JOURNAL
OF COMMUNICATION
MSORDERS
12 t 1979), 2 11- 2 16
211
CORTICAL WORD
E
BERNARD T. TERVQORT* UniversiQ
and BERNARD ofAmsterdam
J. ANSINK
-_
- -__ --
-..._--__.
Despite the recent report of Goldstein et al. (1975) on pure word deafness in an adult. it still seems worthwhile to study the case of corfical deafness in a child, not only because we believe this to be one of the very few cases duly reported upon, but also because of its interesting pathological history, its implications for the existence of specific speech sound detectors, and its evidence of pathological communicative behavior which deviates from that of a deaf child. ~-___
--
----
_-____ -
______
Introduction
After its first description by Liepmann ( 1898), auditory agnosia was considered a distinct phenomenon, as we know from Henschen ( 1920- 1922). Kleist ( 1934), and Feuchtwangler ( 1930); Nadoleczny ( 1926) was the first to use the term ‘ ‘psychic deafness ’ ’ half a century ago. He described it as a defect in the association between auditive perception and comprehension, and suggested different pathways in the processing of verbal vs nonverbal sound stimuli. Pathological findings, like those of Eoebell (1967‘ tienschen (1920- 1922), Hecaen ( 1973), and Arnold ( 1960) 9 supplied exact escriptions of this cortical or subcortical deafness in adults as a form of agnosia bordering on aphasia. WorsterDrought (1965) proposed four specific types of auditive agnosia: ( 1) pure word deafness, (2) word deafness with agnosia for nonverbal xunds, (3) word deafness with visual agnosia, and (4) no reactions to sound except those evoked during sleep in the EEG. Our report concerns the first type, as described by Goldstein et al., ( 1975). They term the occurrence of pure word deafness in adults as “an infrequently nc:ed symptom. ” WC believe our case to be one of the few studies made of a child’s cortical word deafness-albeit complicated by other factors-and therefore significant by virtue of the additional information it gives.
*Address correspondence to: Dr. Bernard T. Tervoort, Institute of General Linguistics, Spuistraat 2 10, Amsterdam, The Netherlands.
@Elsevier North Holland, Inc., 1979
002 l-9924/79/032 1I -06$0 1.75
BERNARD T. TERVOORT
212
and BERNARD J. ANSINK
The Case Johan E., born in 1960, was referred to our interdisciplinary research group on child language pathology in 1974. The case history leaves many questions unanswered regarding pregnancy, birth, and early development. The little that is known about the case history, together with the results of the tests, however, warrant the diagnosis of cortical deafness. It should be added that a complication presented itself at the time the diagnosis was made, i.e., that the boy had previously suffered from kemicterus. During her 7th pregnancy Johan’s mother had to undergo surgery for thyroid dysfunction; the specific kind of dysfunction was not described in her medical history. Ibe delivery began spontaneously after an amenorrhea of about 40 wk, but was c ymplicated by a period nearly devoid of uterine contractions for which pitrescine was given (intramuscular). The total duration of the delivery was 62 r. The child’s birth weight was 3200 g. At birth the boy suffered from pronounced jaundice and was very cyanotic. This was followed by serious respiratory trouble. After 2 days, hyperbilirubinemia made blood transfusions necessary. Consequently, both Johan’s motor development and his emotional growth were severely retarded. During early childhood his sleep pattern was irregular. Although his mother claims that he vocalized and babbled in the prelinguistic period, he never arrived at spontaneous speech, not even at the holophrastic level At the age 2 yr a hearing loss was suspected, but his audiogram turned out to be normal and it remained that way in 1966, 1968, and 1970. Then in 1973 a flat tossof 80 dB was registered in both ears. At the age 4 yr, his first psychological test 0MSC) resulted in an IQ of 35 which did not increase noticeably in the following years, although in 1973 he scored at a level of 75. At age 13 yr his communication c’ifficulties had created so many problems with his environment that he was referred to the University of Amsterdam group. Examination
