wilson_j_Page_27.QC.jpg
c2f398aa339eafd82e1eab897af3fd8c
c1c140230c480b949f411dd0550bf4dd2593ef85
84718 F20101109_AABNFX wilson_j_Page_15.jpg
9fd8665eecc38740f3f061d4fd37192c
93f0c1207aa6c48eff8b707bca379a75e86513a4
F20101109_AABNIT wilson_j_Page_32.tif
579a67b66fe1d4f097085e852288ab11
f755ff3edb91acbdd7b9fe0420dbbba0089cf48c
4776 F20101109_AABNLP wilson_j_Page_05thm.jpg
f4548af04c5a6db95fbf3ff0e4e2baf0
26ace60f2ab961706fe0ec6b93a2ca9b30551949
110250 F20101109_AABNHA wilson_j_Page_18.jp2
b88fc4f75c60e279b1908dc11ac1e9db
b343d4b884404c5bcd7f9286c6dcd6f0c69354f5
30972 F20101109_AABNFY wilson_j_Page_17.jpg
7fb2ee499571c7133c7e4ba6e83df91c
d3b3407f4095397c3e67cc848ee011e927a838f7
7142 F20101109_AABNIU wilson_j_Page_01.pro
43b6ce516173dd244ee35fec1870ccf8
12b09a96770d4f80e4ec5dc4ed0bb564701c9848
9522 F20101109_AABNLQ wilson_j_Page_17.QC.jpg
2823159d7fa6270d86f6401776143b51
16b84d96822df4d14726787ac44c066e5035893a
41668 F20101109_AABNHB wilson_j_Page_19.jp2
40cf4040627d93770d0fe32667a15550
aaa17a79eaf1598c1e71b7f4e5e42438c95cdbc3
72560 F20101109_AABNFZ wilson_j_Page_18.jpg
6fa0113c41ab23dfb916563fbff4c1ff
026aa9c2bb99a3def58d2109c893882cff6886b5
985 F20101109_AABNIV wilson_j_Page_02.pro
4d1f8bae771ca77469398d80812cb305
ddd323c4c5f801f71a20982cef066c55a4de2485
5751 F20101109_AABNLR wilson_j_Page_25.QC.jpg
4001e9277d82850323ab02b9b075d2d4
9bd390a7bd10b84cd8d14aea8e0fb78473dae4fc
1051899 F20101109_AABNHC wilson_j_Page_20.jp2
95a39235b09b4d86d8e530c9e5beb301
b860d24bafad6c7455c0f786b5114c37206ac9f3
647 F20101109_AABNIW wilson_j_Page_03.pro
9d42757a79b3700a5aa675dddaac0bc9
dbb56b904b9dc7ac96de3e3bda6971f0e8a9ed27
7493 F20101109_AABNLS wilson_j_Page_27thm.jpg
db4b88a847e5495d7fab0f4f4362ffc1
0ffe36ae1531b369ec445932cbad92f1593ac7c4
18281 F20101109_AABNEG wilson_j_Page_05.QC.jpg
4ca6f583cb5abe11d8d9b7c17d770538
3708aa07d22dc8654835404c334f6341b3f69394
102488 F20101109_AABNHD wilson_j_Page_21.jp2
ddca748c8113a751daacb5ca592e02e5
73580639c31d9eb0589fd79f6b27c769070dc544
10639 F20101109_AABNIX wilson_j_Page_04.pro
5cd30c5854995ea638d33dbb98741009
9de5b48e2da2a53c01a36dc82dced7ca9dfef49a
7277 F20101109_AABNLT wilson_j_Page_30thm.jpg
fb666668599191f55df04cf4a073887f
3f6a4bec52ec2cb3f01465f4d22f7e5f9ffaa882
10656 F20101109_AABNEH wilson_j_Page_06.pro
254d7d6943cfac7771837d364a9ede3f
cf0f5e9eafa04f1e206429a0edf928f2e6107194
15869 F20101109_AABNHE wilson_j_Page_22.jp2
4a88cc68375f14a1671107d5709212d8
94ff3b585051234cc9a1d51cc6b3969a5cf5375a
2173 F20101109_AABNKA wilson_j_Page_09.txt
0c649dc3b0583ef79dc3c9f708df768f
4b7d4c10b79108108e7c2ba5f60df6a7cecfa5b4
63861 F20101109_AABNIY wilson_j_Page_05.pro
417d087a89c8edffce26e05dd9934bc9
e46f09ea564d05569311eb1941ebfa0f08c1b0f1
27305 F20101109_AABNLU wilson_j_Page_28.QC.jpg
cd5051cce9fb744f0b0c13d18aeb05ad
687b27db0a2f2fedf76ee20defba16baa3a4a44f
6177 F20101109_AABNEI wilson_j_Page_06.QC.jpg
be9671c062537560e9d5612a780114ba
4bc967bb7f7f4616a679da8b72f987236c66723a
368637 F20101109_AABNHF wilson_j_Page_23.jp2
b22aec9d09d2b291fbb2cee5f1c541b1
31afc9c26c3b3532d187c4d1be856b3a85222637
1664 F20101109_AABNKB wilson_j_Page_10.txt
2a8a93ee45b318b2cd713fd7217c489e
3c6d53cec8bd734e7bae09c75149c7d3f2b01fa7
8804 F20101109_AABNIZ wilson_j_Page_07.pro
dd1fcb318eb1bfba538c3997fa50b46c
8ae777b4bf765438ebca6aefaade6ecacb7bd5b1
51660 F20101109_AABNLV UFE0022185_00001.xml
e00cf6ff15b35c296396b7e11e4cb1c3
67386ca32153a5cdc3d86a9aab24beccbd5a65f0
49851 F20101109_AABNEJ wilson_j_Page_18.pro
0f22ca5cf10b734b12438a7fe5e4f8dd
68569095475b58766ddc3437553d24779f35a780
49859 F20101109_AABNHG wilson_j_Page_24.jp2
64fa5f063d6fcaab54e0523b9c9f726b
89e76c624ca675e2578d28103486b93ebd2eef02
2125 F20101109_AABNKC wilson_j_Page_13.txt
b0f01e6a0128f03ee9462951bbc730ba
f41cd076a52396b215ae3e9c51e734c311c5c2ac
3294 F20101109_AABNLW wilson_j_Page_02.QC.jpg
fe84324449708a2ae5d03c108cc729cc
44f8ca3d6c03de50baf4284a80c99c51e3b62f68
F20101109_AABNEK wilson_j_Page_10.tif
c7feeab4b1b603a1d44235e728317f2f
b8c56c14fdf66161e351badf9efa4a47dfeda763
121019 F20101109_AABNHH wilson_j_Page_25.jp2
cef02f454610d5e92f65950b1b1a679c
c93f7c25bec811f4f0bfa2c721600000c0ed413e
2036 F20101109_AABNKD wilson_j_Page_14.txt
1df70ef978347275950907126d7cd881
c4996ab27ad0e5655e493a38243c5af9ea4f9c87
1417 F20101109_AABNLX wilson_j_Page_02thm.jpg
dfcdceaf496f7af57ad8b9862d464540
da3513107594c9d5a562877488e8fc500ca2eb74
5267 F20101109_AABNNA wilson_j_Page_32thm.jpg
1562240f3f728c05280cbced9e60059e
c916602fc2d4bb5cafbb04f34f452acd5aade48f
211557 F20101109_AABNEL wilson_j_Page_01.jp2
562b74ea614c6bb5ee35e597e12e131d
29f8245e9140e16d4705f3c6432aad44b03a5737
2197 F20101109_AABNKE wilson_j_Page_15.txt
f1f5cddf8a8d7545261e46e1adac7ab2
43a21df514369965b0383ad2b4a9c082b4d92f46
3049 F20101109_AABNLY wilson_j_Page_03.QC.jpg
48c25b583a5e768f18b2c3dce450ede8
279495b59af0e648682ce7e1764c0055074e3c14
2791 F20101109_AABNEM wilson_j_Page_05.txt
7f91aa0caa2c5930ce44d311922f0a4d
fe411db3b9a96b43294b7825a93e83e10023c87f
1051973 F20101109_AABNHI wilson_j_Page_26.jp2
1628ee24e7cbee01a990d4a084f68f16
a8b90a4ceda29c6af70dad780e196977bef2f121
562 F20101109_AABNKF wilson_j_Page_16.txt
ceabd64bf3158b48c597ec930b0e525d
593421095023cb30b06aea7dfb8cf04c7e7c2795
2341 F20101109_AABNLZ wilson_j_Page_04thm.jpg
97705c0a472ebfa6d902645bab8be6cd
5a87e60f33ae07bcbb8e7ab1fd06c0ac5a7a65b3
493 F20101109_AABNEN wilson_j_Page_06.txt
835df01da2a2ae795fc6f9e8b3ce07e7
0cf8d1fc7ede5998faaa2729992ba4f45f610717
1051978 F20101109_AABNHJ wilson_j_Page_27.jp2
4ae41dbf9cd8cdefc008b7a57d82f73e
168c48466184fdb33a034c29bc31f5f82b38004c
645 F20101109_AABNKG wilson_j_Page_17.txt
4a4b0534517919e8cd5ae3a17e0b2585
0dcf7a4f288876d4cf129bd804874437ac468b3f
1051960 F20101109_AABNHK wilson_j_Page_28.jp2
93d3b47b1061cae96f43ebdd869e7f3e
d46c14f32f69f9bd75492c492ed5516f4e90eb83
2107 F20101109_AABNKH wilson_j_Page_18.txt
bf7866b066dfbf8132ed2608733ffa34
09af57a299bff49b47d888702e8e9231cb390c1b
327532 F20101109_AABNEO wilson_j_Page_07.jp2
5f215e898457b1db5e0c03feb7a5bc63
515fb0961fd236f0ad6152ebbf5cc3d74367aa67
575111 F20101109_AABNHL wilson_j_Page_29.jp2
9190b06a8b8ffb3bd3540a03072bb5ca
7e8877c014b55191d34d75b7acf726236a9e69ad
734 F20101109_AABNKI wilson_j_Page_19.txt
5854ca471fb104b12a6ec09cb7ecc453
57247a070232ac5bf7fc21b05635b8e83426f8b3
1051980 F20101109_AABNEP wilson_j_Page_09.jp2
2865b4cf6b3fe6175070dc75bed24545
76864ead5fb77255b9b9cb003931cd1c9f008f52
2138 F20101109_AABNKJ wilson_j_Page_20.txt
0e8412237f6080cd2632c49826595570
bbd842732f92b27a964776fc272ad9b28542905f
2021 F20101109_AABNEQ wilson_j_Page_12.txt
c7bd501c85c98aefcecac228c6008018
37cb03ca3638174ec74a88205b461985c05ca143
1051933 F20101109_AABNHM wilson_j_Page_30.jp2
959c4d1d8b756dcd8c4ad64b3303cf2c
96c8307d2f9f4977fd875f4a7bf840dfabf185f9
1847 F20101109_AABNKK wilson_j_Page_21.txt
9c4760497db0daf2c8242dd7083dd7f7
fe8f74cd3bb5c5888a2b55d4dd3823080af8a15a
26955 F20101109_AABNER wilson_j_Page_16.jpg
c15954b643dc25ec6b3539257c3a778e
0836bd54ee5865dc0ff4a7a6e669a5c96078a1da
F20101109_AABNHN wilson_j_Page_31.jp2
e6b65bae10f0a4f0d8c1bd4f226463c8
e5e95f8b6056fbaf977bc8aa48173bc563f35504
4164 F20101109_AABNES wilson_j_Page_29thm.jpg
5894790785c190debceb4d325fde2964
9cca227f6aeef5ac8d3c49fdfac7e7c1570100ab
788832 F20101109_AABNHO wilson_j_Page_32.jp2
440bfb301c00caa90c0ae9aa8a2ccb05
9a794d731af27219212f80d5eeac20079da62373
776275 F20101109_AABNET wilson_j_Page_08.jp2
29c5343baa6037468a00554fbfe31b93
34e0c400b67b27416559aed0f9a7f48919b3d7a4
F20101109_AABNHP wilson_j_Page_01.tif
e489da3ae145acfe3b855b52a03f9690
36f9919f9771a3eb9555f0071f16dd9a8c9d488e
251 F20101109_AABNKL wilson_j_Page_22.txt
4b059d2eb62ce354f4d489c00db745df
480ee0e9467039b89df51edbbe70929165ef31bb
5281 F20101109_AABNEU wilson_j_Page_08thm.jpg
1be788063411eb0ff2d2c7339aab115e
091622761ac3969d2b74f0f4858cfe8e869f48f6
F20101109_AABNHQ wilson_j_Page_02.tif
f3fdd7493153a013110fb3a4f28d6366
0cd5b48002f6d5b254b2c4a9612731c13125c044
517 F20101109_AABNKM wilson_j_Page_23.txt
c3d699115e9c271f0f47d128861eb2bc
0601b2b76e6a0e92692b623cf59cdafa3c2bdcfe
80547 F20101109_AABNEV wilson_j_Page_12.jpg
33558aee5a11de29d657098657534b5c
cda4b781ce28a147ecb2505a57d090188de2f78d
F20101109_AABNHR wilson_j_Page_03.tif
7db3ffd1baf3947754dac6a95f84c7fd
89a4d4ea408bdd65276be70028dc534321e57763
321 F20101109_AABNKN wilson_j_Page_25.txt
1eff9d0a5000cad6efc3958c48db092f
6276fb0a5382c3af826adf21a3242a59b8d865e7
3501 F20101109_AABNEW wilson_j_Page_23thm.jpg
c3f148474159fa6dccc13c48de213f24
18fb558c05d9bc26f926f65f588ed8fdcf484b70
F20101109_AABNHS wilson_j_Page_04.tif
99cc15a34c75ea2d378856790335e5ca
a75315eaa04d5c3920828eef5802c87ceb9a88fd
2067 F20101109_AABNKO wilson_j_Page_26.txt
0f471edc49e2f92da20eff09131d7cf0
20121838b78a51e56dda290fa275749e6841ef05
2050 F20101109_AABNEX wilson_j_Page_11.txt
64a0fea4d122934b2155a1d666815e4f
5e39aedd10a1ade5aaf6b21e2e9fbc822215bf06
F20101109_AABNHT wilson_j_Page_05.tif
13f674c3311821adae8479d497186f28
ff0428b4678745de17b9c068f5920eed1e455408
2207 F20101109_AABNKP wilson_j_Page_27.txt
0d7b023ece404c435756e88c63e6ff81
e865a01fd473d614e025c87c0880981d626317f7
29796 F20101109_AABNGA wilson_j_Page_19.jpg
2c047d606eefe482a222e3385952a5bb
9fb4c8773f4b17f8609705cb6329168079eab26c
22197 F20101109_AABNEY wilson_j_Page_21.QC.jpg
6fcf8b534a46ec91b76e2b0f30aaf1ea
d4668b12c9d9103885b7c4acad20820c070e946a
F20101109_AABNHU wilson_j_Page_06.tif
9da3f323627059dae53eebcd9e126be1
5883d63a298f383faeed668b987b949ad820f5db
2118 F20101109_AABNKQ wilson_j_Page_28.txt
f3fc86eb5efe062be6b832609f05b18c
04ac8cc17f3a5f8a8a13185d4b83f5fd58a27a73
80322 F20101109_AABNGB wilson_j_Page_20.jpg
2bda42d368d03afbb0ff0df65b268f72
d81889e32742c0ff1ba9429ff950edd57abe9e0a
41651 F20101109_AABNEZ wilson_j_Page_10.pro
f251fcefee9e566be23794cdfe2eeb01
5d36f688f0be30914aa91ffbb735e051b59a83f6
F20101109_AABNHV wilson_j_Page_07.tif
935d65c9a7464384f50696e7595ca974
056e90495e80847a863826af36df3be902d1eb5f
1024 F20101109_AABNKR wilson_j_Page_29.txt
9b33b0383f81df1d1997539cc71bf4ff
f1050680e0b2d146f403b157e869f41f95a4e85f
66741 F20101109_AABNGC wilson_j_Page_21.jpg
090cceb660b13a4fafe156ae765e3338
6fb22155e5ef06760b31b60d9bdf420e6a89dd3c
F20101109_AABNHW wilson_j_Page_08.tif
a0142defc17481ade525bf63fe33a9db
e61afddcd4bbc32081c86b284130e6324f2c8362
2302 F20101109_AABNKS wilson_j_Page_30.txt
e266bfe716890ab3671674762b573c04
7384f4a965eb35ff4809005afc377729f7ecfdd3
16936 F20101109_AABNGD wilson_j_Page_22.jpg
28a2202e29d0b6182b825450dfc948b6
c472b90238d25a1f5a120f713c5123b4324527d4
F20101109_AABNHX wilson_j_Page_09.tif
3c94a5628132e83860e95ae6794f2201
e89923d572d6114cc23a2b9ddd5ca3afc80e1e12
2162 F20101109_AABNKT wilson_j_Page_31.txt
5c33528e33e73837409c8c38ea30e533
fbf7e14fc432a64382d793219342ef098e76dca8
29192 F20101109_AABNGE wilson_j_Page_23.jpg
030fa8641bf34216296313c7e18f28ec
cc2ba5c278107ebe09ab456011059b7c5a43a8d6
33218 F20101109_AABNJA wilson_j_Page_08.pro
1e6f75b0795774d97a0819691636116b
017c20cb6fe1358b7b2f76d4c90154f0e4ef7473
F20101109_AABNHY wilson_j_Page_11.tif
592a2727e19b0cf0b8f0def1de27eaf9
ac20ae72d329d336088ad652b011b5a7930de43c
1405 F20101109_AABNKU wilson_j_Page_32.txt
ee81d47a715dfca928fe4171b7166e4c
b04116be60109986aa0d175fe0ee8a90b62c70d2
38930 F20101109_AABNGF wilson_j_Page_24.jpg
5ee5648e8509c6137bd77ba41544c826
24e48cbb8278f32620a40e8d52dfc8b9e48f8bb9
53247 F20101109_AABNJB wilson_j_Page_09.pro
d3a66129b60cb46bcdacef1d0dc9783c
2ac213c76c3d992b0c30d51b50da0739a23c5b4f
F20101109_AABNHZ wilson_j_Page_12.tif
291c5dba15c4677437f57cc13fbbb571
f9c34c5c003197e8e8094e1d27abf2ac3aa6d79a
2281 F20101109_AABNKV wilson_j_Page_01thm.jpg
ca3700988d873ed2b53b734c536c1f00
9fb77588be6249b53ae02c599c531b8b288ccf11
16759 F20101109_AABNGG wilson_j_Page_25.jpg
301cbc628db739d8a1c6ef426a883d1b
3ea6c1d0308444b077320e45db8b5e6364d47af1
49063 F20101109_AABNJC wilson_j_Page_11.pro
d48a14d6124bf53b32e94019fbddb2d4
fe98882bb3a0da8d9fa3ffc523bf80396102d68c
215829 F20101109_AABNKW wilson_j.pdf
b88455344bc54eebe88689c8a76c3c49
d3b5539af71da18171b56adec254a9334f20591f







