Linguistic semantic agraphia: A dissociation of the lexical spelling system from semantics

BRAIN

AND

LANGUAGE

27, 257-280

(1986)

Linguistic Semantic Agraphia: A Dissociation of the Lexical Spelling System from Semantics DAVID P. ROELTGEN Department

of Neurolog!,

Uni\,ersity

of Missouri-Colllmhirr

AND

LESLIE GONZALEZ Departments

of Neurology,

College

ROTHI AND KENNETH

of Medicirre, Center, Gaine5

M.

and Veteran’s vi//r

HEILMAN Administration

Medical

Two spelling systems have been described. The phonological system transcodes speech sounds to letters and is thought to be useful for spelling regular words and pronounceable nonwords. Although the second system, the lexical-semantic system, is thought to use visual word images and meaning to spell irregular words. it is not known if this system is dependent on semantic knowledge. We used a homophone spelling test to examine the lexical-semantic system in five patients. The patients were asked to spell individual homophones (doe or dough) using the context of a sentence. Semantically incorrect and correct homophones were spelled equally well, whether they were regular or irregular. These results demonstrate that an irregular word may be spelled without knowledge of the word’s meaning. Therefore, the lexical system can be dissociated from semantic influence. 6 19% Academic Prar. Inc.

Two parallel systems have been described for oral and written spelling, one lexical and one phonological (Beauvois & DtkouesnC, 1981; Shallice, 1981; Ellis, 1982; Bub & Kertesz, 1982; Hatfield, 1982; Roeltgen, Sevush, & Heilman, 1983; Roeltgen & Heilman, 1984). The phonological system transcodes speech sounds to letters and is thought to be particularly useful for spelling orthographically regular unfamiliar words and proThis paper was presented in part at the 107th Annual Meeting of The American Neurological Association, Washington, DC, September 1982. The authors thank an anonymous reviewer for helpful suggestions on a previous draft and Cindy Cover for manuscript preparation. Address correspondence and reprint requests to Dr. David P. Roeltgen, Department of Neurology, University of Missouri-Columbia, Columbia, MO 65212. Dr. Roeltgen received support from a Teacher Investigator Development Award NS 00807 from the NINCDS. 257 0093-934X186

$3.00

CopyrIght c 1986 by Academic Presr. Inc. All nphts of reproduction in any form rexwed.

258

ROELTGEN,

GONZALEZ

ROTHI,

AND

HEILMAN

nounceable nonword letter strings (e.g., jig, blimpkin) (Beauvois & DCrouesne, 1981; Shallice, 1981; Bub & Kertesz, 1982; Roeltgen et al., 1983; Roeltgen & Heilman, 1984). The lexical system is important for spelling familiar words, particularly words which are orthographically irregular (words that cannot be spelled by direct speech sound to letter (phoneme to grapheme) conversion (e.g., weapon)) and ambiguous (words having speech sounds that can be spelled by more than one potential letter (e.g., cotton, ciry) (Beauvois & Derouesne, 1981; Roeltgen & Heilman, 1984). The lexical system is thought to use a whole word accessing system involving a visual system (Hatfield, 1982) or visual word images (Roeltgen et al., 1983). These two systems are thought to be necessary for correct letter selection for both oral spelling and writing (Ellis, 1982; Hatfield, 1982; Roeltgen & Heilman, 1984). Disruption of either of these spelling mechanisms by acquired brain lesions results in particular patterns of disability and residual ability. In most patients with normal motor functions, including limb praxis, the patterns of disability and residual ability are expressed similarly in oral spelling and in writing (Ellis, 1982; Roeltgen, Cordell, & Sevush, 1982; Roeltgen & Heilman, 1984). Consequently, the term spelling has been used to indicate either oral spelling or writing (Roeltgen et al., 1982; Hatfield & Patterson, 1983). Patients who lose lexical spelling ability have difficulty spelling irregular and ambiguous words but retain ability to spell nonwords and regularly spelled real words (Beauvois & Derouesne, 1981; Roeltgen & Heilman, 1984). These patients are said to have lexical agraphia and typically have lesions affecting the posterior angular gyrus (Roeltgen & Heilman, 1984). Patients who lose phonological spelling ability are unable to spell nonwords or regularly spelled unfamiliar words, but retain ability to spell familiar words, including orthographically irregular and ambiguous words (Shallice, 1981; Roeltgen et al., 1983). These patients are said to have phonological agraphia and typically have lesions affecting the supramarginal gyrus or the insula deep to it (Roeltgen et al., 1983; Roeltgen & Heilman, 1984). Patients with phonological agraphia are able to spell meaningful words but not meaningless words, suggesting a close relationship of semantics with the preserved lexical system (Shallice, 1981; Roeltgen et al., 1983). Because of this close relationship, the lexical system has been termed lexical semantic. Although patients with phonological agraphia, who spell using the preserved lexical system, are only able to spell meaningful words, it is not clear if meaning (semantics) is dissociable from the visual word images (lexical writing system). It is possible that some patients might spell irregular meaningful words (use the lexical system) without use of semantic knowledge. Such patients would indicate that meaning may not be necessary to activate these word images. We describe five patients who demonstrate that the lexical spelling system (visual word images) may be dissociated from semantic influence

SEMANTIC

AGRAPHIA

259

(meaning). With the use of a homophone spelling test, we demonstrated that all five patients spelled irregular words but had difficulty incorporating meaning into what they spelled. CASE REPORTS Patient 1

This 62-year-old, right-handed male, who was educated through the I Ith grade, had been a good student and a good speller. He was admitted to the hospital because of difficulty using his right arm and mumbled speech. On neurological examination, he had mild to moderate paresis and a sensory deficit involving his right arm. He had right-sided hyperreflexia and a right extensor plantar response. His spontaneous speech was moderately nonfluent, consisting of short propositional sentences with normal syntax. He made no phonemic paraphasic errors and rare semantic paraphasic errors. His comprehension of speech was moderately impaired, especially for complex commands (e.g., point to the comb with the pen) where meaning was dependent upon accurate processing of syntax. Repetition of speech was almost normal. Object naming was moderately impaired with frequent semantic paraphasic errors. The results of the Western Aphasia Battery (WAB) (Kertesz, 1980) (Table 1) were consistent with either a transcortical sensory aphasia or mixed transcortical aphasia. He had no left-right disorientation and no ideomotor apraxia. His ability to calculate was moderately impaired, and his ability to name fingers was poor. He read words and sentences aloud flawlessly but his reading comprehension was limited to single words. His writing was sloppy, but most letters were legible. He was able to write dictated commands which he was unable to follow (e.g., point to the comb with the book). His written spelling was the same as his oral spelling. He spelled correctly 70% of words and 80% of pronounceable nonwords dictated to him. Computerized tomography (CT) initially was normal. Repeat CT demonstrated a small subcortical lucency in the left parietal lobe. Clinical and radiographic evidence suggested a left hemispheric watershed infarction. Patient 2

