Specialization Depend on Literacy Brain
for
Language Does Not
Ant\l=o'\nioR. Damasio, MD, PhD; A. Castro-Caldas, MD; Jorge T. Grosso, MD; Jos\l=e'\M. Ferro
\s=b\
Aphasia in focal brain-damaged illitanalogous to aphasia in patients
erates is
who have learned how to read and write, regarding (1) expectancy rate, (2) distribution of clinical types, (3) semiological structure, and (4) score of relevant laboratory variables. The organization of neurological structures whose lesions produce language disturbances seems to be independent from the acquisition of reading and writing skills. (Arch Neurol 33:300-301, 1976)
is
potent literacy The development neurophysiological specificity idea that factor in the
guage has been supported claim that illiterates rarely
a
of for lan¬ by the become
aphasie, or that their aphasias are mild, clinically atypical, and do not appear in correspondence to the loci of lesions usually related to aphasie syndromes.1'1 Since many of the early discoveries of aphasia were made in
illiterates, such contentions appear unlikely. However, to this day there has been no controlled investigation on the matter that uses modern tools of neuropsychology.3 Data reported in
Accepted for publication Dec 20, 1974. From the Language Research Laboratory, Centro de Estudos Egas Moniz, Lisbon Faculty of Medicine, Portugal. Dr Damasio is now with the Department of Neurology, University of Iowa Hospitals, Iowa City. Reprint requests to Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242 (Dr Dam\l=a'\ssio).
this article prove that illiterate, brain¬ damaged adults may be expected to develop the proportion and types of aphasia of literate patients, and that their aphasie syndromes are analo¬ gous regarding clinical and laboratory measures.
SUBJECTS AND METHODS A random series of 247 adult, focal brain¬
damaged patients was studied in standard conditions. Thirty-eight patients were illit¬ erate, being unschooled and totally unable to read and to write prior to disease. The patients were divided into two groups, according to hemispheral side of lesion. Aphasies were identified by stan¬ dardized tests." Included in the study were the following: 1. Quantitative and qualitative analysis of speech, produced in response to a set of standard questions (measuring of frequen¬ of words, detection of lexic inadequacies, and detection of errors in
Handedness was evaluated on the basis a standard questionnaire. The patients were classified as (1) nonaphasic, (2) fluent aphasie, or (3) nonfluent aphasie. The latter group was subdivided into (o) Broca aphasia and (b) global apha¬ sia. Side of lesion, results of the aphasia examination, and handedness were corre¬ lated with sex, age, social background, general clinical picture, and nature and localization of lesion. Since the token test provides a particu¬ larly effective measure of aphasie symp¬ toms, a comparison study of its perform¬ ance was carried out with literate, brain¬ damaged control patients matched for sex, age, cause of lesion, location of lesion, and type of aphasia. The percentages of aphasie and nonaphasic cases in the whole cohort of illiter¬ ates were compared with the correspond¬ ing percentages in the group of literate, of
brain-damaged patients.
RESULTS
cy rate
syntactic structure)
2. Evaluation of verbal comprehension studied with (a) a test for comprehension of simple verbal commands, (6) a test of visual multiple-choice responses to verbal utterances, and (c) a shortened, validated version of the token test7 (maximum score, 22; cutoff point, 20) 3. Evaluation of the ability to repeat words, digits, and phrases of different length and different syntactic structure 4. Evaluation of the ability to name objects and pictures in the visual and tactile modalities 5. Evaluation of constructional ability and presence of parietal signs.
Downloaded From: http://archneur.jamanetwork.com/ by a New York University User on 06/01/2015
Of 38 illiterate patients, 24 had focal lesions of the left hemisphere and 14 had focal lesions of the right hemi¬
sphere.
Of the 38 brain-damaged, illiterate patients, 12 were aphasie. The 21 patients included 13 men and eight women who ranged in age from 35 to 75 years, with a mean age of 58. They all had a rural social background. The cause of their brain damage was believed to be vascular in 19 patients, and neoplastic in two. Twenty of the 21 aphasie patients suffered from left hemispheral damage, and all were
Token Test Scores*
Type of
Aphasia Fluent
Illiterates
Control
(N
(N
=
20)
=
20)
Range Mean
5-11
Mean 6.5
5-10.5
6.4
9-20.5 5-9
15.2 6.0
6.5-20 5-8
14.4 6.3
Range
tients became aphasie (55.2%) and 114 of the 209 literate patients became aphasie (54.2%). Thus, there was no appreciable difference between the two groups.