THE NATURE AND PREVALENCE OF ALEXIA INT APHASIA


By

JONATHAN PAUL WILSON





















A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF ARTS

UNIVERSITY OF FLORIDA

2008































O 2008 Jonathan Paul Wilson































To my parents.









ACKNOWLEDGMENTS

I thank my supervisory committee for their mentoring, the staff and members at the UF

Libraries for their keen research assistance, and the participants in this research and their families

for their honest and open participation. I thank the Department of Veteran Affairs RR&D Brain

Rehabilitation and Research Center and Dr. Kendall's laboratory staff for their generous support.












TABLE OF CONTENTS


page

ACKNOWLEDGMENT S .............. ...............4.....


LI ST OF T ABLE S .........__.. ..... .___ ...............6....


LIST OF FIGURES .............. ...............7.....


AB S TRAC T ......_ ................. ............_........8


CHAPTER


1 INTRODUCTION ................. ...............9.......... ......


2 M ETHOD S ................. ...............11.......... .....


Participants ................. ...............11.......... .....
Item Stim uli ............... ...............12....
Real Word Stimuli ................. ...............12........... ....

Irregular Word Stimuli ............... ...............13....
Pseudohomophone Word Stimuli ............. ....._ ...............13...
Nonword Stimuli .............. ...............14....
Data Collection Procedure ................. ...............14........... ....
Scoring ................. ...............15.................


3 DATA ANALYSIS .............. ...............18....


Research Question One............... ...............18..
Research Question Two ................. ...............18........... ....
Scoring Reliability ................. ...............19.......... .....


4 RE SULT S ................. ...............20.......... .....


Research Question One............... ...............20..
Research Question Two ................. ...............20........... ....
Scoring Reliability ................. ...............21.......... .....


5 DI SCUS SSION ................. ...............26................


Research Question One: Prevalence and nature of alexia .............. ...............26....
Research Question Two: Predominant error type ................. ...............28...............


APPENDIX


LIST OF REFERENCES ................. ...............30........... ....


BIOGRAPHICAL SKETCH ................. ...............32.......... .....










LIST OF TABLES

Table page

2-1 Item stim uli .............. ...............17....

4-1 Statistical profile of normal subj ects ................. ...............22..............

4-2 Covariate effects in phonological/deep alexia ................ ...............24...............

4-3 Variable effects on reading accuracy ................. ......... ...............24. ...