We found Johan to be a boy of normal posture with retarded motor functions but without signs of ataxia or of vestibular dysfunction. He did display a slight choreatetosis with hyperextension of hand and finger articulations. The plantar exes were of the Babinski type. The tendon reflexes of the upper and lower extremities were exaggerated, more on the left than on the right. EEG results were clearest with pharynx electrodes: they showed a focus of sharp waves at isting of two psychologists, two psycholinguists, and two special educators, one neurologist, hther I, and a physiotherapist, all of whom have contributed to the information given
CORTICAL WORD DEAFNESS: A CASE HISTORY
213
both temporal levels. Clinical and EEG information .qs well as the boy’s total communicative behavior (cf. below) pointed to a bilateml temporal lesion causing pure cortical word deafness, i.e., a selective agnosia for speech perception. He showed, moreover, signs of a nuclear cochlear deafness, perhaps as a consequence of kemicterus. Psychological testing by team members (WISC, Bender et al .) revealed a fairly normal intelligence as long as language comprehension was not involved or speech responses were not required. Typical of this is the fact tiiat the boy’s performance in tasks such as picture completion or arrangement ranged from normal to good. Pure tone perception was possible with the help of his hearing aid at threshold level to the extent that half-tone differences were distinguished. Identification by ear of different sounds (like coins rattling in a cup, a small bell ringing, finger tapping, the rattling of keys, toy instruments) revealed normal sound gnosis. The boy paid attention to indistinct human sounds like a cry or t.houting, but he gave no spontaneous attention to spoken language. It was possible to start communication with him, but this had to be done by waving at him, catching his eye, or by making signs when he was looking.
Communication While communicating, Johan watched his partner’s total behavior, hands and lips, usually in that order. In other words, he received most of his information from pantomimic expression, from (deaf) signs (if the partner knew any, which Tervoort did), and finally from lip reading. As stated, he got nothing from listening. His own production showed the same hierarchy. He imitated most of what he wanted to convey, used some deaf signs, and, on and off, added some nearly indistinct oral movements with vocalizations. That way, most of what he tried to utter was completely lost to outsidp tind remained hard to understand even for those close to him. By the same oken, what he got out of a partner’s attempts to reach him with language were haphazard single clues out of a series of trials and misunderstandings. His knowledge of the deaf signs was very slight; he did not use them in the usual abbreviated, conventionalized form but merely iconically, as imitations; moreover, he was not able to use them in sequences comparable with spoken utterances having syntactic cohesion. His most successful way of conversing was enthusiastic acting or reenacting. Once triggered by a “key” word, he would start such an act. It appeared, to be easier to trigger him through the written than through the spoken word. One example was the written letterword “TV” (normally used in Dutch for “television”) which triggered the reenacting of complete programs of Johan’s liking, mostly with a lot of fighting. shooting, and other violent excitement. A more detailed description of one OT the rare occasions on which Johan volunteered information, thus initiating a context himself, can give a fuk-
214
BERNARD T. TERVOOR?