COMMENT
Nonfluent Broca Global *
Literate brain-damaged patients matched for age, sex, type of aphasia, and localization of lesion.
right-handed. Six of these patients had fluent aphasia, ten had Broca aphasia, and four had global aphasia. The one aphasie patient suffering from right-hemispheral damage was left-handed and had a fluent apha¬ sia.
Twenty control patients matched for age, sex, type of aphasia, and localization of the lesion were com¬ pared with the right-handed, lefthemisphere-lesioned, illiterate pa¬ tients. The data summarized in the Table indicate no appreciable differ¬ ence in the results of the token test between the two groups. In the total 247 brain-damaged patients, there were 135 aphasies. Twenty-one of the 38 illiterate pa-
Focal lesions of the left
hemisphere illiterate, right-handed individuals produced aphasie syndromes of the same type and proportion found in a series of literate, brain-damaged pa¬ tients. The results militate against the in
traditional notions that illiterates do not develop clear-cut dominance for language, or that their dysphasic
signs
equally probable following right-hemisphere lesions. findings suggest that the neu¬ rological structures whose lesions de¬ termine aphasia are the same for literate or illiterate patients, and that the development and final arrange¬ leftThese
are or
ment of these structures does not
depend on the acquisition of reading and writing skills. This is consonant with the idea of "prelearning" neurophysiological specificity related to language, which has been lately sup¬ ported by findings from several
branches of the neurosciences. This
Geschwind and Levitsky" have demon¬ strated the asymmetry of the left planum temporale, which has been shown to be already present in the fetus," and Le May and Culebras1" have called attention to the angio¬ graphie asymmetry of Sylvian points, evidence of markedly different volumes of parietal opercula. Further¬ more, all these results have been related to handedness, and it is apparent that left-handed persons do not show the same type of asymme¬ tries.9" The finding of a dominance effect in the pattern of dichotic listening of children just under school age is in keeping with this concept,'-13 and, probably, so is the fact that ambi¬ dextrous children show signs of lan¬
performance difficulties, ie, dyslexia, more often than children guage
with well-established cerebral domi¬ nance do.14 Adequate acquisition of literacy requires a differentiated higher nervous system—in other words, a brain with dominance. Con¬ versely, it seems improbable that such phylogenetically recent abilities as reading and writing influence neurophysiological organization to any ex¬ tent.
References 1. Weber E, cited by Critchley M: Speech and speech-loss in relation to the duality of the brain, in Mountcastle VB (ed): Interhemispheric Rela-
tions and Cerebral Dominance. Baltimore, Johns Hopkins Press, 1962, p 208. 2. Critchley M: Premorbid literacy, and the pattern of subsequent aphasia. Proc Soc Med 49:335-336, 1956. 3. Eisenson J, in discussion, DeReuck AVS, O'Connor M (eds): Disorders of Language. London, J&A Churchill Ltd, 1964, p 259. 4. Cameron RF, Currier RD, Haerer AF: Aphasia and literacy. Br J Disord Commun 6:161-163, 1971. 5. Critchley M: Inter-hemispheric partnership and inter-hemispheric rivalry, in Critchley M
(ed): Scientific Foundations of Neurology. London, William Heineman Ltd, 1973, p 219.
6. Dam\l=a'\sioAR: Neurologia da Linguagem. Lisbon, Livraria Buchholz, 1973. 7. De Renzi E, Vignolo L: The token test: A sensitive test to detect receptive disturbances in aphasics. Brain 85:665-678, 1962. 8. Geschwind N, Levitsky W: Human brain: Left-right asymmetries in temporal speech region. Science 161:186-187, 1968. 9. Teszner D, Tzavaras A, Gruner J, et al: L'asym\l=e'\triedroite-gauche du planum temporale: \l=A`\propos de P\l=e'\tudeanatomique de 100 cerveaux. Rev Neurol 126:444-448, 1972. 10. Le May M, Culebras A: Human brain: Morphologic differences in the hemispheres
Downloaded From: http://archneur.jamanetwork.com/ by a New York University User on 06/01/2015
demonstrable by carotid arteriography. N Engl J Med 287:168-170, 1972. 11. Geschwind N: Cerebral dominance and anatomic asymmetry. N Engl J Med 287:194-195, 1972. 12. Kimura D: Functional asymmetry of the brain in dichotic listening. Cortex 3:163-178, 1967. 13. Geffner DS, Hochberg I: Ear laterality performance of children from low and middle socioeconomic levels on a verbal dichoting listening task. Cortex 7:193-203, 1971. 14. Vernon MD: Reading and its Difficulties. London, Cambridge University Press, 1971.