LIST OF FIGURES


Figure page

4-1 Distribution of total scores among the normal group. ...........__......_ ...............23

4-2 Prevalence of alexia within aphasia. .............. ...............23....

4-3 Distribution by error type among the group of aphasics with alexia ................ ...............25









Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Arts

THE NATURE AND PREVALENCE OF ALEXIA INT APHASIA

By

Jonathan Paul Wilson

May 2008

Chair: Diane L. Kendall
Major: Communication Sciences and Disorders

The purpose of this study was to describe the prevalence and nature of alexia in individuals

with aphasia and to delineate types of errors produced by individuals with phonologic and deep

alexia. Forty-one individuals with aphasia and twenty-nine controls performed an oral reading

task of real word, pseudohomophone and nonword stimuli. Results showed that the prevalence

of alexia associated with aphasia was found to be 80.5% and the most predominate type of alexia

was phonological/deep. Predominate error type produced by alexics was phonologic (p= 0.0004)

lending support for the simultaneous activation hypothesis. Further, regarding stimuli type,

regular real words were read more accurately than irregular words which were in turn more

accurate than pseudohomophones and nonwords. Finally, we found a significant covariate effect

of years of formal education and reading accuracy both within and across all categories and

groups (p= 0.0085).









CHAPTER 1
INTTRODUCTION

Alexia is an acquired impairment to a premorbidly literate individual's ability to read as a

result of a lesion, typically within the left hemisphere perisylvian language zone of the brain. It

is commonly accepted that alexia presents concurrently with aphasia, however the incidence and

prevalence of alexia within and across aphasia syndromes has not been described and reports of

aphasic oral reading performance is typically limited to individual case series (Coslett, 2000;

Cherney, 2004).

Alexia syndromes are typically classified according to psycholinguistic principles in terms

of the pattern of reading errors revealed during oral reading of real words, pseudohomophones

and nonwords and have been described using either a dual route cascade or parallel distributed

processing models (Plaut et al., 1996; Coslett, 2000; Cherney, 2004). While there are inherent

differences between these two models in terms of processing components, only the basic

assumptions describing the alexia syndromes are reviewed here.

Surface alexia reflects impairments at the level of the lexical/semantic system and relative

isolation of the phonological system. Individuals with surface alexia read real and nonwords

using orthography to phonology with no or limited contribution from semantics resulting in the

ability to read nonwords and difficulty reading irregular words. Phonological alexia, on the other

hand, reflects impairments at the level of the phonological system and relative isolation of the

lexical/semantic system. Individuals with phonological alexia read real and nonwords using an

orthographic to semantics route with limited contribution from phonology resulting in the ability

to read real words in the face of impaired ability to read unfamiliar words and nonwords. The

mechanisms for deep alexia are similar to phonologic alexia in terms of impairment at the level

of the phonological system and secondary impairment to the isolated semantic system. It has









been hypothesized that phonological and deep alexia actually represent points along a continium

based on observations that deep alexia often resolves towards phonologic alexia and based on

symptom succession (Friedman, 1996; Glosser et al., 1990; Crisp et al., 2006). Individuals with

deep alexia read words using orthography to impaired semantics with no contribution from

phonology and are rendered unable to read nonwords and unfamiliar words (Plaut et al., 1996;

Glosser et al., 1990; Crisp et al., 2006).

The purpose of this study was to describe the prevalence and nature of alexia in individuals

with aphasia and to delineate types of errors produced by individuals with central alexia. Error

analysis can provide a window into the mechanisms underlying alexic syndromes. It is

hypothesized that individuals with deep or phonological alexia will produce a greater number of

real word substitution errors that are not semantically related to the target item than individuals

with surface alexia because they rely on an orthographic to semantics route to read with limited

contribution from phonology.

Further descriptive questions will be considered; in particular we plan to describe the

difference between reading performance of normal readers and individuals with aphasia both

within and across word types. It is hypothesized that individuals with aphasia will be more

globally impaired during the oral reading task than normal controls and that distinct patterns of

aphasic reading performance both within and across word types will emerge consistent with the

literature.









CHAPTER 2
METHOD S

Participants

Participants were recruited through the VA RR&D Brain Rehabilitation and Research

Center and surrounding community in Gainesville, Florida and consented under IRB #306-2006.

Participants with aphasia (n=41) and normal control participants (n=29) were matched on the

basis of age, gender, and education level. All participants were right handed, monolingual

English speakers aged 21-80 years old.

Inclusion criteria for the aphasia group was a history of single left hemisphere stroke

(documented by CT or MRI imaging data) at least 6 months prior to enrollment in this proj ect

resulting in aphasia as determined by standardized testing (Western Aphasia Battery). Exclusion

criteria for both groups was pre-existing neurological disease or severe impairment in vision or

hearing. Each participant was described using several standardized measures to assess their

neurological status, word finding problems, reading competence, speech motor performance, and

to screen for visual/auditory acuity. The aphasic group was a convenience sample and included

7 Broca's aphasics, 27 Anomic aphasics, 4 Conduction aphasics, 2 Transcortical Motor aphasics,

and 1 Global aphasic.

Aphasic participants were profiled using the Western Aphasia Battery (WAB) (Kertesz,

1982) the Boston Naming Test (BNT)(Kaplan et al., 1983) the Reading Comprehension

Battery for Aphasia (RCBA)(Lapointe et al., 1979), and a non-standardized speech motor

performance test which was used to identify the presence or absence of apraxia of speech or

dysarthria (Duffy, 2005). During the speech motor performance test participants were asked to

repeat back to the investigator five increasingly longer sentences which were verbally presented

to each participant one at a time. The same five sentences were then presented again verbally









and the participant was instructed to repeat the sentences back to the investigator but this time

"twice as fast". Participant responses were digitally recorded using a Marantz PMD671

Professional Compact Flash Recorder and Audiotechnica ATM 76 microphone. Participant

responses were subj ectively scored offline by the investigator to identify apraxic or dysarthric

verbal errors according to the symptomology of these disorders presented within the literature.

All participants completed a vision screening in which a series of symbols were presented at the

top of a computer screen and were asked to identify the corresponding symbols at the bottom of

the screen within a row of similar symbols by pointing. The symbols were presented in bold

lowercase Arial font at 72 point centered on a white background.

The normal control participants were assessed using the same standardized measures as the

aphasia group with the exception of the WAB and the RCBA and were also given the Mini-

Mental Status Examination (Folstein et al., 1975) and the National Adult Reading Test (NART)

(Nelson, 1982).

Item Stimuli

Stimuli were developed for this proj ect consisting of 39 nouns (24 with regular spelling

patterns, and 15 with irregular spelling patterns), 30 nonwords and 12 pseudohomophones. Item

stimuli are shown in Table 2-1. Four categories were selected consisting of real words, irregular

words, pseudohomophones, and nonwords. Different selection criteria were used for the

selection of words for each category based on data obtained from the MRC Psycholinguistic

Database (Wilson, 1988).

Real Word Stimuli

The selection criteria for hierarchy of the real words was controlled according to word type

and only nouns were selected. Word length was broken down into two levels, number of

syllables, and number of graphemes and phonemes which was controlled within each syllable.









For example one syllable words would have 3-4 graphemes/phonemes, two syllable words would

have 4-6 graphemes/phonemes, three syllable words would have 7-9 graphemes/phonemes, four

syllable words would have 9 graphemes/phonemes and a five syllable words would have 10

graphemes/phonemes. The Thorndike-Lorge written frequency was equated within and across

all categories and all average values were within 1 standard deviation. The admissibility of

clusters and blends was determined by word length with inclusion not permitted for short words

and permitted for long words. All words were also described for the age of acquisition rating,

concreteness rating, familiarity rating, imagability rating, and the number of digraphs.

Irregular Word Stimuli

Irregular words were defined as "words that violate typical letter-sound patterns in

English" (Spear-Swerling et al., 2004). The selection criteria for hierarchy of the irregular words

was controlled according to syllable length and all words were 1-3 syllables in length because

prior test batteries typically go to 3 syllables. Selection criteria also included the Thorndike-

Lorge written frequency and all words were divided into a high or low frequency subcategories

with a high frequency range of 1-100 and a low frequency range of 800-2000. All words were

also described for the age of acquisition rating, concreteness rating, familiarity rating,

imagability rating, and the number of digraphs.

Pseudohomophone Word Stimuli

The primary criterion for the selection of the pseudohomophones was based on the

Thorndike-Lorge written frequency. For this category, a 1 syllable real word was self converted

into a pseudohomophone to determine the written word frequency. All words were divided into

a high or low frequency subcategory with a high frequency range of 1-100 and a low frequency

range of 800-2000. The pseudohomophones were also described for the age of acquisition

rating, concreteness rating, familiarity rating, imagability rating, and the number of digraphs.









Nonword Stimuli

Nonwords were created and controlled according to the following hierarchy: consonant

and vowel frequency and frequency values from Shriberg and Kent (1982) were used in the

criteria selection. The frequency of the consonants and vowels were divided into high and low

frequency subcategories. For the vowels the high frequency range was greater than 7.0, the low

frequency range was less than 4.0 and for the consonants the high frequency range was greater

than 5.0 and the low frequency range was less than 2.0. Thus, all words in the high frequency

category contained only high frequency consonants and vowels. Similarly, all words in the low

frequency category contained only low frequency consonants and vowels. One syllable, two

syllable, and three syllable nonwords were created using the repertoire of consonants and

vowels.

Each syllable length category was also divided into low and high frequency words. All

nonwords had CV word initial. The sum and average of biphone probability using the Phonetic

Probability Calculator (Vitevitch & Luce, 2004) was used calculate the sum of all biphone

probabilities within each nonword. The average of the biphone probability for each category

(e.g. 1-syllable, high frequency words) was also calculated. The number graphemes and

phonemes was controlled within each syllable with one syllable nonwords having 3-4

graphemes/phonemes, two syllable nonwords having 4-6 graphemes/phonemes and three syllable

nonwords having 7-13 graphemes/phonemes

Data Collection Procedure

Stimuli within each stimulus category were randomized for presentation by computer

software and were presented to the participants one at a time using a Dell Lattitude X1 Laptop.

Participants were then asked to read each stimuli aloud. Stimuli were presented centered in the

middle of a white screen in black, bolded, lowercase Arial font set at 72 points. The order of










presentation of stimulus categories were also randomized within and across stimulus categories.

Stimulus items were advanced automatically by the computer software using an inter-stimulus

interval set at 8.0 seconds. Each stimulus item was advance to the next stimulus item without a

transition interval.