This 48-year-old, right-handed college educated male was examined approximately 2 weeks after a presumed subarachnoid hemorrhage that was accompanied by severe vasospasm. On neurological examination, he had moderate weakness of his right arm and the lower right half of his face. His spontaneous speech was telegraphic with very rare simple propositional sentences. He made no phonemic paraphasic errors and occasional

260

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AND

HEILMAN

semantic paraphasic errors. His comprehension was very poor; he had difficulty responding correctly to yes/no questions and followed only some simple commands. His repetition was almost flawless. Naming to confrontation was severely impaired and he made frequent semantic paraphasic errors. His results on the WAB (Kertesz, 1980) (Table 1) were consistent with a mixed transcortical aphasia. He had ideomotor apraxia, left-right disorientation, dyscalculia, and finger agnosia. He read words and sentences aloud flawlessly but was unable to comprehend them. He was unable to write to dictation. He made poorly formed and illegible graphemes suggesting apraxic agraphia. However, he was able to properly hold a pen. He spelled correctly more than 80% of words and nonwords dictated to him. CT demonstrated a subcortical area of decreased attenuation in the left hemisphere. It involved the white matter deep to the midfrontal gyrus, a portion of the head of the caudate, and the anterior limb and genu of the internal capsule. Patient 3 This 50 year old right-handed male, who was educated through the ninth grade, had been a good speller and a good reader. He was admitted to the hospital because of a 2- to 3-week history of inability to care for himself and confusion. On neurological examination he had no motor or sensory abnormalities. His spontaneous speech was moderately nonfluent. It consisted of speech that was intermittently telegraphic, consisting predominantly of TABLE 1 RESULTS OF THE WESTERN APHASIA BATTERY (KERTESZ,

Information content Fluency Comprehension Yes/no questions Auditory word recognition Sequential commands Total Repetition Naming Object naming Word fluency Sentence completion Responsive speech Total

1

Patient

Range

Patient

O-10 O-20

4 5

3 4

4 4

4 3

9 9

O-60

48

39

51

57

60

O-60

56

12

53

58

56

O-80 O-10 O-10

28 6.6 9.6

59 8.2 9.0

54 8.4 8.3

45 8.0 9.3

O-60 O-20

45 0

54 0

25 4

52 12

O-10 O-IO O-10

10 6 6.1

8 10 7.2

10 9 4.8

8 10 8.2

4 2.8 9.9 13 0 6 4 2.3

2

Patient

3

1980) Patient

4

Patient

5

SEMANTIC

AGRAPHIA

261

single words and occasional automatic sentences. He occasionally produced more complete propositional sentences with normal syntactic patterns. He made frequent semantic paraphasic errors and rare phonemic paraphasic errors. His comprehension of speech was mildly to moderately impaired, especially for complex commands where meaning was dependent upon accurate processing of syntax. Object naming was also mildly to moderately impaired. However, at the time he was examined on the WAB (Kertesz, 1980) (Table 1) his results were most consistent with a transcortical motor aphasia. He had mild left-right disorientation but no ideomotor apraxia. He had a moderate dyscalculia. He read aloud most single words and many sentences. His reading comprehension was similar to his speech comprehension. He was able to spell aloud 75% of words and 65% of nonwords dictated to him. He was asked to spell aloud and to write similar lists of words and there was no difference between his writing ability and his oral spelling ability. On CT he had a small area of hemorrhage in the left thalamus. Patient 4 This 52-year-old white male, who was educated through high school, had been a good speller and a good reader. He was diagnosed as having had a left hemispheric cerebral infarction three months prior to his evaluation. On neurological examination he had very mild right-sided hemispatial neglect. His spontaneous speech was intermittently nonfluent. He was frequently paragrammatic in his speech but occasionally produced complete propositional sentences with normal syntax. He made occasional to frequent semantic paraphasic errors but made no phonemic paraphasic errors. His comprehension of speech was mildly impaired, especially for complex commands where meaning was dependent upon accurate processing of syntax. Object naming was severely impaired. However, at the time he was examined on the WAB (Kertesz, 1980) (Table 1) his results were most consistent with a transcortical motor aphasia. He had no ideomotor apraxia. He read aloud most single words but had some difficulty reading sentences aloud. He had a mild impairment of single-word reading comprehension and had a severe impairment of comprehension of written sentences, as tested by the Reading Comprehension Battery for Aphasia (RCBA) (La Pointe & Horner, 1979). He was able to spell aloud 52% of words and 40% of nonwords dictated to him. Many of the correctly spelled words were orthographically irregular. When asked to spell aloud and to write similar lists of words he demonstrated significantly more difficulty in his writing ability compared to his oral spelling ability. On CT he had evidence of an ischemic infarction that was predominantly subcortical in nature and involved the anterior aspects of the basal ganglia, part of the anterior internal capsule, and much of the lower insula. A

262

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ROTHI,

AND

HEILMAN

second small area of apparent ischemic infarction involved the subcortical white matter adjacent to the posterior superior temporal gyrus. Patient 5

This 53-year-old, right-handed male, who was educated through the 10th grade, had been an excellent speller and a good reader. He had been diagnosed 6 months previously as having had an ischemic infarction of the left hemisphere. On neurological examination at the time of his evaluation he had mild right arm weakness. His spontaneous speech was fluent with good syntactic patterns. He made occasional semantic paraphasic errors and very rare phonemic paraphasic errors. His comprehension of speech was mildly impaired and his repetition was mildly to moderately impaired. His naming was moderately to markedly impaired, and he made frequent semantic paraphasic errors. His scores on the WAB (Kertesz, 1980) were consistent with an anemic aphasia (Table 1). He had no limb apraxia. He read aloud most single words and 50% of nonwords. He was able to spell aloud 58% of real words and 55% of nonwords dictated to him. Many of the correctly spelled words were orthographically irregular. He was asked to spell aloud and to write a similar list of words, and there was no difference between his writing ability and his oral spelling ability. On CT he had evidence of an ischemic infarction involving the frontal operculum, the anterior insula, the mid-frontal gyrus, part of the anterior limb of the internal capsule, and part of the caudate nucleus. SPECIAL

Battery of Linguistic Roeltgen, Cordell, Methods

TESTS

Analysis for Writing & Sevush, 1983

and Reading

(BLAWR)

All patients were given most portions of the BLAWR. The BLAWR contains 20 nonwords; 45 orthographically regular and 45 irregular nouns matched for length, frequency, and imageability; 30 nouns of high imagery and 30 of low imagery matched for length and frequency; 40 nouns and 40 function words matched for length and frequency; and 10 nouns each of high, medium, and low ambiguity matched for length, frequency, and imageability. The BLAWR was revised after the first two patients were studied, therefore the total number of regular and irregular nouns and nouns and function words was less for these patients than for Patients 3-5. However, the words used for Patients 1 and 2 were a subset of the words used for Patients 3-5. Patient 1 was not tested with the matched nouns and function words and Patient 2 was not tested with the nouns of high and low imagery.