and BERNARD
J. ANSINK
impression of the inefficiency of his communication attempts. He waved at his ner (Tervmrt), then waved aside (which meant “far, far away,” as became later) and made the sign of holding the wheel of a car ( “far away” plus “where we came from by car this morning ’ ‘) while uttering the nds Iwibibawal, but far less precisely than the notation would suggest; it cmld equally well be noted /bibipala/, /wewewa/, /piipiimala/ and all the permutatticmsthereof. As Tervoort kept making the sign for “What?” Johan added the itative sign for “baby. ” This solved the first part of his utterance insofar as it clear that he was talking about a baby far away from where he had come car. When Tervoort made the signs for “baby ” plus “yours, ” Johan vigorously, so that it could be assumed that he wanted to say something t his baby brother at home; an assumption that proved to be correct but that supposed more background or inside knowledge than a new partner usually Later information revealed that the first “word” used by Johan here was not 2, however, as was first concluded, but in all probability /wibi/, which was name of his little brother. The second “word” remained incomprehensible Jahan could not find its :+igncounterpart, until Tervoort-after several guesses---came up with the right one, which was the sign for talking or ng, Dutch /prata/. It was not until then that it was noticed that Johan was making the sign and simultaneously shaking his head, while repeating his said” was not “baby talk,‘* but: “baby not talk,” translataa~: my little brother Wibi can’t talk yet. This whole stretch of conversation well over a minute. ban’s reading competence was below that of a second grader. When asked to a very simple story at that level, he uttered sounds that could not be nized as pertaining to the words. We would deal with each word apart, either with the happy “aha” reaction of or with a shrugging of his shoulders and a face showing “gosh, we have now?“’ nalyzing words into graphemes was impossible, as was reading even a short ce as a unit of a higher order. The few words he could read were recog-
y feasible to ascribe Johan’s difficulties to his cochleonuclear deafcame about at a later age as indicated by the early normal audiog, the verbal agnosia must be considered to be the cause. The hearing n exhibited at the age of 13 yr must have developed since the time *his i audiogram had been produced, in 1970. Nuclear deafness may dein the early and middle teens in children that have been suffering from jaundice: the kemicterus is not by a long way completed in ear~:ychild-
CORTICAL WORD DEAFNESS A CASE HISTORY
215
The cause of his verbal agnosia should be sought in perinatal pathology, in which the temporal lobes can be very vulnerable. Apparently, his communicative behavior at the (pseudo)imbecil level stems exclusively from the almost complete blocking of his language development from the very onset. This is shown at the (verbal) sign level as well as at the syntactic level. His symbolic awareness has not ;et reached the developmental stage of generalization and socialization, although there is some insight into the basic functioning of a sign. insofar as he uses deaf signs and knows some words. Signing for him is easier than using words. In this respect this case is not different from other types of handicaps (Brown, 1977). A further analysis of. this visual communication would in all probability show the presence of basic grammatical relations, like the ones found by Feldman et al. ( 1977). Johan can bring two or three notions together in words, sometimes in a mere associative succession (“far away” + “car”), sometimes as an interdependence of some kind ( “baby” + “talk” + “not “). Thus the boy differs greatly from an ordinary deaf child. The latter can be reached through vision (if not also by residual hearing and vibratory and kinesthetic perception) and so is given full opportunity to arrive at a satisfactory verbal and language level during his school years. The best proof of this difference is that the school for the deaf which Johan attended has given him so little. At his age of 14 yr, the prognosis for further communicative and educational development is poor. Educationally, there was no better opportunity available, which is different from saying that it would have been impossible to create one, e.g., within the context of individual care for multiple-handicapped hearing-impaired children. Permanent institr ,onalization of a boy like Johan is too unsatisfactory a solution in present da! society. Another conclusion that emerges from this case history that might be of certam theoretical and more general value, is the fact that the reality of specific speech sound feature detectors-as described, e.g.. by Eimas and Corbit (1973)---is corroborated. The occurrence of cases of developmental pure verbal auditory agnosia amounts to clinical evidence for such a specific speech analysis system- the point being that there was no audiogl.am deafness up to 19’73 although word deafnessappears to have been present from birth. Finally, there is one last point which this case reintroduces. Developmental neurology shows some fundamental differences from general neurology concerning adults. ‘The point of departure of the latter is normal anatomical and functional development of the nervous system, from conception to full maturity; this is quite obviously not so in the case of the former. There are structural differences. However, neither developmental neurology, nor psycholinguistics, nor any other field of specialty dealing with complicated cases like this could by itself meet the challenge; the multidisciplinary approach, then, is the only possibility.