Scoring

The inter-stimulus interval was used to ensure that test conditions were uniform across

participants and participant' s responses to a stimulus item beyond 8.0 seconds were scored as

incorrect. Only data on correct responses were analyzed. Responses to stimuli were recorded

digitally and scored offline for accuracy and error type using a Marantz PMD671 Professional

Compact Flash Recorder and Audiotechnica ATM 76 microphone. A response was scored as

correct if it matched the target stimulus and did not contain an omission, addition, transposition

or substitution error. Close approximations and distortions due to apraxia of speech, dysarthria

or phonetic differences were scored as correct since they are considered by this design to involve

motor speech planning, programming or execution level errors or differences and not linguistic

planning or programming level errors. Incorrect responses were defined as false starts, no

response and presence of semantic and / or phonologic errors. Errors were scored as either a

"phonological" error, a "verbal" error or an "other" error.

For the purposes of this design a phonological error were operationally defined as a

phonologic substitution error (e.g. one phoneme subsitition), a phonologic addition error (e.g.

one phoneme), a phonologic omission error (e.g. One phomeme), a transposition or exchange

error, a devoicing error or a voicing, a neologistic error which was defined as a nonword

involving multiple phonologic errors. A "verbal" error was operationally defined as a real word

substitution error that was not semantically related to the target stimulus item, a regularization

error, a pure semantic error (a real word substitution which was semantically related to the target










stimulus), and a derivational error (the addition or omission of morphologic endings). An

"other" error was operationally defined as a circumlocution (e.g. "the thing you open" / door), a

compensatory error without correctly producing the word (e.g. c a t......), no vocalization, an

apraxic error (e.g. /ah, ah, ah/), a false start (e.g. "d, d, d, dar, dart"), a compensatory error (E.g.

"c a t" spells cat), a distortion (e.g. consontant and vowel imprecision, or prolongation) or a

stress error (e.g. "A_11y vs allY).










Table 2-1. Item stimuli
Real Words Irregular Words
lot chance
job laugh
red suit
bin pew
fib coup
itch heir
body office
baby promise
city service
melon ally
vigil nausea
boxer bodice
afternoon ratio
president tentative
family rhapsody
caramel
promoter
meteorite
ultimatum
diplomacy
regulator
di ability
imb ecility
generosity


Pseudohomophones
fyte
rhed
phine
traine
kupp
pset
phinn
clinck
jirm
rhigg
troall
kaud


Nonwords
nis
reat
kes
nush
than
yane
dessy
simite
leedle
junooge
choithane
shounooth
tisadel
sedeatin
nysimin
shoinaej outh
chaythoinooth
jounaethawn









CHAPTER 3
DATA ANALYSIS

Research Question One

To answer research question one and to determine the prevalence and type of alexia within

the aphasic group simple descriptive statistics including means, standard deviations, and

percentages for variables within normal, aphasic, and phonological/deep alexia subj ects were

used. The normal control group's mean and standard deviation was calculated for overall

accuracy across word types. Any participant within the aphasia group whose overall accuracy

score fell below two standard deviations of the normal control group's mean was profied by this

analysis as having alexia. For each participant, accuracy across each word type was calculated.

Each participant within the aphasia group identified with alexia was further profied as having

either surface, phonological or deep alexia based on the following criteria: If the participant' s

nonword accuracy exceeded their regular word accuracy they were classified as having surface

alexia. If the participant' s regular word accuracy exceeds their nonword accuracy or was equal to

their nonword accuracy they were classified as having phonological/deep alexia.

Research Question Two

To compare the amount of verbal errors and the amount of phonological errors among

subj ects with phonological/deep alexia, one-way repeated measures ANCOVA was used with the

error type as the factor while controlling for age, gender, education, months post onset, and

history of speech therapy using the Mixed procedure in SAS.

To determine if there was a difference in reading performance and moreover if there was a

difference in reading performance across word types between normal subjects and aphasic

subjects, a multivariate linear regression was used to account for the correlation due to

simultaneous measurements on several dependent variables on a same subject. The dependent









variables, total score, regular word, irregular word, pseudohomophone, and nonword sub total

scores, were simultaneously related with the factor group (normal or aphasic) while controlling

for covariates age, gender, education, and history of speech therapy in one model using the GLM

procedure in SAS.

Scoring Reliability

To examine the intra-rater scoring reliability and inter-rater scoring reliability, Kappa

coefficients were calculated to describe the agreement in identifying correct responses to items

and classifying error responses to items between two ratings by the same rater and the agreement

between two different raters, respectively.









CHAPTER 4
RESULTS

Research Question One

Most individuals (33 out of 41) with aphasia (80.49%) fell below 2 standard deviations of

the normal reading group total mean (56.93, s.d. 6.16) and were classified as presenting with

alexia. Descriptive statistics for variables among normal subjects are shown in Table 4-1 and

normal total score distribution is shown in Figure 4-1. A number of individuals (8 out of 41)

with aphasia (19.5 1%) fell within 2 standard deviations of the normal reading group mean and

were classified as not presenting with alexia. Prevalence of alexia within aphasia is shown in

Figure 4-2. Of those individuals with alexia and aphasia, all (33 out of 33 or 100%) were

determined to read regular words more accurately than nonwords and were subsequently

classified as presenting with alexia of the phonological/deep type and no individual with alexia

and aphasia (0 out of 33 or 0%) presented with an alexia of the surface type.

Research Question Two

The results of comparing the amount of verbal errors and the amount of phonological

errors among subj ects with phonological/deep alexia are shown in Table 4-2. Subj ects with

Phonological/Deep Alexia made significantly more phonological errors (p= 0.0004) than verbal

errors after controlling for age, gender, months post onset, education, history of speech language

therapy. Distribution of alexic reading error types are shown in Figure 4-3.

There is a significant difference in total score between the normal reading group and the

subjects with aphasia after controlling for gender, age, education and history of speech therapy.

The effect of variables on reading performance are shown in Table 4-3. The subjects with

aphasia had significant lower mean total score (26. 117 less) than the normal reading group after

controlling for covariates. Education is also significantly positively associated with total scores









(p= 0.005). MANOVA tests show that there is significant overall group (aphasic versus normal)

effect (p < 0.0001) and overall education effect (p= 0.0085) on total scores.

There is a significant difference in Regular word, Irregular word, Pseudohomophone, and

Nonword subtotal scores between the normal reading group and the subj ects with aphasia after

controlling for gender, age, education, and history of speech therapy. The subj ects with aphasia

had significant lower Regular word (7.765 less), Irregular word (6.787 less), Pseudohomophone

(5.285 less), and Nonword (6.280 less) subtotal scores than the normal reading group after

controlling for covariates. Education is also significantly positively associated with Regular

word (p= 0.015), Irregular word (p= 0.019), and Nonword (p= 0.0003) subtotal scores, and

marginally significantly associated with Pseudohomophone (p= 0.059) subtotal scores.

MANOVA tests show that there is significant overall group (aphasic versus normal) effect (p <

0.0001) and overall education effect (p= 0.0085) on all subtotal scores.

Scoring Reliability

Kappa coefficient (95% confidence interval) is 0.9764 (0.9702, 0.9825) and 0.9603

(0.9531, 0.9674) for the agreement between ratings by the same rater at different time on

identifying correct responses to items and on classifying error responses to items, respectively,

and is 0.9024 (0.8779, 0.9269) and 0.8462 (0.8197, 0.8727) for the agreement between ratings by

different raters on identifying correct responses to items and on classifying error responses to

items, respectively. These high kappa coefficients indicate strong agreement between ratings by

the same rater at different time and between ratings by different raters.










Table 4-1. Statistical profile
Variable N
Age 29
Education 29
Female 29
SLP-history (yes) 29
Total score 29


of normal subj ects
Mean & SD
61.66 & 9.72
15.45 & 2.58


% yes


62.07
6.90


56.93 & 6.16






















+Normal ~Controls


0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69

Total Reading Score (out of 69)

Figure 4-1. Distribution of total scores among the normal group










SAphasia andn Ale ia

Aphasia only


Figure 4-2. Prevalence of alexia within aphasia










Table 4-2. Covariate effects in phonological/deep alexia
Variable Coefficient & SE P-value


Intercept
Error Type (phonological)
Gender (female)
Age
Education
SLP history (no)
Months post onset


-1.940 + 9.704
15.000 & 3.790
-3.883 & 3.003
0.238 & 0.155
-0.188 & 0.481
-0.272 & 3.323
-0.011 & 0.022


0.843
0.0004
0.207
0.137
0.699
0.935
0.612


Table 4-3. Variable effects on reading accuracy
Variable Coefficient & SE P-value
Intercept 17.709 & 13.669 0.200
Group* (ref: normal) Aphasic -26. 117 & 4.663 <.0001
Gender (ref: male) Female 2.265 & 3.584 0.530
Age 0.151 & 0.182 0.408
Education* 1.728 & 0.596 0.005
SLP history (ref: yes) no 1.916 & 4.260 0.655
* MANOVA tests show significant overall group effect (P-value < 0.0001) and education effect
(P-value = 0.0085) on total and all subtotal scores.














60


50-




40-




S30




20




10






Phonological Verbal
Reading Error Type


Figure 4-3. Distribution by error type among the group of aphasics with alexia


Other









CHAPTER 5
DISCUS SION

The purpose of this study was to describe the nature and prevalence of alexia in aphasia.

Our finding that alexia is common both within and across aphasic syndromes is supported by the

literature (Webb et al., 1983). We found that the reading performance of individuals with

aphasia is typically impaired, and that the severity but not the nature of this impairment is highly

variable and associated with an individual's educational experience. This finding is novel and

will be discussed in further detail below. We found that phonological/deep alexia is the only

central alexia associated with the aphasia group and that the predominant reading error is

phonological in nature.

Research Question One: Prevalence and nature of alexia

While a significant maj ority of individuals with aphasia had alexia we note that a number

of individual's with aphasia scored well within two standard deviations of the normal range.

While it is generally accepted that alexia can present either as an isolated symptom or within the

context of an aphasic syndrome we conclude on the basis of this study that no dependent

relationship exists. We find that aphasia can present without significant impairment to the

reading modality. In contrast a number of early group studies found that alexia always occurs

within aphasia (Webb et al., 1983; Duffy et al., 1976), but this finding is controversial

(Hoffmann et al., 1997; Nance et al., 1981). We speculate that the close association of alexia

both within across aphasic syndromes and the finding that severity of aphasia is not significantly

correlated with severity of alexia is suggestive either of a highly vulnerable or of a distributed

cortical network for reading. This account is well supported by recent radiographic and

neuroimaging studies of normal readers elsewhere (Church et al., 2008; Mechelli et al., 2005).