Methods

of Analysis

For the BLAWR to word type.

the responses

were scored

as correct

or incorrect

and tabulated

according

SEMANTIC

AGRAPHIA

263

The results for spelling on the BLAWR are listed in Table 2. Patients 2 and 4 had varying degrees of impaired writing, usually due to motor dysfunction, weakness, or apraxia. Therefore they spelled better than they wrote, and their oral spelling results were recorded. Patients 3 and 5 orally spelled and wrote many of the same word lists within the BLAWR and showed no difference between the two modalities. Patient 1 refused to write more than a limited sample. Full testing was completed for oral spelling on Patients I, 3, and 5: therefore these results are recorded. Homophone

Spelling Test

In order to learn if these patients could spell words without knowledge of the words’ meanings, they were given a homophone spelling test. Homophones are words with identical phonology but with different meanings. A homophone’s meaning is dependent on the spelling (e.g., no/ and knor) and not its phonology. A list of homophones was dictated to each patient, and the patients were asked to orally spell their responses. Patient 3 was also asked to write his responses during a separate trial. Each homophone was followed by a sentence demonstrating the word’s meaning. For example. the patient was told, “Spell /nut/ as in ‘He is ~ro( here.’ ” The list included homophones with both orthographically regular spelling (e.g.. 110) and irregular spelling (e.g.. knorr,). A homophone was considered irregular if it fulfilled either of two criteria: first, if it had unpronounced consonants (e.g.. the h in pl~rnh): second. if the correct spelling for a phoneme was not the most common spelling for that phoneme (e.g.. for the phonetic sequence /led/, I-(2-d is regular. I-r-u-d is irregular). Many of the irregular homophones had unique speech sound to letter correspondences (e.g., colo~zc~l). Early in the evaluation of the first patient. we noted that uncommon words (e.g.. /rritr and cr~tr) appeared to be spelled more often than we expected on the basis of theit frequency of occurrence in general usage. In order to learn if these preliminary observations were correct, we compared the frequency of correct patient responses with a calculated expected frequency of response. We defined this expected frequency as the frequency expected if the homophones were spelled purely on the basis of their frequency in written English usage. This calculated expected frequency reflects the relative frequency of occurrence of each word within a given homophonic group. If the choice of an individual homophone by our patients is dependent on the homophone’s relative frequency of occurrence (compared to its associated homophone), then it would be expected that the response of our patients would reflect this frequency. Such a relationship might be expected if words are stored in and accessed from the area of visual word images on the basis of the frequency with which an adult is exposed to the written word. This expected frequency was calculated using the data of Thorndike and Lorge (1944) and was expressed as a percentage relative frequency of occurrence. (e.g.. the frequency of occurrence in written English usage for cash is 46 per million words and for c~c~/re I per million words (Thorndike & Lorge. 1944)). Since these are the only correct spellings for the phonetic sequence /kaes/, the sum of their percentage frequency of occurrence must equal 100, with cash occurring 98% of the time and cache 2%. The Thorndike and Lorge list is a listing of the approximate frequency that people might be exposed to written words. This information is important for this study because it has been suggested that the visual word images of the lexical-semantic system are developed from visual exposure (Roeltgen et al., 1982). Although there are more recent frequency indices than Thorndike and Lorge (1944). the relative frequencies calculated in this study are only approximations.

80 65 40 40

:‘i 4 5f

58 93 47 73

67

OF LINGUISTIC

51 73 24 53

87

Orthographically”,d irregular

FROM THE BATTERY

Orthographically”,” regular

OF WORDS

TABLE

-73 53 73

93

Highb imagery

ANALYSIS

2

83 40 57

73

Lowh imagery

FOR WRITING

READING

92 90 46 88

Nouns’

AND

100 92 68 62

-

Function’ words

(ROELTGEN,

100 90 80 100

70

Low

CORDELL,

Medium

100 60 80 90

70

1982)

80 90 70 80

90

High

words”.d

SEVKJSH,

Ambiguous

AND

y Matched for length, frequency and imageability. ’ Matched for length and frequency. ’ Matched for length, frequency and orthographic complexity. ’ Previously published (Roeltgen & Heilman, 1984). e These patients all had varying degrees of impaired writing. Results were obtained by oral spelling. ’ These patients were instructed to orally spell and write many of the same tests. They showed no difference between spelling and writing. The results recorded are for oral spelling.

80

Nonwords

ABILITY

1’

Patient

SPELLING

SEMANTIC

265

AGRAPHIA

used to compare, in a general way, frequently occurring homophones (cash) and infrequently occurring homophones (cache). Utilizing this frequency information, we divided the homophones into two genera1 groups, frequent (high frequency) and infrequent (low frequency). A homophone was considered frequent if its relative frequency of occurrence was equal to or greater than 40%. Forty percent was chosen because some homophone groups (e.g., /sent/) have more than two spellings. For these few groups of homophones, the most frequent spellings occurred in the range of 40 to 50% (e.g., dent 49%, cent 43%, and scent 8%).

Methods

of Analysis

We scored the number of correct and number of incorrect responses. Within the correct responses we compared the number of correct irregular homophones with the number of correct regular homophones. We also compared the number of correct high-frequency homophones and the number of correct low-frequency homophones. Therefore there are four combinations of correct responses: high-frequency regular. low-frequency regular, high-frequency irregular, and low-frequency irregular. In each category of correct responses we calculated the percentage correct in that category (e.g., percentage correct high-frequency regular homophones). This percentage was compared with the mean relative frequency of occurrence. This was done in order to determine if our patients spelled homophones in each group more or less often than would be expected based solely on the relative frequency of occurrence. In order to make certain that results were not significantly affected by word length, the mean word length was calculated for each homophone group. The mean length for high- and low-frequency irregular words was 4.8 letters. For low-frequency regular words it was 4.0 letters and for high-frequency regular words it was 3.5 letters. We also analyzed the incorrect responses and recorded the number of correctly spelled but semantically incorrect homophones (e.g., a response of k-n-o-t for not). We also performed an error analysis on the misspelled homophones and on the correctly spelled but semantically incorrect homophones. The former were analyzed for misspellings. phonologically and semantically incorrect words, and for phonologically correct pseudohomophones (e.g.. stimulus IIOSP, response knose). The latter were analyzed for word class changes between the stimulus and response.