216
BERNARD T. TERVOORT and BERNARD J. ANSINK
Arnold, b. (1960). Angeborene worttaubheit. Zeitschrift fir Laryngologie und Rhinologie 39: 5259. Brown, R. (1977). Why are signed languages easier to learn than spoken languages? Keynote Address to the National Association of the Deaf. Chicago, May 3 l-June 4. Eimas, PD., and Corbit, J.D. (1973). Selective adaptation of linguistic feature detectors. Cognitive Psychof. 4: 99- 110. Feldman, H., Goldin-Meadow, S. and Gleitman, L. (1977). The creation of language by linguistically deprived children. In Action, Gesture and Symbol: The Emergence of Language. New York: Academic. Feuchtwangler, E. ( 1930). Amusia: Studien zur pathologischen Psychologie der Akustischen Wahmehmung. Monographs aus den Gesamtgebiete der Neurologie und Psychologie. Berlin: Springer-Verlag. Goldstein. M. N. (1974). Auditory agnosia for speech (“pure word deafness”). Brain and Lang. 1: 195-204. Geldstein. M. N., Brown, M., and Hollander, J. (1975). Auditory agnosia and cortical deafness: analysis of a case with three-year follow-up. Brain and Lang. 2: 324-332. Hkcaen, H. ( 1973). Introduction a la neuropsychologie. Paris. Larousse. Hm=hen, S.E. ( 1920- 1922). Klinische und Anatomische Beitriige zur Pathologie des Gehirns. Stockholm. Kteist. K. (1934). Gehirn Pathologic. Leipzig: Barth. Kkisf . K . ( 1%2). Sensory Aphasia and Amusia. Oxford: Pergamon . kpmann, H. ( 1898). Ein Fall von reiner Sprachtaubheit. Psychiatrische Abhandlungen, Breslau. bell, E. (1967). Zur Diagnose und Therapie bei Seelentaubheit. Sprachheilpadagogische und Himpathologische Probleme bei der Rehabilitation von Him- und Sprachgeschkiigten: Hamburg. leemy, M. ( 1926). Lehrbuch der Sprach- und Stimmheilkunde. Leipzig: Vogel, pp. 4 I-48. Wrster-Drought . :, . , and Allen, I.M. (1929, 1920). Congenital auditory imperception. J. Neural. andPsychopath. 9: 289, i0, 193. Wooster-Drought, C. ( 1965). Observations on congenital auditory imperception. Acta Therupeutica Vocahca et Logopedica. 1: 65 - 67.
OF COMMUNICATION
MSORDERS
12 t 1979), 2 11- 2 16
211
CORTICAL WORD
E
BERNARD T. TERVQORT* UniversiQ
and BERNARD ofAmsterdam
J. ANSINK
-_
- -__ --
-..._--__.
Despite the recent report of Goldstein et al. (1975) on pure word deafness in an adult. it still seems worthwhile to study the case of corfical deafness in a child, not only because we believe this to be one of the very few cases duly reported upon, but also because of its interesting pathological history, its implications for the existence of specific speech sound detectors, and its evidence of pathological communicative behavior which deviates from that of a deaf child. ~-___
--
----
_-____ -
______
Introduction
After its first description by Liepmann ( 1898), auditory agnosia was considered a distinct phenomenon, as we know from Henschen ( 1920- 1922). Kleist ( 1934), and Feuchtwangler ( 1930); Nadoleczny ( 1926) was the first to use the term ‘ ‘psychic deafness ’ ’ half a century ago. He described it as a defect in the association between auditive perception and comprehension, and suggested different pathways in the processing of verbal vs nonverbal sound stimuli. Pathological findings, like those of Eoebell (1967‘ tienschen (1920- 1922), Hecaen ( 1973), and Arnold ( 1960) 9 supplied exact escriptions of this cortical or subcortical deafness in adults as a form of agnosia bordering on aphasia. WorsterDrought (1965) proposed four specific types of auditive agnosia: ( 1) pure word deafness, (2) word deafness with agnosia for nonverbal xunds, (3) word deafness with visual agnosia, and (4) no reactions to sound except those evoked during sleep in the EEG. Our report concerns the first type, as described by Goldstein et al., ( 1975). They term the occurrence of pure word deafness in adults as “an infrequently nc:ed symptom. ” WC believe our case to be one of the few studies made of a child’s cortical word deafness-albeit complicated by other factors-and therefore significant by virtue of the additional information it gives.
