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Impairment of nonlinguistic hand movements in a deaf aphasic
BRAIN
AND
LANGUAGE
Impairment
3, 566-571 (1976)
of Nonlinguistic Hand Movements in a Deaf Aphasic DOREEN KIMURA University
of Western Ontario
ROBBIN BATTISON Gallaudet
College
AND BARBARA LUBERT University
of Western Ontario
A deaf man who became aphasic for sign language was seen 4 years after a left-hemisphere stroke. While not impaired on traditional apraxia tests, he was impaired, relative to nonaphasic deaf controls, in the imitation of complex nonlinguistic hand movements. He was not impaired on single isolated movements. These findings are interpreted as supporting a concept of left-hemisphere function which emphasizes complex motor control.
Disturbances of sign language in the deaf are associated with left-hemisphere damage (Burr, 1905; Critchley, 1938; Douglass & Richardson, 1959; Grasset, 18%; Leischner, 1943; Sat-no, Swisher, & Sarno, 1969; Tureen, Smolik, & Tritt, 1951)just as disorders of spoken language are, in the hearing population. Typically, the disturbance has been interpreted as one of symbolic language function, implying that behavior+nch does not involve symbols should be unimpaired. However, it has been proposed (Kimura & Archibald, 1974)that the left hemisphere’s specialized functions may not be related primarily to language, but rather to the control of complex motor behavior. Disturbances of sign language and of speech are seen in this context, as disorders of certain motor functions in which the linguistic impairment is secondary (Kimura, 1974). In support of this hypothesis, it has been found that copying of meaningless This research was supported by grants to D. Kimura from the Medical Research Council and the National Research Council, Ottawa, and by NSF Grant No. SOC-74-14724 to the Linguistics Research Laboratory, Gallaudet College, Washington, D.C. Doreen Kimura is the recipient of an Ontario Mental Health Foundation Research Associateship. Barbara Lubert is the recipient of a 1967 Science Scholarship from the National Research Council, Ottawa. Send reprint requests to Doreen Kimura, Department of Psychology, University of Western Ontario, London, Ontario, Canada N6A 5C2.
566 Copyright 0 1976 by Academic Press, Inc. All rights of reproduction in any form reserved.
HAND
MOVEMENTS
IN A DEAF
APHASIC
567
unfamiliar manual movements is impaired after left-hemisphere damage in hearing subjects, to at least the same degree as the practiced familiar acts required in traditional apraxia testing (Kimura & Archibald, 1974). It is therefore of interest to see what, if any, disorders of manual activity occurred in those cases in which signing was affected by central nervous system pathology. Unfortunately, not much detailed information is given on the question of the nonlinguistic competence of the limb in previous reports of deaf aphasics. Burr (1905) makes no statement about apraxia, and his patient is, in any case, generally impaired and unresponsive. Critchley (1938) and Tureen et al. (1951) both state that there was no apraxia in their cases of deaf aphasia, although CritchIey remarks that “The movements of the hands were manifestly erratic and jerky.” Douglass and Richardson (1959) state “neither was there evidence of non-language apraxia,” but report only on the ability of the left hand to do rhythmical tapping. Grasset (1896) reports that the right arm was incoordinated but that the patient could shake hands with it, eat and drink with it, place it on his head, etc. Leischner (1943) reported on the ability of the patient to perform a series of movements to command requiring the manipulation of real objects, e.g., lighting a candle with a match, take glasses off and put them into their case, etc., all of which he did correctly. Sarno et al. (1969) report that their patient could imitate correctly the movements of using a toothbrush, using a pencil, sweeping, etc., and also that he could correctly manipulate objects such as a comb and a razor. They state that “he did not show non-language apraxia.” In only one of these case reports is it explicitly stated that movements of comparable difficulty to signs were performed better than the movements of signing. Sarno et al. (1969) state that their patient could imitate certain practiced movements correctly, that is, movements in which the hands are accurately used in a complex sequence, without the aid of external visual guidance such as is provided by objects. It is, however, possible that he might have been able to imitate comparably easy signs correctly, and we are not told to what extent he could generate complex nonlinguistic hand movements, aside from manipulation of objects. Since we had access to a deaf aphasic, it seemed worthwhile to examine the nonlinguistic manual abilities somewhat more systematically than is usual. We employed a complex motor sequence task previously found to be highly correlated with traditional apraxia tests, but with the advantage that the movements were unfamiliar (Kimura & Archibald, 1974). This report describes our aphasic subject’s performance on this and another motor task requiring isolated finger flexion, and compares him with three deaf nonaphasic controls. He was also required to demonstrate to command and/or imitation how he would use certain objects.