The five patients correctly spelled the correct homophone on 43% of trials (Table 3). They correctly spelled an incorrect homophone (seTABLE RESULTS

3

OF THE HOMOPHONE

SPELLING

TEST

Patient number lb correct Semantically incorrect (correctly spelled)

44(50/l 14)” 42(48/ 114)

2h .40(46/116) 37(43/116)

3’ 53(59/112) 26(29/112)

4b 28(32/113) 24(27/113)

9

Mean % of 5 patients

49(56/114) 28(32/114)

43 31

’ Results expressed as % and (number correct/number given). ’ Oral spelling results. ’ Written results (oral spelling results: correct, 52% (58/l 12): semantically incorrect, 33% (37/l 12).

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mantically incorrect) (e.g., knot for not) on 31% of trials. The responses on the remaining 26% of trials were incorrect words or misspellings (see Table 5 for sample responses). For Patients 1, 2, 4, and 5, the results recorded in Table 3 reflect oral spelling. For Patient 3 the results reflect writing. Patient 3 also orally spelled the same words with very similar results (Table 3, Footnote c). However, the actual data were lost before the analysis was performed. Therefore, because the written and oral results were similar and the error analyses (Tables 5, 6 and 7) reflect the written responses, the written results were emphasized in Table 3. When compared to their mean relative frequency of occurrence, lowfrequency irregular homophones (e.g., knot) were spelled correctly most often as a group. Our patients were correct on 25% of trials with lowfrequency irregular homophones compared to a mean relative frequency of occurrence (calculated expected frequency) of 12% (Table 4). Therefore, the homophones in this group were spelled correctly approximately twice as often as would be predicted based on frequency alone. In contrast, high-frequency irregular homophones were spelled correctly least often relative to their calculated expected frequency. Our patients were correct on 43% of trials, better than they were with low-frequency irregular homophones (25%). However, this correct response rate of 43% is less than would be predicted based on the calculated expected frequency for this group of homophones (68%). Low-frequency regular homophones were spelled correctly on 29% of trials, or twice the calculated expected frequency of occurrence, which is 15%. High-frequency regular homophones were spelled correctly on 64% of trials. Again, high-frequency homophones were spelled less often than would be predicted based on the calculated expected frequency of occurrence for this group (70%). In calculating the relative frequency, it was assumed that the numerical results reflect the relative frequency of occurrence of words within a homophone group (e.g., knot and not) as well as across homophone groups (e.g., dough and might are both classified as high-frequency irregular words relative to their counterparts doe and mite). However, the second assumption is not always valid for the words included in our lists (e.g., dough occurs 11 per million and might has an AA frequency) (Thorndike & Lorge, 1944). Since such discrepancies might influence the final results, the results for each patient were also calculated after certain homophone combinations that might inappropriately influence the results were excluded. Two classes of homophone combinations were excluded. The first class consisted of pairs of homophones that were both of high absolute frequency (greater than 44 per million) but when compared to one another yielded a homophone of high relative frequency and one of low relative frequency (e.g., bowled and bold). Correct responses to the latter word would

for all

64

12 58 14 (76) SO 61

9% correct

91

70

70 70 70 70 70

(e.g..

regular not)

57

29

37 28 35 (32) 17 26

193

4

IS

IS 1s I5 IS 1s 43

--~~~~~~~

Orthographically

r-elative

63 frequency

6X

68 6X 69 69 68

Mean relative frequency of occurrence

High frequency (e.g.. write)

3X iI 61 (58) 17 69

% correct

to the mean

OF HOWPHONES

Mean relative frequency of occurrence

Low frequency (e.g., mite)

homophones

correct

TABLE SPELLING

Norr. Results are by homophone group. The percentage correct are compared in that group. ’ Calculated from Thorndike and Lorge (1944). ’ Results are oral spelling. ’ Results recorded are written results and (orally spelled results). d (Mean % correct)/(mean relative frequency of occurrence) x 100.

% Expected”

9 Mean

,‘I

Ih 2h

Patient

~-_-~

Mean relative frequency of occurrence0

High frequency (e.g., not) --~

Orthographically

CORRKT

25

23 28 30 (28) 31 12

12

of the homophones

20x

I2 12 12 12 12

Mean relative frequency of occurrence

Low frequency (e.g.. n~right) ~~__.~~~

homophones

% correct

of occurrence

irregular (e.g.. Xwt) ~~~~~-

TABLE

5

him lens insight bough doe dough plum plumb been bingh hoop hop

cord doe climb wright write right led lead knows now scene cene

2

ON THE HOMOPHONE

Nofe. Oral spelling for Patients 1, 2, 4, and 5, writing for Patient 3.

Correct 1. High-frequency regular 2. Low-frequency regular 3. High-frequency irregular 4. Low-frequency irregular B. Incorrect a. Stimulus 1. Correctly spelled but Response semantically b. Stimulus incorrect Response 2. Incorrect a. Stimulus words or Response misspellings b. Stimulus Response

A.

1

SAMPLE RESPONSES TEST

cash cache cache cash been bend isle ile

hole nun might lead

3

Patient number

SPELLING

not knot might mite seen seen knows knoze

burrow bold where hymn

4

hare hair gilt guilt insight ensite nit knight

cash kernel wrap awl

5

E

2 “> 5 8 P

g

-Q A 5 5 c E

F 3

F5

SEMANTIC

TABLE 6 ERROR PATTERNS FOR MISSPELLED

Patient I 2 3 4 5

6 5 6 I3 4

I6 27 24 54 28

HOMOPHONES“

Phonologically and semantically incorrect real words

Phonologically correct pseudohomophones”

Total

269

AGRAPHIA

(38) (18) (25) (24) (14)

1 5 8 IO

No responses

Misspellings’

(6) (18) (33) (18)

7 17 6 30 17

6 (21)

2 (12) 0 0 I (2) I (4)

(44) (63) (251 (56) (61)

a Absolute number and (%) of total errors (oral spelling for Patients 1. 2. 4. and 5. writing for Patient 3). ’ Phonology same as stimulus words (e.g., stimulus nose, response Xnoze). ’ Omissions, additions, inversions, substitutions, neologisms.