*Address correspondence to: Dr. Bernard T. Tervoort, Institute of General Linguistics, Spuistraat 2 10, Amsterdam, The Netherlands.
@Elsevier North Holland, Inc., 1979
002 l-9924/79/032 1I -06$0 1.75
BERNARD T. TERVOORT
212
and BERNARD J. ANSINK
The Case Johan E., born in 1960, was referred to our interdisciplinary research group on child language pathology in 1974. The case history leaves many questions unanswered regarding pregnancy, birth, and early development. The little that is known about the case history, together with the results of the tests, however, warrant the diagnosis of cortical deafness. It should be added that a complication presented itself at the time the diagnosis was made, i.e., that the boy had previously suffered from kemicterus. During her 7th pregnancy Johan’s mother had to undergo surgery for thyroid dysfunction; the specific kind of dysfunction was not described in her medical history. Ibe delivery began spontaneously after an amenorrhea of about 40 wk, but was c ymplicated by a period nearly devoid of uterine contractions for which pitrescine was given (intramuscular). The total duration of the delivery was 62 r. The child’s birth weight was 3200 g. At birth the boy suffered from pronounced jaundice and was very cyanotic. This was followed by serious respiratory trouble. After 2 days, hyperbilirubinemia made blood transfusions necessary. Consequently, both Johan’s motor development and his emotional growth were severely retarded. During early childhood his sleep pattern was irregular. Although his mother claims that he vocalized and babbled in the prelinguistic period, he never arrived at spontaneous speech, not even at the holophrastic level At the age 2 yr a hearing loss was suspected, but his audiogram turned out to be normal and it remained that way in 1966, 1968, and 1970. Then in 1973 a flat tossof 80 dB was registered in both ears. At the age 4 yr, his first psychological test 0MSC) resulted in an IQ of 35 which did not increase noticeably in the following years, although in 1973 he scored at a level of 75. At age 13 yr his communication c’ifficulties had created so many problems with his environment that he was referred to the University of Amsterdam group. Examination
We found Johan to be a boy of normal posture with retarded motor functions but without signs of ataxia or of vestibular dysfunction. He did display a slight choreatetosis with hyperextension of hand and finger articulations. The plantar exes were of the Babinski type. The tendon reflexes of the upper and lower extremities were exaggerated, more on the left than on the right. EEG results were clearest with pharynx electrodes: they showed a focus of sharp waves at isting of two psychologists, two psycholinguists, and two special educators, one neurologist, hther I, and a physiotherapist, all of whom have contributed to the information given
CORTICAL WORD DEAFNESS: A CASE HISTORY
213
both temporal levels. Clinical and EEG information .qs well as the boy’s total communicative behavior (cf. below) pointed to a bilateml temporal lesion causing pure cortical word deafness, i.e., a selective agnosia for speech perception. He showed, moreover, signs of a nuclear cochlear deafness, perhaps as a consequence of kemicterus. Psychological testing by team members (WISC, Bender et al .) revealed a fairly normal intelligence as long as language comprehension was not involved or speech responses were not required. Typical of this is the fact tiiat the boy’s performance in tasks such as picture completion or arrangement ranged from normal to good. Pure tone perception was possible with the help of his hearing aid at threshold level to the extent that half-tone differences were distinguished. Identification by ear of different sounds (like coins rattling in a cup, a small bell ringing, finger tapping, the rattling of keys, toy instruments) revealed normal sound gnosis. The boy paid attention to indistinct human sounds like a cry or t.houting, but he gave no spontaneous attention to spoken language. It was possible to start communication with him, but this had to be done by waving at him, catching his eye, or by making signs when he was looking.