The Einding that both the aphasic and normal groups read real words better than nonwords

and that the aphasic group was generally impaired suggests a graceful degradation of the reading

system. This aphasic pattern of reading performance together with reading error analysis is

consistent with earlier descriptions of phonological and deep alexia and is inconsistent with

descriptions of surface alexia (Cherney, 2004; Plaut et al., 1996). We account for this finding on

the basis of the right hemisphere hypothesis (Coltheart, 2000; Hildebrandt, 1994). Phonological

alexia is prevalent because the right hemisphere usually lacks the substrate of phonological

sequence knowledge that could compensate for the results of the left hemisphere lesion, whereas

it is better equipped to support whole word reading to some degree and thereby compensate

surface alexia (Coltheart, 2000; Hildebrandt, 1994).

We account for our Einding that years of formal education is inversely associated with

severity of alexia on the basis that literate adults with greater educational experience may rely

more on whole word reading routes than literate adults with less educational experience. This

account is supported by a number of aphasia group studies which found that severity of aphasia

is inversely associated with years of formal education (Smith, 1971; Conor, 2000). Recent

neuroimaging studies of children and adults have also shown that literate adults rely less on

phonological and auditory processes to read than children (Church et al., 2008; Bitan et al.,

2007). We speculate that decreased activation of phonological and auditory pathways during

reading is due to increased reliance on whole word reading routes supported by semantics. It

follows that adults with greater educational experience may have richer semantic support

systems used for reading and will therefore be better protected from the effects of a neurological

insult that interferes with phonological route processing. The Einding that individuals with

greater levels of educational experience make less reading errors under stimulus conditions that









preclude whole word reading (nonwords) suggests that whole word readers also have fully

mature phonological sequence knowledge. The use of whole word reading routes may be

entirely conditional on underlying phonological efficiency (Church et al., 2008; Bitan et al.,

2007). It may be that degraded phonological efficiency also implicates a degraded semantic

system leading to phonologically based reading errors and at it' s furthest extreme semantically

based reading errors (Southwood et al., 2000). This point will be discussed in further detail

below.

Research Question Two: Predominant Error Type

Our finding that individuals with phonological and deep alexia predominantly made

phonological errors and not whole word substitutions is unexpected. Earlier descriptions of

phonological/deep alexia describe word substitutions as the defining characteristic of this form of

alexia (Southwood et al., 2000; Cherney, 2004; Coslett, 2000). Phonological and deep alexics

have impaired phonological systems and only relatively spared semantic systems. The finding

that phonological errors are more prevalent during oral reading is in line with the simultaneous

activation hypothesis which hypothesizes that simultaneous activation of competing impaired

primary reading routes will overide the lexical/semantic reading route sufficiently to activate a

visually based or neologistic phonological error (Southwood et al., 2000). According to this

hypothesis stimulus conditions which prohibit whole word reading (nonwords and unfamiliar

word stimuli) will increase the probability of phonological errors and semantic errors will only

occur with severe damage to direct and indirect reading routes. At the furthest extreme nonword

reading will be entirely abolished. This is the case in deep alexia (Southwood et al., 2000). It

may also be that phonological errors are more prevalent than whole word substitutions because

the right hemisphere usually lacks the substrate of phonological sequence knowledge that could









compensate for the results of the left hemisphere lesion, whereas it is better equipped to support

whole word reading to some degree (Coltheart, 2000; Hildebrandt, 1994).

Implication of Findings

These findings can inform clinical practice in several ways. Since the majority of aphasics

have alexia, it is suggested that initial testing in the clinical environment should incorporate a

reading evaluation in addition to traditional aphasia tests. While oral reading and reading for

comprehension share neural mechanisms, at present, there is insufficient clinical data to support

any conclusion that a significantly positive correlation exists within this population. Since all

individuals with alexia have phonologic alexia, treatment should be directed at the level of the

phonologic processor. There is evidence in aphasic literature that by treating the phonologic

system, reading as well as speech production improves (Kendall et al., 2003; Kendall et al.,

2006).










LIST OF REFERENCES


Bitan, T., Cheon, J., Lu, D., Burman, D.D., Gitelman, D.R., Mesulam, M.M., Booth, J.R. (2007).
Developmental changes in activation and effective connectivity in phonological processing.
Neuroimage. 38(3), 564-75.

Cherney, L.R. (2004). Aphasia, alexia, and oral reading. Topics in Stroke Rehabilitation. 11(1,
22-36.

Church, J.A., Coalson, R.S., Lugar, H.M., Petersen, S.E., Schlaggar, B.L. (2008). A
Developmental fMLRI Study of Reading and Repetition Reveals Changes in Phonological and
Visual Mechanisms Over Age. Cerebral Cortex. Advance Access Publication JanJJJJJJJJ~~~~~~~~~ 31, 1-12.

Coltheart, M. (2000). Deep dyslexia is right-hemisphere reading. Brain and Language. 71(2),
299-309.

Coslett, H.B. (2000). Acquired dyslexia. Seminars in Neurology. 20(4), 419-26.

Crisp, J., Lambon Ralph, M.A. (2006). Unlocking the nature of the phonological-deep dyslexia
continuum: the keys to reading aloud are in phonology and semantics. Journal of Cognitive
Neuroscience. 18(3), 348-62.

Duffy, R.J. (2005). Motor Speech Disorders: substrates, differential diagnosis, and management
(2nd ed.). St. Louis, MO: Elsevier Mosby.

Duffy, R.J., Ulrich, S.R.(1976). A comparison of impairments in verbal comprehension, speech,
reading, and writing in adult aphasics. Journal of Speech and Hearing Disorders. 41(1, 1 10-9.

Folstein, M.F., Folstein, S.E., McHugh, P.R. (1975). Mini-mental state. A practical method for
grading the cognitive state of patients for the clinician. Journal of Psychiatric Research. 12 (3),
189-98.

Friedman, R.B. (1996). Recovery from deep alexia to phonological alexia: points on a
continuum. Brain and Language. 52(1, 114-28.

Glosser, G., Friedman, R.B. (1990). The continuum of deep/phonological alexia. Cortex. 26(3),
343-59.

Hildebrandt, N. (1994) The Reicher-Wheeler effect and models of deep and phonological
dyslexia. Journal ofNeurolinguistics. 8(1, 1-18.

Hoffmann, M., Sacco, R., Mohr, J.P., Tatemichi, T.K. (1997). Higher cortical function deficits
among acute stroke patients: The stroke data bank experience. Journal of Stroke and
Cerebrovascular Disease. 6(3), 114-20.

Kaplan, E., Goodglass, H., Weintraub, S. (1983). The Boston Naming Test. Philadelphia, PA:
Lea & Febiger.











Kendall, D., Conway, T., Rosenbek, J., Gonzalez-Rothi, L. (2003). Phonological rehabilitation
of acquired phonologic alexia. Aphasiology. 1 7(11), 1073-1095.

Kendall, D., Rodriguez, A., Rosenbek, J., Conway, T., Gonzalez-Rothi, L. (2006). The Influence
of Intensive Phono-Motor Rehabilitation of Apraxia of Speech. Journal ofRehabilitation
Research and Development. 43(3), 323-336.

Kertesz, A. (1982). The Western Aphasia Battely. Austin, TX: PRO-ED Inc.

LaPointe, L.L., Horner, J. (1979). Reading Comprehension Battery for Aphasia. Austin (TX):
PRO-ED Inc.

Mechelli, A., Crinion, J.T., Long, S., Friston, K.J., Lambon Ralph, M.A., Patterson, K.,
McClelland, J.L., Price, C.J. (2005). Dissociating reading processes on the basis of neuronal
interactions. Journal of Cognitive Neuroscience. 17(11), 1753-65.

Nance, A.L., Ochsner, G.J. (1981). Language modality performance patterns in aphasia.
Journal of Conanunication Disorders. 14(5), 421-8.

Nelson, H.E. (1982). NationalAdultRea~ding Test. Windsor, UK: NFER-Nelson.

Plaut, D.C., McClelland, J.L., Seidenberg, M.S., Patterson, K. (1996). Understanding normal
and impaired word reading: computational principles in quasi-regular domains. Psychological
Review. 103(1), 56-115.

Southwood, M.H., Chatterjee, A. (2000). The interaction of multiple routes in oral reading:
evidence from dissociations in naming and oral reading in phonological dyslexia. Brain and
Language. 72(1), 14-39.

Spear-Swerling, L., Brucker, P.O. (2004). Preparing novice teachers to develop basic reading
and spelling skills in children. Annals ofDyslexia. 54(2), 332-64.

Vitevitch, M. S., Luce, P.A. (2004). A web-based interface to calculate phonotactic probability
for words and nonwords in English. Behavior Research M~ethods, hIstruntents, and Computers.
36, 481-487.

Webb, W.G., Love, R.J. (1983). Reading problems in chronic aphasia. Journal of Speech and
Hearing Disorders. 48(2), 164-71.

Wilson, M.D. (1988). The MRC Psycholinguistic Database: Machine Readable Dictionary,
Version 2. Behavioural Research M~ethods, Instruments and Computers. 20(1), 6-1 1.









BIOGRAPHICAL SKETCH

Jonathan Paul Wilson was born in 1971, in Bangor, Northern Ireland. He is the eldest son

of two children and grew up in Bangor, a seaside town on the east coast of Ireland. He attended

primary school in Bangor and graduated from his grammar school, the Royal Belfast Academical

Institution, in Belfast in 1989. He graduated from the Queen's University of Belfast in 1992

with an honors degree in English language and literature. He went on to study computing and

information systems at the University of Ulster where he received his post graduate diploma in

computing and information systems in 1998.

Upon graduating he joined the Royal Bank of Scotland (UK) where he worked as a

computer systems engineer and later as an account executive. In 2005 he relocated to Florida,

USA where he j oined the University of Florida' s masters program in the Department of

Communication Sciences and Disorders, majoring in speech-language pathology. Upon

completion of the master' s program Jonathan intends to pursue clinical certification as a speech-

language pathologist and will continue his clinical research into the PhD program at the

University of Florida starting in Fall 2008. His current research interests include adult

neurogenic communication disorders and the study of anemia.