artificially raise the correct response rate for low-frequency homophones. The second class consisted of pairs that were both of low absolute frequency (less than 20 per million) but when compared to one another yielded a homophone of relative high frequency and one of relative low frequency (e.g., guilt and gilt). Incorrect responses to the former word would artifically lower the number of high-frequency homophones. These exclusions eliminated eight pairs of homophones. When these pairs were eliminated, the results did not significantly change (e.g., mean homophones spelled correctly (all patients): high-frequency regular: 65%; low-frequency

WORD

TABLE 7 CLASS AND IMAGERY CHANGES FOR CORRECTLY SEMANTICALLY INCORRECT HOMOPHONES’

SPELLED,

Imagery

Patient 1 2 3 4 5

Noun to verb

Verb to noun

3 4 4 1 4

2 6 4 5 4

Noun to adjective 1 2 2 2 1

Adjective to noun 1 2 1 3 1

Noun to noun

High to low

Low to high

9 13 13 7 16

7 9 8 1 9

6 10 I 4 7

Note. Other changes, including adjective to verb, verb to adjective, verb, verb to function word, verb to verb, adjective to adjective, were than 1 per patient). ’ Stimulus, lead [noun]; response, led [verb].

Noun to function word 1 1 1 I 0

Function word to noun 0 2 2 1 3

function word to rare (mean of less

270

ROELTGEN,

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regular: 28%; high-frequency irregular: 41%; low-frequency irregular: 24%; and mean relative frequency of occurrence (all patients): highfrequency regular: 70; low-frequency regular: 10; high-frequency irregular: 64; low-frequency irregular 8). Since exclusion of these homophone pairs did not affect the results, the reported results contain data from these homophones (Table 5). Error analysis of misspelled homophones indicates that all patients produced pseudohomophones, incorrect words, and misspellings, but only rarely did they not attempt to respond (Table 6). Analysis of word class changes for correctly spelled, semantically incorrect homophones indicates that changes between word classes were common without any definite pattern, except perhaps for Patient 4 who showed a tendency to spell nouns rather than verbs or adjectives and nouns of high imagery rather than nouns of low imagery (Table 7). Special Comprehension Tests

Methods 1 and 2. No special comprehension tests were given to Patients 1 and 2. 3. Patient 3 was given a modification of the homophone test from the Battery of Adult Reading Function (BARF) (Rothi, Coslett, & Heilman, 1983). The patient was asked to write 40 dictated homophones under two conditions. Under one condition a sentence containing the homophone was subsequently dictated to the patient. Under the other condition the patient was shown a picture in order to help him distinguish the homophone. Eight of these homophones were the same as those in the homophone spelling test. The results were scored the same as for the homophone spelling test. Patient 4. (a) The patient was asked to give a semantically equivalent synopsis of the sentence presented to him as part of the homophone spelling test. (b) He was asked to spell 100 homophones under three conditions. These homophones were a subset of those on the homophone spelling test. In each condition the word was dictated to the patient, and he was asked to spell it. The first condition was that used in the homophone spelling test. In the second condition, the dictated homophone was accompanied by a picture illustrating the correct homophone. In the third condition, the dictated homophone was accompanied by a written sentence with a blank space where the homophone belonged. The results for Conditions l-3 were scored in the same way as for the homophone spelling test. (c) He was required to choose the correct written homophone (two conditions) or the correct picture (two conditions) after the homophone was dictated. When asked to choose the written homophone he had a sentence dictated to him in the first condition and he was shown a picture in the second condition. When asked to choose the correct picture, the patient was shown the written homophone in the first condition and had the homophone spelled to him in the second condition. The same 100 homophones as in task b (spelling homophones) were used. Patient 5. (a) A subset of the homophones from the homophone spelling test was used for Patient 5 in the same way as the BARF (Rothi et al., 1983) was used for Patient 3. (b) In the homophone spelling test he had 28 correctly spelled but semantically incorrect responses. For each of these incorrect responses, the patient was asked to supply a sentence synonymous with the stimulus sentence, or in some other way demonstrate comprehension of the dictated sentence. Pafients Patient

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Results The results of the special comprehension tests are listed in Table 8. Patient 3’s ability to spell the correct homophone improved when the dictated homophones was accompanied by a picture rather than a dictated sentence. Patient 4 had difficulty spelling homophones regardless of conditions. In addition, except when asked to choose the correct picture when reading a homophone, he was barely above chance when asked to choose written homophones or pictures. Patient 5 showed a clear understanding of all but three of the sentences. On most of the trials, even though he was able to express a sentence or phrase synonymous with the stimulus sentence, he still produced a semantically incorrect homophone. In addition, when he spelled homophones, there was no difference whether the semantic stimulus was a picture or a dictated sentence. DISCUSSION

Each of our patients was right-handed and had a left hemispheric lesion resulting in an aphasia that included disturbed comprehension. Three of our patients had either a hemiparesis or apraxia that limited their writing. However, they all correctly spelled aloud many words. Two patients spelled aloud and wrote with equal ability. All patients spelled correctly many words that were orthographically irregular. Many of the correctly spelled irregular words had unique speech sound to letter correspondence (e.g., yacht, buss /bes/, and colonel). All patients also spelled many pronounceable nonwords correctly. Each patient was given a homophone spelling test and correctly spelled many semantically incorrect homophones. One patient performed equally well on this test, whether he responded by spelling or writing. All patients also spelled low-frequency irregular homophones almost as often as high-frequency irregular homophones. It has been postulated that semantics interacts with the speech mechanism through the area of auditory word images (Wernicke’s area) (Heilman, Tucker, & Valenstein, 1976; Heilman, Rothi, McFarling, & Rottmann, 1981). This hypothesis has been extended to spelling by Roeltgen et al. (Roeltgen & Heilman, 1983; Roeltgen et al., 1983) who suggested the model for spelling shown in Fig. 1. However, there is evidence to suggest that semantics may influence the lexical-semantic writing (spelling) system directly (Fig. 2, Pathway 9). Wemicke’s aphasics with severe phonological disorders may be able to spell words with an accurate meaning. When shown objects or pictures of objects, they correctly wrote the objects’ names (Heir & Mohr, 1977; Roeltgen et al., 1983). These patients were, however, unable to repeat speech, comprehend speech, or pronounce correct phonemes, findings consistent with impaired auditory word images. With the loss of auditory word images, the apparent pathway for spelling

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8

RESULTSOF OTHER COMPREHENSIONTASKS Patient 3 a. Writing homophones”