Communication While communicating, Johan watched his partner’s total behavior, hands and lips, usually in that order. In other words, he received most of his information from pantomimic expression, from (deaf) signs (if the partner knew any, which Tervoort did), and finally from lip reading. As stated, he got nothing from listening. His own production showed the same hierarchy. He imitated most of what he wanted to convey, used some deaf signs, and, on and off, added some nearly indistinct oral movements with vocalizations. That way, most of what he tried to utter was completely lost to outsidp tind remained hard to understand even for those close to him. By the same oken, what he got out of a partner’s attempts to reach him with language were haphazard single clues out of a series of trials and misunderstandings. His knowledge of the deaf signs was very slight; he did not use them in the usual abbreviated, conventionalized form but merely iconically, as imitations; moreover, he was not able to use them in sequences comparable with spoken utterances having syntactic cohesion. His most successful way of conversing was enthusiastic acting or reenacting. Once triggered by a “key” word, he would start such an act. It appeared, to be easier to trigger him through the written than through the spoken word. One example was the written letterword “TV” (normally used in Dutch for “television”) which triggered the reenacting of complete programs of Johan’s liking, mostly with a lot of fighting. shooting, and other violent excitement. A more detailed description of one OT the rare occasions on which Johan volunteered information, thus initiating a context himself, can give a fuk-
214
BERNARD T. TERVOOR?
and BERNARD
J. ANSINK
impression of the inefficiency of his communication attempts. He waved at his ner (Tervmrt), then waved aside (which meant “far, far away,” as became later) and made the sign of holding the wheel of a car ( “far away” plus “where we came from by car this morning ’ ‘) while uttering the nds Iwibibawal, but far less precisely than the notation would suggest; it cmld equally well be noted /bibipala/, /wewewa/, /piipiimala/ and all the permutatticmsthereof. As Tervoort kept making the sign for “What?” Johan added the itative sign for “baby. ” This solved the first part of his utterance insofar as it clear that he was talking about a baby far away from where he had come car. When Tervoort made the signs for “baby ” plus “yours, ” Johan vigorously, so that it could be assumed that he wanted to say something t his baby brother at home; an assumption that proved to be correct but that supposed more background or inside knowledge than a new partner usually Later information revealed that the first “word” used by Johan here was not 2, however, as was first concluded, but in all probability /wibi/, which was name of his little brother. The second “word” remained incomprehensible Jahan could not find its :+igncounterpart, until Tervoort-after several guesses---came up with the right one, which was the sign for talking or ng, Dutch /prata/. It was not until then that it was noticed that Johan was making the sign and simultaneously shaking his head, while repeating his said” was not “baby talk,‘* but: “baby not talk,” translataa~: my little brother Wibi can’t talk yet. This whole stretch of conversation well over a minute. ban’s reading competence was below that of a second grader. When asked to a very simple story at that level, he uttered sounds that could not be nized as pertaining to the words. We would deal with each word apart, either with the happy “aha” reaction of or with a shrugging of his shoulders and a face showing “gosh, we have now?“’ nalyzing words into graphemes was impossible, as was reading even a short ce as a unit of a higher order. The few words he could read were recog-
y feasible to ascribe Johan’s difficulties to his cochleonuclear deafcame about at a later age as indicated by the early normal audiog, the verbal agnosia must be considered to be the cause. The hearing n exhibited at the age of 13 yr must have developed since the time *his i audiogram had been produced, in 1970. Nuclear deafness may dein the early and middle teens in children that have been suffering from jaundice: the kemicterus is not by a long way completed in ear~:ychild-
CORTICAL WORD DEAFNESS A CASE HISTORY
215