for
Language Does Not
Ant\l=o'\nioR. Damasio, MD, PhD; A. Castro-Caldas, MD; Jorge T. Grosso, MD; Jos\l=e'\M. Ferro
\s=b\
Aphasia in focal brain-damaged illitanalogous to aphasia in patients
erates is
who have learned how to read and write, regarding (1) expectancy rate, (2) distribution of clinical types, (3) semiological structure, and (4) score of relevant laboratory variables. The organization of neurological structures whose lesions produce language disturbances seems to be independent from the acquisition of reading and writing skills. (Arch Neurol 33:300-301, 1976)
is
potent literacy The development neurophysiological specificity idea that factor in the
guage has been supported claim that illiterates rarely
a
of for lan¬ by the become
aphasie, or that their aphasias are mild, clinically atypical, and do not appear in correspondence to the loci of lesions usually related to aphasie syndromes.1'1 Since many of the early discoveries of aphasia were made in
illiterates, such contentions appear unlikely. However, to this day there has been no controlled investigation on the matter that uses modern tools of neuropsychology.3 Data reported in
Accepted for publication Dec 20, 1974. From the Language Research Laboratory, Centro de Estudos Egas Moniz, Lisbon Faculty of Medicine, Portugal. Dr Damasio is now with the Department of Neurology, University of Iowa Hospitals, Iowa City. Reprint requests to Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242 (Dr Dam\l=a'\ssio).
this article prove that illiterate, brain¬ damaged adults may be expected to develop the proportion and types of aphasia of literate patients, and that their aphasie syndromes are analo¬ gous regarding clinical and laboratory measures.
SUBJECTS AND METHODS A random series of 247 adult, focal brain¬
damaged patients was studied in standard conditions. Thirty-eight patients were illit¬ erate, being unschooled and totally unable to read and to write prior to disease. The patients were divided into two groups, according to hemispheral side of lesion. Aphasies were identified by stan¬ dardized tests." Included in the study were the following: 1. Quantitative and qualitative analysis of speech, produced in response to a set of standard questions (measuring of frequen¬ of words, detection of lexic inadequacies, and detection of errors in
Handedness was evaluated on the basis a standard questionnaire. The patients were classified as (1) nonaphasic, (2) fluent aphasie, or (3) nonfluent aphasie. The latter group was subdivided into (o) Broca aphasia and (b) global apha¬ sia. Side of lesion, results of the aphasia examination, and handedness were corre¬ lated with sex, age, social background, general clinical picture, and nature and localization of lesion. Since the token test provides a particu¬ larly effective measure of aphasie symp¬ toms, a comparison study of its perform¬ ance was carried out with literate, brain¬ damaged control patients matched for sex, age, cause of lesion, location of lesion, and type of aphasia. The percentages of aphasie and nonaphasic cases in the whole cohort of illiter¬ ates were compared with the correspond¬ ing percentages in the group of literate, of
brain-damaged patients.
RESULTS
cy rate
syntactic structure)
2. Evaluation of verbal comprehension studied with (a) a test for comprehension of simple verbal commands, (6) a test of visual multiple-choice responses to verbal utterances, and (c) a shortened, validated version of the token test7 (maximum score, 22; cutoff point, 20) 3. Evaluation of the ability to repeat words, digits, and phrases of different length and different syntactic structure 4. Evaluation of the ability to name objects and pictures in the visual and tactile modalities 5. Evaluation of constructional ability and presence of parietal signs.
Downloaded From: http://archneur.jamanetwork.com/ by a New York University User on 06/01/2015
Of 38 illiterate patients, 24 had focal lesions of the left hemisphere and 14 had focal lesions of the right hemi¬
sphere.
Of the 38 brain-damaged, illiterate patients, 12 were aphasie. The 21 patients included 13 men and eight women who ranged in age from 35 to 75 years, with a mean age of 58. They all had a rural social background. The cause of their brain damage was believed to be vascular in 19 patients, and neoplastic in two. Twenty of the 21 aphasie patients suffered from left hemispheral damage, and all were
Token Test Scores*
Type of
Aphasia Fluent
Illiterates
Control
(N
(N
=
20)
=
20)
Range Mean
5-11
Mean 6.5
5-10.5
6.4
9-20.5 5-9
15.2 6.0
6.5-20 5-8
14.4 6.3
Range
tients became aphasie (55.2%) and 114 of the 209 literate patients became aphasie (54.2%). Thus, there was no appreciable difference between the two groups.