(n = 40) (Rothi, Coslett, & Heilman, 1983) (% correct) Sentence dictated

Picture shown

53

80

45

12

2

8

Correct Correctly spelled, semantically incorrect Misspelled

Patient 4 a. Comprehension of sentence: patient unable to perform task b. Spelling homophones (n = lOO)‘/(% correct) Word and Word dictated, patient shown sentence dictated uicture Correct Correctly spelled, semantically incorrect Misspelled

Word dictated, patient reads sentence and fills in the blank

35

42

44

30 35

25 33

20 36

c. Choosing homophones or pictures

Correct Incorrect Chance

Sentence dictated patient chooses from written choices

Patient shown picture and he chooses from written choices

Patient shown written homophone, he chooses picture

Homophone spelled to patient, he chooses picture

56 44 48’

51 49 48’

67 33 50

56 44 50

with accurate meaning would be directly from semantics to the lexical semantic system. Other experimental evidence also suggests this direct influence. Brown and McNeil1 (1966) showed that some normal subjects when given a definition were unable to say the correct word but were able to give some correct letters, as well as the correct position of those letters within the word. This demonstrates access to the word’s spelling without access to its phonology. This access originates from the word’s meaning (semantics in Fig. 1) and interacts directly (Fig. 2, Pathway 9) with the lexical-semantic spelling system, bypassing auditory word images. Also, a patient with a presumed left hemispheric ischemic infarction was asked to generate word lists (Morton, 1980). The patient was able to

SEMANTIC TABLE

8-Continued

Patient a. Spelling

homophones

5

(n = 100)h (% correct) Word and sentence dictated

Correct Correctly spelled, semantically incorrect Misspelled b. Comprehension

273

AGRAPHIA

Word dictated, patient shown

39 38

39 29

25

32

picture

of sentenced Semantically incorrect homophone

Comprehension of sentence demonstrated

28

25 (89%)

Note. Patients 1 and 2 not given. ” 20% of these homophones are the same as in Tables test). b A subset of the homophones in Tables 3 and 4. ’ Less than 50% because some homophonic combinations representation. d Same homophones as Tables 3 and 4.

3 and 4 (homophone

have more

spelling

than one graphemic

write correct letters in their correct positions before she was able to say the words. This finding is also best explained by postulating that the letters were generated by semantics interacting directly with the lexicalsemantic system without intervening phonology. Most of the patients presented here had some intact speech sound to letter transcoding, as demonstrated by preserved ability to spell nonwords. Since this phonological system cannot be used to spell irregular words, especially those with unique speech sound to spelling correspondence. SEMANTICS 7 AUDITORY INPUT

-

LEXICAL

AUDITORY a WORD IMAGES

SPEECH FIG.

systems, through

1.

I/’

-SEMANTIC SYS:EM

T MOTOR OUTPUT (Wrmg and oral

PHONOLOGICAL SYSTEM

A neuropsychological model for writing and spelling that stresses two parallel the lexical-semantic and phonological. Semantics interacts with these systems auditory word images (Pathway 8).

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ri”ANTjl:“\

2 LEXICAL

AUDITORY

INPUT

-

AUDITORY WORD IMAGES

I SPEECH

-SEMANTIC

3

SYSTEM

\

\e

PHON:OGICAL SYSTEM

MOTOR

OUTPUT

4/

FIG. 2. Model similar to that in Fig. 1 except that semantics interacts directly through the lexical-semantic system (Pathway 9).

our patients’ ability to correctly spell many of these irregularly spelled words demonstrates a relative preservation of the lexical-semantic spelling system (Beauvois & Derouesne, 1981; Shallice, 1981; Bub & Kertesz, 1982; Roeltgen et al., 1983; Roeltgen & Heilman, 1984). However, on the homophone spelling test all of our patients spelled irregular words that were semantically incorrect. That is, they spelled one homophone (e.g., bare) when the semantic content of the sentence indicated that an alternative spelling (e.g., bear) was the appropriate response. Some of the responses were entirely irregular with unique speech sound to spelling correspondence (e.g., stimulus: plum, response: plumb). These results demonstrate that the patients spelled irregular words that were not contextually attached to a meaning. Because irregular words are products of the nonphonological or lexical-semantic spelling system (Roeltgen et. al., 1982; Hatfield, 1982), and because the incorporation of meaning into language is a product of semantics (Heilman et al., 1976; 1981; Bub & Kertesz, 1982; Roeltgen et al., 1982; Hatfield, 1982), these results also demonstrate that what has been termed the lexical-semantic system can be dissociated from semantics. Therefore we propose that this nonphonological spelling system be termed the lexical system, reflecting its dissociability from semantics. In addition, we propose this dissociation and loss of semantic influence on writing, illustrated by these patients, be termed linguistic semantic agraphia. We use the term semantic agraphia to emphasize that aspect of the spelling system that is affected. Although some of our patients had motor disability or apraxia, the spelling disruption may best be classified a linguistic agraphia indicating a disruption within one of the mechanisms necessary for correct letter selection or word selection (Roeltgen & Heilman, 1984; Roeltgen, 1985). This designation is similar to that used for the other linguistic agraphias, phonological and lexical (Beauvois & Derouesne, 1981; Shallice, 1981; Roeltgen et al., 1983; Roeltgen & and Heilman, 1984). This disruption of a spelling system prior to motor output (for oral spelling or writing) is demonstrated by Patient 3 who demonstrated linguistic semantic agraphia in oral spelling and writing. Rather than a disruption of semantic influence, there is at least one

SEMANTIC

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AGRAPHIA

alternative explanation for at least some of the results. It is possible that the pattern of spelling (or writing) output on the homophone test was due to other factors known to be important for spelling and writing such as word class and imageability. Only two patients showed a severe word class effect on matched nouns and function words (Table 2, Patients 4 and 5). One patient (Patient 5) spelled nouns better than function words and one (Patient 4) spelled function words better than nouns. Therefore, it is possible that their production of homophones was significantly influenced by word class. However, the analysis of errors made by these patients when writing homophones (Table 7) would suggest that any influences of word class was minimal. The patient who wrote nouns better than function words made only three changes from function words to nouns and had an equal number of changes from nouns to verbs and adjectives as he had from verbs and adjectives to nouns. Patient 4, who spelled matched function words better than nouns, also had a tendency on the homophone test to change word class. However, it was in the opposite direction from what would be predicted by the word class effect seen on the results of the BLAWR (Roeltgen et al., 1982). He spelled a noun rather than a verb, adjective, or function word nine times and a verb, adjective, or function word rather than a noun four times. However, it again appeared that the number of word class changes in a particular direction would not significantly influence the results. If the lexical system is dissociable from semantics, the lexical system may function independently from semantics and the model of writing should reflect that independence (Fig. 3). This modification of the model demonstrates that the lexical system may receive independent input from both the semantic system and the area of auditory word images. Functional dissociation of lexical spelling from semantic input may be due to different functional disruptions. Analysis of the results obtained on the special comprehensions tests help address this issue. Patient 3 was better able to spell correct homophones and made less semantic errors when the semantic cue was a picture rather than a sentence. One possible explanation for this is that the patient’s auditory

-OR OUTPUl

FIG. 3. Model of writing stressing the independence of the lexical system from semantic influence (System 2). Semantics may interact with the lexical system directly (Pathway 9) or with either system (lexical or phonological) indirectly (Pathway 8).