The cause of his verbal agnosia should be sought in perinatal pathology, in which the temporal lobes can be very vulnerable. Apparently, his communicative behavior at the (pseudo)imbecil level stems exclusively from the almost complete blocking of his language development from the very onset. This is shown at the (verbal) sign level as well as at the syntactic level. His symbolic awareness has not ;et reached the developmental stage of generalization and socialization, although there is some insight into the basic functioning of a sign. insofar as he uses deaf signs and knows some words. Signing for him is easier than using words. In this respect this case is not different from other types of handicaps (Brown, 1977). A further analysis of. this visual communication would in all probability show the presence of basic grammatical relations, like the ones found by Feldman et al. ( 1977). Johan can bring two or three notions together in words, sometimes in a mere associative succession (“far away” + “car”), sometimes as an interdependence of some kind ( “baby” + “talk” + “not “). Thus the boy differs greatly from an ordinary deaf child. The latter can be reached through vision (if not also by residual hearing and vibratory and kinesthetic perception) and so is given full opportunity to arrive at a satisfactory verbal and language level during his school years. The best proof of this difference is that the school for the deaf which Johan attended has given him so little. At his age of 14 yr, the prognosis for further communicative and educational development is poor. Educationally, there was no better opportunity available, which is different from saying that it would have been impossible to create one, e.g., within the context of individual care for multiple-handicapped hearing-impaired children. Permanent institr ,onalization of a boy like Johan is too unsatisfactory a solution in present da! society. Another conclusion that emerges from this case history that might be of certam theoretical and more general value, is the fact that the reality of specific speech sound feature detectors-as described, e.g.. by Eimas and Corbit (1973)---is corroborated. The occurrence of cases of developmental pure verbal auditory agnosia amounts to clinical evidence for such a specific speech analysis system- the point being that there was no audiogl.am deafness up to 19’73 although word deafnessappears to have been present from birth. Finally, there is one last point which this case reintroduces. Developmental neurology shows some fundamental differences from general neurology concerning adults. ‘The point of departure of the latter is normal anatomical and functional development of the nervous system, from conception to full maturity; this is quite obviously not so in the case of the former. There are structural differences. However, neither developmental neurology, nor psycholinguistics, nor any other field of specialty dealing with complicated cases like this could by itself meet the challenge; the multidisciplinary approach, then, is the only possibility.
216
BERNARD T. TERVOORT and BERNARD J. ANSINK
Arnold, b. (1960). Angeborene worttaubheit. Zeitschrift fir Laryngologie und Rhinologie 39: 5259. Brown, R. (1977). Why are signed languages easier to learn than spoken languages? Keynote Address to the National Association of the Deaf. Chicago, May 3 l-June 4. Eimas, PD., and Corbit, J.D. (1973). Selective adaptation of linguistic feature detectors. Cognitive Psychof. 4: 99- 110. Feldman, H., Goldin-Meadow, S. and Gleitman, L. (1977). The creation of language by linguistically deprived children. In Action, Gesture and Symbol: The Emergence of Language. New York: Academic. Feuchtwangler, E. ( 1930). Amusia: Studien zur pathologischen Psychologie der Akustischen Wahmehmung. Monographs aus den Gesamtgebiete der Neurologie und Psychologie. Berlin: Springer-Verlag. Goldstein. M. N. (1974). Auditory agnosia for speech (“pure word deafness”). Brain and Lang. 1: 195-204. Geldstein. M. N., Brown, M., and Hollander, J. (1975). Auditory agnosia and cortical deafness: analysis of a case with three-year follow-up. Brain and Lang. 2: 324-332. Hkcaen, H. ( 1973). Introduction a la neuropsychologie. Paris. Larousse. Hm=hen, S.E. ( 1920- 1922). Klinische und Anatomische Beitriige zur Pathologie des Gehirns. Stockholm. Kteist. K. (1934). Gehirn Pathologic. Leipzig: Barth. Kkisf . K . ( 1%2). Sensory Aphasia and Amusia. Oxford: Pergamon . kpmann, H. ( 1898). Ein Fall von reiner Sprachtaubheit. Psychiatrische Abhandlungen, Breslau. bell, E. (1967). Zur Diagnose und Therapie bei Seelentaubheit. Sprachheilpadagogische und Himpathologische Probleme bei der Rehabilitation von Him- und Sprachgeschkiigten: Hamburg. leemy, M. ( 1926). Lehrbuch der Sprach- und Stimmheilkunde. Leipzig: Vogel, pp. 4 I-48. Wrster-Drought . :, . , and Allen, I.M. (1929, 1920). Congenital auditory imperception. J. Neural. andPsychopath. 9: 289, i0, 193. Wooster-Drought, C. ( 1965). Observations on congenital auditory imperception. Acta Therupeutica Vocahca et Logopedica. 1: 65 - 67.