COMMENT
Nonfluent Broca Global *
Literate brain-damaged patients matched for age, sex, type of aphasia, and localization of lesion.
right-handed. Six of these patients had fluent aphasia, ten had Broca aphasia, and four had global aphasia. The one aphasie patient suffering from right-hemispheral damage was left-handed and had a fluent apha¬ sia.
Twenty control patients matched for age, sex, type of aphasia, and localization of the lesion were com¬ pared with the right-handed, lefthemisphere-lesioned, illiterate pa¬ tients. The data summarized in the Table indicate no appreciable differ¬ ence in the results of the token test between the two groups. In the total 247 brain-damaged patients, there were 135 aphasies. Twenty-one of the 38 illiterate pa-
Focal lesions of the left
hemisphere illiterate, right-handed individuals produced aphasie syndromes of the same type and proportion found in a series of literate, brain-damaged pa¬ tients. The results militate against the in
traditional notions that illiterates do not develop clear-cut dominance for language, or that their dysphasic
signs
equally probable following right-hemisphere lesions. findings suggest that the neu¬ rological structures whose lesions de¬ termine aphasia are the same for literate or illiterate patients, and that the development and final arrange¬ leftThese
are or
ment of these structures does not
depend on the acquisition of reading and writing skills. This is consonant with the idea of "prelearning" neurophysiological specificity related to language, which has been lately sup¬ ported by findings from several
branches of the neurosciences. This
Geschwind and Levitsky" have demon¬ strated the asymmetry of the left planum temporale, which has been shown to be already present in the fetus," and Le May and Culebras1" have called attention to the angio¬ graphie asymmetry of Sylvian points, evidence of markedly different volumes of parietal opercula. Further¬ more, all these results have been related to handedness, and it is apparent that left-handed persons do not show the same type of asymme¬ tries.9" The finding of a dominance effect in the pattern of dichotic listening of children just under school age is in keeping with this concept,'-13 and, probably, so is the fact that ambi¬ dextrous children show signs of lan¬
performance difficulties, ie, dyslexia, more often than children guage
with well-established cerebral domi¬ nance do.14 Adequate acquisition of literacy requires a differentiated higher nervous system—in other words, a brain with dominance. Con¬ versely, it seems improbable that such phylogenetically recent abilities as reading and writing influence neurophysiological organization to any ex¬ tent.
References 1. Weber E, cited by Critchley M: Speech and speech-loss in relation to the duality of the brain, in Mountcastle VB (ed): Interhemispheric Rela-
tions and Cerebral Dominance. Baltimore, Johns Hopkins Press, 1962, p 208. 2. Critchley M: Premorbid literacy, and the pattern of subsequent aphasia. Proc Soc Med 49:335-336, 1956. 3. Eisenson J, in discussion, DeReuck AVS, O'Connor M (eds): Disorders of Language. London, J&A Churchill Ltd, 1964, p 259. 4. Cameron RF, Currier RD, Haerer AF: Aphasia and literacy. Br J Disord Commun 6:161-163, 1971. 5. Critchley M: Inter-hemispheric partnership and inter-hemispheric rivalry, in Critchley M
(ed): Scientific Foundations of Neurology. London, William Heineman Ltd, 1973, p 219.
6. Dam\l=a'\sioAR: Neurologia da Linguagem. Lisbon, Livraria Buchholz, 1973. 7. De Renzi E, Vignolo L: The token test: A sensitive test to detect receptive disturbances in aphasics. Brain 85:665-678, 1962. 8. Geschwind N, Levitsky W: Human brain: Left-right asymmetries in temporal speech region. Science 161:186-187, 1968. 9. Teszner D, Tzavaras A, Gruner J, et al: L'asym\l=e'\triedroite-gauche du planum temporale: \l=A`\propos de P\l=e'\tudeanatomique de 100 cerveaux. Rev Neurol 126:444-448, 1972. 10. Le May M, Culebras A: Human brain: Morphologic differences in the hemispheres
Downloaded From: http://archneur.jamanetwork.com/ by a New York University User on 06/01/2015
demonstrable by carotid arteriography. N Engl J Med 287:168-170, 1972. 11. Geschwind N: Cerebral dominance and anatomic asymmetry. N Engl J Med 287:194-195, 1972. 12. Kimura D: Functional asymmetry of the brain in dichotic listening. Cortex 3:163-178, 1967. 13. Geffner DS, Hochberg I: Ear laterality performance of children from low and middle socioeconomic levels on a verbal dichoting listening task. Cortex 7:193-203, 1971. 14. Vernon MD: Reading and its Difficulties. London, Cambridge University Press, 1971.