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comprehension deficit, though very mild by the criteria of the WAB, was sufficiently severe that he was unable to comprehend the sentences. On Fig. 3 this would be represented by disrupted access of auditory input to semantics (Pathway 7) with preservation of semantics (System 10) and the input of semantics to the lexical system (Pathway 9). For Patient 4 the data are most consistent with a disruption of semantic knowledge of the homophones themselves. Under all conditions of semantic access and output that were tested, the patient was unable to demonstrate adequate use or comprehension of the homophones themselves. Such a deficit would include partial disruption of semantic processes (Fig. 3, Component 10). Alternatively, semantics might be disconnected from the input and output modalities, a disruption previously proposed to explain certain processing deficits in transcortical aphasia (Heilman et al., 1976, 1982). However, this explanation appears unlikely because the patient was able to aurally comprehend most sentences on the WAB (Kertesz, 1980), to visually comprehend words and sentences on the (RCBA) (La Pointe & Horner, 1979), and to point to pictures and words with auditory presentation of words and pictures on the WAB and RCBA, respectively. Such findings would be inconsistent with disconnections of semantics from auditory and visual input. Patient 5 demonstrated good comprehension of the sentences dictated to him, suggesting that his errors on the homophone spelling test were not due to disrupted access of auditory input to semantics (Fig. 3, Pathway 7). His equal performance on spelling homophones with auditory (sentence) or visual (picture) semantic cues suggests that his impairment was either due to a disruption of semantic competence for the homophones (as postulated for Patient 4) or disconnection of semantic output into the lexical system (Fig. 3, Pathway 9). Analysis of the special tests for semantic comprehension therefore indicate that, although all five patients showed the same general behavioral disorder (production of semantic errors on the homophone spelling test), the functional disruption differed among the three patients tested in detail. We have previously suggested that the lexical system utilizes visual word images for spelling irregular words (Roeltgen et al., 1983; Roeltgen & Heilman, 1984). Our patients spelled low-frequency and high-frequency irregular words almost equally often. This result cannot be explained on the basis of word length because both groups had the same mean length. An alternative explanation is that with impaired semantic influence, the spelling of irregular words is not wholly dependent on the frequency with which the words occur. This can be explained by postulating that the engrams of high- and low-frequency irregular words are equally stored within the system of visual word images. Without semantic influence they are accessed only by phonology (Fig. 3, Pathway I), producing any of the possible correct spellings for the given homophone group. With

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277

the addition of semantic influence, the correct engram is accessed and the correct spelling is produced. Analysis of the patients’ results for spelling orthographically regular homophones reveals patterns similar to those for irregular homophones. Again, correctly spelled but semantically incorrect responses were recorded. Also, high-frequency homophones were again spelled less often than expected and low-frequency homophones more often than expected. This similarity in response patterns between regular and irregular homophones suggests that there are similar factors influencing the production of both groups. This finding can be explained by suggesting that the regular homophones were spelled at least in part by the lexical system and not by the phonological system. This would suggest that the phonological system is used primarily when there are no available engrams within the lexical system (i.e., for nonwords and unfamiliar words) or when the lexical system is damaged. The spelling of familiar words, both regular and irregular, appears to depend primarily on the lexical system. Engrams for these words appear to be either stored within the lexical system, or alternatively, the lexical system is necessary for their retrieval. A previous study has suggested that the junction of the posterior angular gyrus and the parieto-occipital lobule is an important anatomic substrate for lexical agraphia (Roeltgen & Heilman, 1984). Therefore, this anatomic region appears important for spelling regular and irregular familiar words. Comparing the results of the regular and irregular homophones reveals that, although the patterns were similar (high-frequency homophones spelled less often than expected), a regularity effect was present, especially for high-frequency homophones. Regular homophones were spelled correctly more often than irregular homophones. The explanation for this is not certain, especially since the comparison of performances on matched regular and irregular words did not always parallel the comparisons of regular and irregular homophones. However, all patients tested were able to spell correctly many nonwords. This result suggests that some regular homophones may have been spelled correctly using the phonological spelling system, thus accounting for the better ability to spell regular homophones. A second explanation may relate to the mean length of the words in each list. The mean length of the high-frequency regular homophones was 3.5 letters, and the mean length of the high-frequency irregular homophones was 4.8 letters. It may have been easier for the patients to spell the shorter regular homophones. Although the correctly spelled but semantically incorrect homophones produced on the homophone spelling test are of primary interest, the pattern of misspellings produced by the patients is also of interest. All patients produced a moderate number of phonologically correct pseudohomophones rather than any of the real homophones. Some of these