PAGE 1

THE NATURE AND PREVALENCE OF ALEXIA IN APHASIA By JONATHAN PAUL WILSON A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS UNIVERSITY OF FLORIDA 2008 1

PAGE 2

2008 Jonathan Paul Wilson 2

PAGE 3

To my parents. 3

PAGE 4

ACKNOWLEDGMENTS I thank my supervisory committee for their me ntoring, the staff and members at the UF Libraries for their keen research assistance, and the participants in this research and their families for their honest and open participation. I thank the Department of Veteran Affairs RR&D Brain Rehabilitation and Research Center and Dr. Kendalls laboratory st aff for their generous support. 4

PAGE 5

TABLE OF CONTENTS page ACKNOWLEDGMENTS ............................................................................................................... 4LIST OF TABLES ...........................................................................................................................6LIST OF FIGURES .........................................................................................................................7ABSTRACT ...................................................................................................................... ...............8 CHAPTER 1 INTRODUCTION ................................................................................................................ ....92 METHODS ..................................................................................................................... ........11Participants .................................................................................................................. ...........11Item Stimuli .................................................................................................................. ..........12Real Word Stimuli ...........................................................................................................12Irregular Word Stimuli ....................................................................................................13Pseudohomophone Word Stimuli ....................................................................................13Nonword Stimuli .............................................................................................................14Data Collection Procedure ......................................................................................................14Scoring ....................................................................................................................... .............153 DATA ANALYSIS ............................................................................................................... .18Research Question One ...........................................................................................................18Research Question Two ..........................................................................................................18Scoring Reliability ..................................................................................................................194 RESULTS ..................................................................................................................... ..........20Research Question One ...........................................................................................................20Research Question Two ..........................................................................................................20Scoring Reliability ..................................................................................................................215 DISCUSSION .................................................................................................................. .......26Research Question One: Prevalence and nature of alexia ......................................................26Research Question Two: Predominant error type ...................................................................28 APPENDIX LIST OF REFERENCES ...............................................................................................................30BIOGRAPHICAL SKETCH .........................................................................................................32 5

PAGE 6

LIST OF TABLES Table page 2-1 Item stimuli ............................................................................................................. ...........17 4-1 Statistical profile of normal subjects ..................................................................................22 4-2 Covariate effects in phonological/deep alexia ...................................................................24 4-3 Variable effects on reading accuracy .................................................................................24 6

PAGE 7

LIST OF FIGURES Figure page 4-1 Distribution of total scores among the normal group. .......................................................23 4-2 Prevalence of alexia within aphasia. ..................................................................................23 4-3 Distribution by error type among th e group of aphasics with alexia. ................................25 7

PAGE 8

8 Abstract of Thesis Presen ted to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Arts THE NATURE AND PREVALENCE OF ALEXIA IN APHASIA By Jonathan Paul Wilson May 2008 Chair: Diane L. Kendall Major: Communication Sc iences and Disorders The purpose of this study was to describe the pr evalence and nature of alexia in individuals with aphasia and to delineate types of errors produced by individuals with phonologic and deep alexia. Forty-one individuals with aphasia and twenty-nine controls performed an oral reading task of real word, pseudohomophon e and nonword stimuli. Results showed that the prevalence of alexia associated with aphasia was found to be 80.5% and the most predominate type of alexia was phonological/deep. Predominate error type produced by alexics was phonologic (p= 0.0004) lending support for the simultane ous activation hypothesis. Furt her, regarding stimuli type, regular real words were read mo re accurately than irregular words which were in turn more accurate than pseudohomophones and nonwords. Finally we found a significant covariate effect of years of formal education and reading accura cy both within and across all categories and groups (p= 0.0085).

PAGE 9

CHAPTER 1 INTRODUCTION Alexia is an acquired impairment to a premorbidly literate indi viduals ability to read as a result of a lesion, typically within the left hemis phere perisylvian language zone of the brain. It is commonly accepted that alexia presents concurre ntly with aphasia, however the incidence and prevalence of alexia within and across aphasia syndromes has not been de scribed and reports of aphasic oral reading performance is typically limited to individual cas e series (Coslett, 2000; Cherney, 2004). Alexia syndromes are typically classified accord ing to psycholinguistic principles in terms of the pattern of reading erro rs revealed during oral readi ng of real words, pseudohomophones and nonwords and have been described using eith er a dual route cascade or parallel distributed processing models (Plaut et al ., 1996; Coslett, 2000; Cherney, 2004). While there are inherent differences between these two models in te rms of processing components, only the basic assumptions describing the alexia syndromes are reviewed here. Surface alexia reflects impairments at the leve l of the lexical/semantic system and relative isolation of the phonological syst em. Individuals with surface alexia read real and nonwords using orthography to phonology with no or limited contribution from semantics resulting in the ability to read nonwords and difficulty reading i rregular words. Phonological alexia, on the other hand, reflects impairments at the level of the phon ological system and relative isolation of the lexical/semantic system. Individuals with phonological alexia read real and nonwords using an orthographic to semantics route with limited c ontribution from phonology resu lting in the ability to read real words in the face of impaired ability to read unfamiliar words and nonwords. The mechanisms for deep alexia are similar to phonologi c alexia in terms of impairment at the level of the phonological system and secondary impairment to the isolated semantic system. It has 9

PAGE 10

10 been hypothesized that phonological and deep alexia actually repr esent points along a continium based on observations that deep alexia ofte n resolves towards phonologic alexia and based on symptom succession (Friedman, 1996; Glosser et al., 1990; Crisp et al., 2006). Individuals with deep alexia read words using orthography to impaired semantics with no contribution from phonology and are rendered unable to read nonwords and unfamiliar words (Plaut et al., 1996; Glosser et al., 1990; Crisp et al., 2006). The purpose of this study was to describe the pr evalence and nature of alexia in individuals with aphasia and to delineate types of errors pr oduced by individuals with central alexia. Error analysis can provide a window into the mechanisms underlying alexic syndromes. It is hypothesized that individuals with deep or phonological alexia will produce a greater number of real word substitution errors that are not semantica lly related to the target item than individuals with surface alexia because they rely on an orth ographic to semantics route to read with limited contribution from phonology. Further descriptive questions will be considered ; in particular we plan to describe the difference between reading performance of norma l readers and individu als with aphasia both within and across word types. It is hypothesized that individuals with aphasia will be more globally impaired during the oral re ading task than normal controls and that distinct patterns of aphasic reading performance both within and acro ss word types will emerge consistent with the literature.

PAGE 11

CHAPTER 2 METHODS Participants Participants were recruited through the VA RR&D Brain Rehabilitation and Research Center and surrounding community in Gainesvi lle, Florida and consented under IRB #306-2006. Participants with aphasia (n= 41) and normal control participan ts (n=29) were matched on the basis of age, gender, and education level. All participants were right handed, monolingual English speakers aged 21-80 years old. Inclusion criteria for the apha sia group was a history of si ngle left hemisphere stroke (documented by CT or MRI imaging data) at least 6 months prior to enrollment in this project resulting in aphasia as determin ed by standardized testing (Weste rn Aphasia Battery). Exclusion criteria for both groups was preexisting neurological disease or severe impairment in vision or hearing. Each participant was described using several standardized measures to assess their neurological status, word finding problems, read ing competence, speech motor performance, and to screen for visual/auditory acuity. The a phasic group was a convenien ce sample and included 7 Brocas aphasics, 27 Anomic aphasics, 4 Conduc tion aphasics, 2 Transcor tical Motor aphasics, and 1 Global aphasic. Aphasic participants were profiled using th e Western Aphasia Battery (WAB) (Kertesz, 1982) the Boston Naming Test (BNT)(Kaplan et al., 1983) the Reading Comprehension Battery for Aphasia (RCBA)(Lapointe et al., 19 79), and a non-standardized speech motor performance test which was used to identify th e presence or absence of apraxia of speech or dysarthria (Duffy, 2005). During the speech motor performance test participants were asked to repeat back to the investigator five increasingly longe r sentences which were verbally presented to each participant one at a time. The same five sentences were then presented again verbally 11

PAGE 12

and the participant was instructed to repeat the sentences back to the investigator but this time twice as fast. Participant responses were digitally recorded using a Marantz PMD671 Professional Compact Flash Recorder and Audiotechnica ATM 76 microphone. Participant responses were subjectively scored offline by the investigator to identify apraxic or dysarthric verbal errors according to the symptomology of th ese disorders presented within the literature. All participants completed a vision screening in wh ich a series of symbols were presented at the top of a computer screen and were asked to id entify the corresponding sy mbols at the bottom of the screen within a row of similar symbols by pointing. The symbols were presented in bold lowercase Arial font at 72 point centered on a white background. The normal control participants were assessed us ing the same standardized measures as the aphasia group with the exception of the WAB and the RCBA and were also given the MiniMental Status Examination (Folstein et al., 1975 ) and the National Adult Reading Test (NART) (Nelson, 1982). Item Stimuli Stimuli were developed for this project cons isting of 39 nouns (24 with regular spelling patterns, and 15 with irregular spelling patte rns), 30 nonwords and 12 pseudohomophones. Item stimuli are shown in Table 2-1. Four categories we re selected consisting of real words, irregular words, pseudohomophones, and nonwords. Differe nt selection criteria were used for the selection of words for each category based on data obtained from the MRC Psycholinguistic Database (Wilson, 1988). Real Word Stimuli The selection criteria for hierarchy of the real words was controlled according to word type and only nouns were selected. Word length was broken down into two levels, number of syllables, and number of graphemes and phonemes which was controlled within each syllable. 12

PAGE 13

For example one syllable words would have 3-4 graphemes/phonemes, two syllable words would have 4-6 graphemes/phonemes, three syllable wo rds would have 7-9 graphemes/phonemes, four syllable words would have 9 graphemes/phonemes and a five syllable words would have 10 graphemes/phonemes. The Thorndike-Lorge writ ten frequency was equated within and across all categories and all average va lues were within 1 standard de viation. The admissibility of clusters and blends was determined by word leng th with inclusion not permitted for short words and permitted for long words. All words were al so described for the age of acquisition rating, concreteness rating, familiarity rating, im agability rating, and the number of digraphs. Irregular Word Stimuli Irregular words were defined as words th at violate typical letter-sound patterns in English (Spear-Swerling et al., 2004). The selec tion criteria for hierarc hy of the irregular words was controlled according to syllable length and a ll words were 1-3 syllables in length because prior test batteries typically go to 3 syllables. Selection criteria also included the ThorndikeLorge written frequency and all words were divided into a high or low frequency subcategories with a high frequency range of 1-100 and a lo w frequency range of 800-2000. All words were also described for the age of acquisition ra ting, concreteness rating, familiarity rating, imagability rating, and the number of digraphs. Pseudohomophone Word Stimuli The primary criterion for the selection of the pseudohomophones was based on the Thorndike-Lorge written frequency. For this category, a 1 syllable real word was self converted into a pseudohomophone to determ ine the written word frequency. All words were divided into a high or low frequency subcateg ory with a high frequency range of 1-100 and a low frequency range of 800-2000. The pseudohomophones were also described for the age of acquisition rating, concreteness rating, familiarity rating, imag ability rating, and the number of digraphs. 13

PAGE 14

Nonword Stimuli Nonwords were created and controlled accord ing to the following hierarchy: consonant and vowel frequency and frequency values from Shriberg and Kent (1982) were used in the criteria selection. The frequency of the consona nts and vowels were divided into high and low frequency subcategories. For the vowels the high frequency range was greater than 7.0, the low frequency range was less than 4.0 and for the consonants the high freque ncy range was greater than 5.0 and the low frequency range was less than 2.0. Thus, all words in the high frequency category contained only high frequency consonants and vowels. Si milarly, all words in the low frequency category contained onl y low frequency consonants and vowels. One syllable, two syllable, and three syllable nonwords were cr eated using the repertoi re of consonants and vowels. Each syllable length category was also divide d into low and high frequency words. All nonwords had CV word initial. The sum and average of biphone probability using the Phonetic Probability Calculator (Vitevitch & Luce, 2004) was used calculate the sum of all biphone probabilities within each nonword. The average of the biphone probability for each category (e.g. 1-syllable, high frequency words) was also calculated. The number graphemes and phonemes was controlled within each syllable with one syllable nonwords having 3-4 graphemes/phonemes, two syllable nonwords havi ng 4-6 graphemes/phonemes and three syllable nonwords having 7-13 graphemes/phonemes Data Collection Procedure Stimuli within each stimulus category were randomized for presentation by computer software and were presented to the participants one at a time using a Dell Lattitude X1 Laptop. Participants were then asked to read each stimuli aloud. Stimuli were presented centered in the middle of a white screen in blac k, bolded, lowercase Arial font se t at 72 points. The order of 14

PAGE 15

presentation of stimulus categories were also rand omized within and across stimulus categories. Stimulus items were advanced automatically by the computer software using an inter-stimulus interval set at 8.0 seconds. Each stimulus item was advance to the next stimulus item without a transition interval. Scoring The inter-stimulus interval was used to ensure that test conditions were uniform across participants and participants responses to a stimulus item beyond 8.0 seconds were scored as incorrect. Only data on correct responses were analyzed. Responses to stimuli were recorded digitally and scored offline for accuracy and error type using a Marantz PMD671 Professional Compact Flash Recorder and Audiotechnica AT M 76 microphone. A response was scored as correct if it matched the target stimulus and did not contain an omissi on, addition, transposition or substitution error. Close approximations and distortions due to apraxia of speech, dysarthria or phonetic differences were scored as correct since they are consider ed by this design to involve motor speech planning, programming or execution level errors or differences and not linguistic planning or programming level errors. Incorrec t responses were defined as false starts, no response and presence of semantic and / or phonol ogic errors. Errors were scored as either a phonological error, a verbal error or an o ther error. For the purposes of this design a phonologica l error were operationally defined as a phonologic substitution error (e.g. one phoneme s ubsitition), a phonologic addition error (e.g. one phoneme), a phonologic omission error (e.g. one phomeme), a transposition or exchange error, a devoicing error or a voicing, a neologistic error wh ich was defined as a nonword involving multiple phonologic errors. A verbal e rror was operationally defined as a real word substitution error that was not semantically relate d to the target stimulus item, a regularization error, a pure semantic error (a real word substitu tion which was semantically related to the target 15

PAGE 16

stimulus), and a derivational error (the addi tion or omission of mor phologic endings). An other error was operationally defined as a ci rcumlocution (e.g. the thing you open / door), a compensatory error without corr ectly producing the word (e.g. c a t), no vocalization, an apraxic error (e.g. /ah, ah, ah/), a false start (e.g. d, d, d, dar, dart), a compensatory error (E.g. c a t spells cat), a distor tion (e.g. consontant and vowel im precision, or prolongation) or a stress error (e.g. A lly vs all Y ). 16

PAGE 17

17 Table 2-1. Item stimuli Real Words Irregular Words Pseudohomophones Nonwords lot chance fyte nis job laugh rhed reat red suit phine kes bin pew traine nush fib coup kupp thaun itch heir pset yane body office phinn dessy baby promise clinck simite city service jirm leedle melon ally rhigg junooge vigil nausea troall choithane boxer bodice kaud shounooth afternoon ratio tisadel president tentative sedeatin family rhapsody nysimin caramel shoinaejouth promoter chaythoinooth meteorite jounaethawn ultimatum diplomacy regulator disability imbecility generosity

PAGE 18

CHAPTER 3 DATA ANALYSIS Research Question One To answer research question one and to determ ine the prevalence and type of alexia within the aphasic group simple descriptive statistics including means, sta ndard deviations, and percentages for variables within normal, aphasic, and phonological /deep alexia subjects were used. The normal control groups mean and stan dard deviation was calculated for overall accuracy across word types. Any participant within the aphasia group whose overall accuracy score fell below two standard deviations of th e normal control groups mean was profiled by this analysis as having alexia. For each participant, accuracy across each word type was calculated. Each participant within the apha sia group identified with alexia was further profiled as having either surface, phonological or deep alexia based on the following criteria: If the participants nonword accuracy exceeded their regular word accu racy they were classified as having surface alexia. If the participants regular word accuracy exceeds their nonword accu racy or was equal to their nonword accuracy they were classi fied as having phonological/deep alexia. Research Question Two To compare the amount of verbal errors and the amount of ph onological errors among subjects with phonological/deep alexia, one-way repeated measures ANCOVA was used with the error type as the factor while controlling for age, gender, education, months post onset, and history of speech therapy using the Mixed procedure in SAS. To determine if there was a difference in read ing performance and moreover if there was a difference in reading performance across word types between normal subjects and aphasic subjects, a multivariate linear regression was used to account for the correlation due to simultaneous measurements on several dependent variables on a same subject. The dependent 18

PAGE 19

19 variables, total score, regul ar word, irregular word, pse udohomophone, and nonword sub total scores, were simultaneously related with the fact or group (normal or aphasic) while controlling for covariates age, gender, education, and history of speech therapy in one model using the GLM procedure in SAS. Scoring Reliability To examine the intra-rater scoring reliability and inter-rater scoring reliability, Kappa coefficients were calculated to describe the agreement in identifying correct responses to items and classifying error responses to items between two ratings by the same rater and the agreement between two different raters, respectively.

PAGE 20

CHAPTER 4 RESULTS Research Question One Most individuals (33 out of 41) with aphasia (80.49%) fell below 2 standard deviations of the normal reading group total mean (56.93, s.d. 6.16) and were classified as presenting with alexia. Descriptive statistics for variables among normal subjects are shown in Table 4-1 and normal total score distribution is shown in Figure 4-1. A number of individuals (8 out of 41) with aphasia (19.51%) fell within 2 standard deviations of the normal reading group mean and were classified as not presenting with alexia. Prevalence of alexia with in aphasia is shown in Figure 4-2. Of those individuals with alexia and aphasia, a ll (33 out of 33 or 100%) were determined to read regular words more accurately than nonwords and were subsequently classified as presenting with al exia of the phonological/deep type a nd no individual with alexia and aphasia (0 out of 33 or 0%) presente d with an alexia of the surface type. Research Question Two The results of comparing the amount of ve rbal errors and the amount of phonological errors among subjects with phonological/deep alex ia are shown in Table 4-2. Subjects with Phonological/Deep Alexia made significantly more phonological errors (p = 0.0004) than verbal errors after controlling for age, gender, months post onset, education, history of speech language therapy. Distribution of alexic readi ng error types are shown in Figure 4-3. There is a significant difference in total sc ore between the normal reading group and the subjects with aphasia after contro lling for gender, age, education and history of speech therapy. The effect of variables on reading performan ce are shown in Table 43. The subjects with aphasia had significant lower mean total score (26.117 less) than the normal reading group after controlling for covariates. Education is also sign ificantly positively associated with total scores 20

PAGE 21

(p= 0.005). MANOVA tests show that there is significant overall group (aphasic versus normal) effect (p < 0.0001) and overall educa tion effect (p= 0.0085) on total scores. There is a significant difference in Regular word, Irregular word, Pseudohomophone, and Nonword subtotal scores between the normal reading group and the subjects with aphasia after controlling for gender, age, education, and histor y of speech therapy. The subjects with aphasia had significant lower Regular word (7.765 le ss), Irregular word (6.787 less), Pseudohomophone (5.285 less), and Nonword (6.280 less) subtotal scores than the normal reading group after controlling for covariates. Education is also si gnificantly positively associated with Regular word (p= 0.015), Irregular word (p= 0.019), and Nonword (p= 0.0003) su btotal scores, and marginally significantly associated with Pseudohomophone (p= 0.059) subtotal scores. MANOVA tests show that there is significant over all group (aphasic versus normal) effect (p < 0.0001) and overall education effect (p= 0.0085) on all subtotal scores. Scoring Reliability Kappa coefficient (95% confidence interval) is 0.9764 (0.9702, 0.9825) and 0.9603 (0.9531, 0.9674) for the agreement between ratings by the same rater at different time on identifying correct responses to items and on cl assifying error responses to items, respectively, and is 0.9024 (0.8779, 0.9269) and 0.8462 (0.8197, 0.8727) for the agreement between ratings by different raters on identifying correct responses to items and on classifying error responses to items, respectively. These high kappa coefficients indicate strong agreement between ratings by the same rater at different time and between ratings by different raters. 21

PAGE 22

Table 4-1. Statistical pr ofile of normal subjects Variable N Mean SD % yes Age 29 61.66 9.72 Education 29 15.45 2.58 Female 29 62.07 SLP-history (yes) 29 6.90 Total score 29 56.93 6.16 22

PAGE 23

Figure 4-1. Distribution of to tal scores among the normal group Figure 4-2. Prevalence of alexia within aphasia 23

PAGE 24

Table 4-2. Covariate effect s in phonological/deep alexia Variable Coefficient SE P-value Intercept -1.940 9.704 0.843 Error Type (phonological) 15.000 3.790 0.0004 Gender (female) -3.883 3.003 0.207 Age 0.238 0.155 0.137 Education -0.188 0.481 0.699 SLP history (no) -0.272 3.323 0.935 Months post onset -0.011 0.022 0.612 Table 4-3. Variable effects on reading accuracy Variable Coefficient SE P-value Intercept 17.709 13.669 0.200 Group* (ref: normal) Aphasic -26.117 4.663 <.0001 Gender (ref: male) Female 2.265 3.584 0.530 Age 0.151 0.182 0.408 Education* 1.728 0.596 0.005 SLP history (ref: yes) no 1.916 4.260 0.655 MANOVA tests show significant overall group effect (P-value < 0.0001) and education effect (P-value = 0.0085) on total and all subtotal scores. 24

PAGE 25

25 Figure 4-3. Distribution by error type among the group of aphasics with alexia

PAGE 26

CHAPTER 5 DISCUSSION The purpose of this study was to describe the na ture and prevalence of alexia in aphasia. Our finding that alexia is common both within and across aphasic syndro mes is supported by the literature (Webb et al., 1983). We found that the reading performance of individuals with aphasia is typically impaired, and th at the severity but not the nature of this impairment is highly variable and associated with an individuals ed ucational experience. This finding is novel and will be discussed in further detail below. We found that phonological/deep alexia is the only central alexia associated with the aphasia gr oup and that the predominant reading error is phonological in nature. Research Question One: Prevalence and nature of alexia While a significant majority of individuals w ith aphasia had alexia we note that a number of individuals with aphasia scored well within two standard deviations of the normal range. While it is generally accepted that alexia can pres ent either as an isolated symptom or within the context of an aphasic syndrome we conclude on the basis of this study that no dependent relationship exists. We find that aphasia can present without significant impairment to the reading modality. In contrast a number of early group studies found that alexia always occurs within aphasia (Webb et al., 1983; Duffy et al., 1976), but this findi ng is controversial (Hoffmann et al., 1997; Nance et al ., 1981). We speculate that th e close association of alexia both within across aphasic syndromes and the finding that severity of aphasia is not significantly correlated with severity of alexia is suggestive either of a highly vulnerable or of a distributed cortical network for reading. This account is well supported by recent radiographic and neuroimaging studies of normal readers elsewh ere (Church et al., 2008; Mechelli et al., 2005). 26