278

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responses were orthographically complex and irregular (hygher (higher); cournel (colonel); holed, (bowled); and wruine and wrain (ruin)). Although such responses are phonologically correct, it is unlikely that they were produced by the phonological system as it is presently conceived. This system is thought to operate as an algorhythmic (letter by letter) phoneme to grapheme translation system (Roeltgen & Heilman, in press). Therefore, alternative explanations for the results obtained here are necessary. First, it is possible that the phonological system does not operate on a purely one to one basis but can generate multiple graphemes or graphemic combinations, even ones that are irregular, for a given phoneme. The data from patients with lexical agraphia (Beauvois & Derouesne, 1981; Roeltgen & Heilman, 1984) suggest this is unlikely. Those patients, especially those of Roeltgen and Heilman (1984), whose results the present authors have reviewed in detail, rarely made orthographically complex or irregular phonologically correct errors on irregular words. Most phonologically correct errors made by those patients who had disruption of the lexical system were simplified forms of the stimulus words (e.g., sovern for sovereign). Alternatively, the lexical system may not operate only on the basis of visual word images or direct, word-specific mapping of phonological input to letter output (at a word level) as implied in previous studies (Roeltgen & Heilman, 1984). These data suggest that the lexical system may utilize certain orthographic information to map phonological input onto letter output using complex or irregular phoneme to grapheme(s), syllable to graphemes, or morpheme to morpheme correspondences that are not word specific. Such a lexical system has been suggested previously (Ehri, 1980; Frith, 1980) and might be expected based on analogy with the mechanisms thought to be involved in the lexical system implicated in oral reading (Saffran, 1980). The anatomic substrate for semantic agraphia is not as precise as it is for either lexical agraphia or phonological agraphia. Although our patients had left hemispheric lesions that spared the perisylvian speech areas (Broca’s and Wemicke’s), there was little overlap among the lesions. However, the areas involved did have one common feature. They all involved areas previously associated with transcortical aphasias, including watershed distribution infarctions (Patient 1) (Geschwind, Quadfasel, & Segarra, 1968; Heilman et al., 1981), the internal capsule and the caudate (Patients 2 and 5) (Brunner, Kornhuber, Seemuller, Suger, & Wallesch, 1982; Damasio, Damasio, Rizzo, Varney, & Gersh, 1982; Naeser et al., 1982), and the thalamus (Patients 3 and 4) (McFarling, Rothi, & Heilman, 1982; Heilman, Roeltgen, Sevush, & Watson, personal observation of aphasia in a patient with thalamic infarction confirmed by autopsy). Thus, all of our patients had lesions consistent with preserved repetition and disturbed comprehension. Based on these data we therefore suggest that semantic agraphia does not have a specific anatomic locus but has relatively

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specific functional association. It appears to be associated with disturbance of comprehension seen in many transcortical aphasias. Therefore, its occurrence is associated with lesions in the anatomic substrates important for language comprehension. REFERENCES Beauvois, M. F., and Dtrouesnt, J. 1981. Lexical or orthographic agraphia. Brain, 104, 21-49. Brown, R., & McNeill, D. 1966. The “tip of the tongue” phenomenon. /our& of Verbal Learning and Verbal Behavior, 5, 326-337. Brunner, R. J., Kornhuber, H. H., Seemuller, E., Suger, G., & Wallesch, C. W. 1982. Basal ganglia participating in language pathology. Bruin and Language, 16, 281-299. Bub, K., & Kertesz, A. 1982. Deep agraphia. Brain and Language, 17, 146-165. Damasio, A. R., Damasio, H., Rizzo, M., Varney, N., & Gersh, F. 1982. Aphasia with non-hemorrhagic lesions in the basal ganglia and internal capsule. Archives ofNeurology, 39, 15-20. Ehri, L. C. 1980. The development of orthographic images. In U. Frith (Ed.), Cognitive processes in spelling. New York/London: Academic Press. Ellis, A. W. 1982. Spelling and writing (and reading and speaking). In A. W. Ellis (Ed.), Normality andpathology in Cognitive Functions. New York/London: Academic Press. Frith, U. 1980. Unexpected spelling problems. In U. Frith (Ed.). Cogniti~~e processes in spelling. New York/London: Academic Press. Geschwind, N., Quadfasel, F. A., & Segarra, J. M. 1968. Isolation of the speech area, Neuropsychologia, 6, 327-340. Hatfield. F. M. 1982. Visual and phonological factors in acquired dysgraphia. 1982. Paper presented as a poster to international Nemopsychological Society Symposium, Deauville, France. Hatfield, F. M., & Patterson, K. E. 1983. Phonological spelling. Quurter!\. Jorrrnul of‘ Experimental Psychology, 35, 451-468. Heilman, K. M., Rothi, L., McFarling, D.. & Rottmann, A. L. 1981. Transcortical sensory aphasia with relatively spared spontaneous speech and naming. Archives ofNrwo/ogy. 38, 236-239. Heilman, K. M., Tucker, D. M.. & Valenstein. E. 1976. A case of mixed transcortical aphasia with intact naming. Bruin, 99, 415-426. Heir. D. B., & Mohr. J. P. 1977. Incongruous oral and written naming. Bruin trnd Lung~~gr. 4, 115-126. Kertesz, A. 1980. Western Aphasia Battery. London, Ontario: University of Western Ontario. La Pointe, L. L., & Horner. J. 1979. Reading Comprehension Battery for Aphasia. Tigard. OR: C. C. Publications. McFarling, D., Rothi, L., & Heilman, K. M. 1982. Transcortical aphasia from ischaemic infarcts of the thalamus: A report of two cases. Jo~mtrl of Neurology, Neurosro’get? und Psychiutry, 45, 107-l 12. Morton, J. 1980. The logogen model and orthographic structure. In U. Frith (Ed.), Cognitir,e processes in spelling. New York/London: Academic Press. Naeser. M. A., Alexander, M. P., Helm-Estabrooks, N., Levine. H. L., Laughlin, S. A., & Geschwind, N. 1982. Aphasia with predominantly subcortical lesion sites. Archi\,es qf Neurology, 39, 31-14. Roeltgen, D. P. 1985. Agraphia. In K. M. Heilman & E. Valenstein (Eds.), Clinicul Neuropsychology. New York: Oxford Univ. Press. 2nd. ed. Roeltgen, D. P., Cordell, C., & Sevush. S. 1983. A battery of linguistic analysis for writing and reading. Internutionul Neltropsyc~hologiccrl So<,iaty Bulletin. October 3 I,

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Roeltgen, D. P., & Heilman, K. M. 1984. Lexical agraphia, further support for the twosystem hypothesis of linguistic agraphia. Brain, 107, 811-827. Roeltgen, D. P., & Heilman, K. M. In press. Review of agraphia and a proposal for an anatomically based neuropsychological model of writing. Applied Psycholinguistics. Roeltgen, D. P., Sevush, S., & Heilman, K. M. 1983. Phonological agraphia, writing by the lexical-semantic route. Neurology, 33, 755-765. Rothi, L. J., Coslett, H. B., & Heilman, K. M. 1983. Battery of Adult Reading Function. Experimental ed. Saffran, E. M. 1980. Reading in deep dyslexia is not ideographic. Neuropsychologia, 18, 219-223. Shallice, T. 1981. Phonological agraphia and the lexical route in writing. Brain, 104, 412429. Stengel, E. 1947. A clinical and psychological study of echoreactions. Journal ofMenra/ Science, 93, 598-612. Thorndike, E. L., & Lorge, I. 1944. The teacher’s word book of 30,000 words. New York: Teachers College Press. Whitaker, H. 1976. A case of isolation of the language function. In H. Whitaker & H. A. Whitaker (Eds.), Studies in neurolinguisrics. New York: Academic Press.