PAGE 27

The finding that both the aphasic and normal groups read real words better than nonwords and that the aphasic group was generally impaired suggests a graceful degradation of the reading system. This aphasic pattern of reading perfor mance together with reading error analysis is consistent with earlier descriptions of phonological and deep alexia and is inconsistent with descriptions of surface alexia (C herney, 2004; Plaut et al., 1996). We account for this finding on the basis of the right hemisphere hypothesis (Coltheart, 2000; Hildebra ndt, 1994). Phonological alexia is prevalent because the right hemis phere usually lacks the substrate of phonological sequence knowledge that could compensate for the results of the left hemisphere lesion, whereas it is better equipped to support whole word r eading to some degree and thereby compensate surface alexia (Coltheart, 2000; Hildebrandt, 1994). We account for our finding that years of formal education is inversely associated with severity of alexia on the basis th at literate adults with greater educational experience may rely more on whole word reading routes than literate adults with less educatio nal experience. This account is supported by a number of aphasia group studies which found that severity of aphasia is inversely associated with years of form al education (Smith, 1971; Conor, 2000). Recent neuroimaging studies of children an d adults have also shown that literate adults rely less on phonological and auditory processes to read than children (Church et al ., 2008; Bitan et al., 2007). We speculate that decreased activati on of phonological and audi tory pathways during reading is due to increased reliance on whole wo rd reading routes suppor ted by semantics. It follows that adults with great er educational experience may have richer semantic support systems used for reading and will therefore be bette r protected from the effects of a neurological insult that interferes with phonological route processing. Th e finding that individuals with greater levels of educational experience make less reading erro rs under stimulus conditions that 27

PAGE 28

preclude whole word reading (nonwords) suggests that whole word readers also have fully mature phonological sequence knowledge. The use of whole word reading routes may be entirely conditional on underlying phonological e fficiency (Church et al., 2008; Bitan et al., 2007). It may be that degraded phonological effi ciency also implicates a degraded semantic system leading to phonologically base d reading errors and at its furthest extreme semantically based reading errors (Southwood et al., 2000). Th is point will be discussed in further detail below. Research Question Two: Predominant Error Type Our finding that individuals with phonological and deep al exia predominantly made phonological errors and not whole wo rd substitutions is unexpecte d. Earlier descriptions of phonological/deep alexia describe word substitutions as the defining ch aracteristic of this form of alexia (Southwood et al., 2000; Cherney, 2004; Cosl ett, 2000). Phonological and deep alexics have impaired phonological systems and only rela tively spared semantic systems. The finding that phonological errors ar e more prevalent during oral readin g is in line with the simultaneous activation hypothesis which hypothe sizes that simultaneous activa tion of competing impaired primary reading routes will overide the lexical/s emantic reading route sufficiently to activate a visually based or neologisti c phonological error (Southwood et al ., 2000). According to this hypothesis stimulus conditions which prohibit whole word reading (nonwords and unfamiliar word stimuli) will increase th e probability of phonological errors and semantic errors will only occur with severe damage to direct and indirect reading routes. At th e furthest extreme nonword reading will be entirely abolished. This is the case in deep alexia (Southwood et al., 2000). It may also be that phonological errors are more pr evalent than whole word substitutions because the right hemisphere usually lacks the substr ate of phonological sequenc e knowledge that could 28

PAGE 29

29 compensate for the results of the left hemisphere lesion, whereas it is be tter equipped to support whole word reading to some degree (Coltheart, 2000; Hildebrandt, 1994). Implication of Findings These findings can inform clinical practice in several ways. Since the majority of aphasics have alexia, it is suggested that initial testing in th e clinical environmen t should incorporate a reading evaluation in addition to traditional aphasia tests. While oral reading and reading for comprehension share neural mechanisms, at present, there is insufficient clinical data to support any conclusion that a significantly positive correl ation exists within this population. Since all individuals with alexia have phonol ogic alexia, treatment should be directed at the level of the phonologic processor. There is evidence in ap hasic literature that by treating the phonologic system, reading as well as speech production improves (Kendall et al., 2003; Kendall et al., 2006).

PAGE 30

LIST OF REFERENCES Bitan, T., Cheon, J., Lu, D., Burman, D.D., Gitelm an, D.R., Mesulam, M.M., Booth, J.R. (2007). Developmental changes in activation and eff ective connectivity in phonological processing. Neuroimage. 38(3) 564-75. Cherney, L.R. (2004). Aphasia, alexia, and oral reading. Topics in Stroke Rehabilitation. 11(1) 22-36. Church, J.A., Coalson, R.S., Lugar, H.M., Pe tersen, S.E., Schlaggar, B.L. (2008). A Developmental fMRI Study of Reading and Repetition Reveals Changes in Phonological and Visual Mechanisms Over Age. Cerebral Cortex. Advance Access Publication Jan 31 1-12. Coltheart, M. (2000). Deep dyslexia is right-hemisphere reading. Brain and Language. 71(2) 299-309. Coslett, H.B. (2000). Acquired dyslexia. Seminars in Neurology. 20(4) 419-26. Crisp, J., Lambon Ralph, M.A. (2006). Unlocki ng the nature of the phonological-deep dyslexia continuum: the keys to reading al oud are in phonology and semantics. Journal of Cognitive Neuroscience. 18(3) 348-62. Duffy, R.J. (2005). Motor Speech Disorders: substrates, differential diagnosis, and management ( 2nd ed.). St. Louis, MO: Elsevier Mosby. Duffy, R.J., Ulrich, S.R.(1976). A comparison of impairments in verbal comprehension, speech, reading, and writing in adult aphasics. Journal of Speech and Hearing Disorders. 41(1) 110-9. Folstein, M.F., Folstein, S.E., McHugh, P.R. (1975) Mini-mental state. A practical method for grading the cognitive state of patients for the clinician. Journal of Psychiatric Research. 12 (3) 189-98. Friedman, R.B. (1996). Recovery from deep alexia to phonological alexia: points on a continuum. Brain and Language. 52(1) 114-28. Glosser, G., Friedman, R.B. (1990). Th e continuum of deep/phonological alexia. Cortex. 26(3) 343-59. Hildebrandt, N. (1994) The Reicher-Wheeler effect and models of deep and phonological dyslexia. Journal of Neurolinguistics. 8(1) 1-18. Hoffmann, M., Sacco, R., Mohr, J.P., Tatemichi, T. K. (1997). Higher cortical function deficits among acute stroke patients: The stroke data bank experience. Journal of Stroke and Cerebrovascular Disease. 6(3) 114-20. Kaplan, E., Goodglass, H., Weintraub, S. (1983). The Boston Naming Test. Philadelphia, PA: Lea & Febiger. 30

PAGE 31

31 Kendall, D., Conway, T., Rosenbek, J., Gonzalez-R othi, L. (2003). Pho nological rehabilitation of acquired phonologic alexia. Aphasiology. 17(11) 1073-1095. Kendall, D., Rodriguez, A., Rosenbek, J., Conway, T., Gonzalez-Rothi, L. (2006). The Influence of Intensive Phono-Motor Rehabil itation of Apraxia of Speech. Journal of Rehabilitation Research and Development. 43(3) 323-336. Kertesz, A. (1982). The Western Aphasia Battery Austin, TX: PRO-ED Inc. LaPointe, L.L., Horner, J. (1979). Reading Comprehension Battery for Aphasia Austin (TX): PRO-ED Inc. Mechelli, A., Crinion, J.T., Long, S., Fris ton, K.J., Lambon Ralph, M.A., Patterson, K., McClelland, J.L., Price, C.J. (2005). Dissociating reading pro cesses on the basis of neuronal interactions. Journal of Cognitive Neuroscience. 17(11) 1753-65. Nance, A.L., Ochsner, G.J. (1981). Language modality performance patterns in aphasia. Journal of Communication Disorders. 14(5) 421-8. Nelson, H.E. (1982). National Adult Reading Test. Windsor, UK: NFER-Nelson. Plaut, D.C., McClelland, J.L., Seidenberg, M. S., Patterson, K. (1996). Understanding normal and impaired word reading: computational principles in quasi -regular domains. Psychological Review. 103(1) 56-115. Southwood, M.H., Chatterjee, A. (2000). The inter action of multiple routes in oral reading: evidence from dissociations in naming and oral reading in phonol ogical dyslexia. Brain and Language. 72(1) 14-39. Spear-Swerling, L., Brucker, P.O. (2004). Preparing novice teachers to develop basic reading and spelling skills in children. Annals of Dyslexia. 54(2) 332-64. Vitevitch, M.S., Luce, P.A. (2004). A web-base d interface to calculate phonotactic probability for words and nonwords in English. Behavior Research Methods, Instruments, and Computers. 36, 481-487. Webb, W.G., Love, R.J. (1983). Reading problems in chronic aphasia. Journal of Speech and Hearing Disorders. 48(2) 164-71. Wilson, M.D. (1988). The MRC Psycholinguistic Database: Machine Readable Dictionary, Version 2. Behavioural Research Methods, Instruments and Computers. 20(1) 6-11.

PAGE 32

BIOGRAPHICAL SKETCH Jonathan Paul Wilson was born in 1971, in Bangor Northern Ireland. He is the eldest son of two children and grew up in Bangor, a seaside town on the east coast of Ireland. He attended primary school in Bangor and graduated from hi s grammar school, the Royal Belfast Academical Institution, in Belfast in 1989. He graduated fr om the Queens University of Belfast in 1992 with an honors degree in English language and literature. He went on to study computing and information systems at the University of Ulster where he received his post graduate diploma in computing and information systems in 1998. Upon graduating he joined the Royal Bank of Scotland (UK) where he worked as a computer systems engineer and later as an accoun t executive. In 2005 he relocated to Florida, USA where he joined the University of Flor idas masters program in the Department of Communication Sciences and Disorders, majoring in speech-language pathology. Upon completion of the masters program Jonathan intends to pursue clinical certification as a speechlanguage pathologist and will con tinue his clinical research into the PhD program at the University of Florida starting in Fall 2008. His current res earch interests include adult neurogenic communication disorder s and the study of anomia.