568
KIMURA,
BATTISON AND LUBERT
MATERIALS
AND METHODS
Subjects The aphasic subject was a 74-year-old right-handed male who became deaf at age 6 after exposure to extreme cold. He attended residential schools for the deaf in Canada, where he acquired signs at the age of 8 or 9. He was considered a skilled signer and writer. He acquired a B. A. in English, and subsequently an honorary M. A. and an honorary doctor of laws. He was employed as a linotypist, journalist, editor, and professional organizer for deaf groups. He was thus very proficient in all forms of manual communication, and in speaking and lip-reading. Three years ago he suffered an occlusion of the left middle cerebral artery, as diagnosed by arteriography and brain scan, with a consequent hemiparesis on the right, and difficulty with spoken as well as with sign language. His defects in signing have been extensively studied and documented by Battison and Padden (Note 1) and will not be detailed here. Suffice it to say that like Leischner’s (1943) patient, this man shows typical “aphasic” errors during signing, such as substitutions, paraphasias, perseveration, etc. The patient at the time of testing was alert and cooperative and had sufficient comprehension to follow most instructions. His hemiparesis had almost completely disappeared. The three deaf nonaphasic control subjects were aged .53,66, and 79 years. Hearing loss was congenital in one, possibly congenital in another, and began at age 1 in a third, subsequent to a fall. Two ofthe three were native signers in that they were born into deaffamilies, and the third acquired signs at about age 7. All three had acquired bachelor’s degrees and two had acquired a Master’s degree. All three were right-handed.
Procedure Fingerjexion. The subject was seated with both elbows on a table, arms upright, and all fingers extended. He was asked to flex each ofeight fingers, in turn, at the middlejoint, to a90 angle. He was required to do this without flexing any otherjoints of any fingers. If he did this correctly on the first trial he received a score of 2, if correct on the second trial a score of 1, and 0 if not done correctly in two trials. The total possible score was thus 8 for each hand. This task is normally performed better by the left hand (Kimura & Vanderwolf, 1970). Movement copying. This test is described by Kimura and Archibald (1974). The subject is seated at a table facing the examiner. The examiner makes a movement pattern with one hand at a time, using the hand for demonstrating which the patient will use in copying. The present test procedure employed the first movement sequence (closed fist, thump ulnar edge on table) as a practice trial. Subsequently, five movement sequences were presented, first for one hand and then for the other, the subject simply copying each movement in turn after the examiner was finished. The five movement sequences were: (i) closed fist, thump ulnar edge on table, raise and open hand, slap palm side of hand on table, (ii) open hand with all fingers spread, held out from body and perpendicular to body axis in front of the opposite arm, hand sweeps across body from one side to other, fingers extended but closing up to contact each other while the hand is moving, (iii) extended fingers in contact, thumb extended and up, hand parallel to forehead with palm facing body, hand moved across head area at forehead level, from contralateral to ipsilateral, (iv) extended fingers and thumb in contact, back of hand slaps across the other forearm, rotates and palm slaps across other forearm in same position, and (v) fingers and thumb almost straight, tapered together so that fingertips form a ring which touches the center of the forehead, hand moves out and away from forehead, rotating to a palm outwards orientation, hand opening wide as it turns, still at forehead level. None of these complex manual sequences are in themselves signs, nor are they parts of compound signs. Interrogation of the subjects after the study indicated that the movements were not interpreted as meaningful signs. When subjects were pressed to attempt a label, they balked at
HAND MOVEMENTS
569
IN A DEAF APHASIC
TABLE 1 MEAN SCORESON Two MOTORTASKS Finger flexion Left
Right
Movement copying Left
Right
Aphasic subject
7
4
27
25
Deaf controls I 2 3
6 4 7
4 3 3
36 36 40
36 38 38
Mean of controls
5.7
3.3
37.3
37.3
doing so, saying that they were not similar enough to actual signs, and had as well a stiff quality to them which was unlike signing. All movement sequences were scored in detail for features such as hand posture, hand orientation, accuracy of movement, etc., according to criteria worked out on a neurological population. If needed, a second trial was given for each sequence, but the points given on second trials were lower than those given for correct performance on the first trial. The maximum possible score for each hand was 40. In addition to the above, the aphasic subject was asked, by finger-spelling, to show how he would use the following objects: comb, toothbrush, scissors, pencil, and spoon. He was also asked to show how he would wave goodbye. He was then asked to imitate the examiner, who simulated the movements of using the same five objects.
RESULTS
The scores for each hand on finger flexion and movement copying are given for all four subjects in Table 1. It is clear that the deaf aphasic is impaired on movement copying, but not on finger flexion. There is no overlap between his movement copying scores and those of the controls, for either hand. A Mann-Whitney U test on the two hand scores of the aphasic subject and the six scores of the nonaphasics yields a U value of 0 (p < .036, one-tailed), indicating a significant difference (Siegel, 1956). His score is very similar to that of a group of hearing patients with vascular accidents to the left hemisphere (mean = 25.6, n = 19) and considerably lower than that of a group with right-hemisphere damage (mean = 33.7, n = 13). Thus, despite many years of using his hands for complex movements and the fact that he was seen 4 years poststroke, this man is clearly impaired on a complex nonlinguistic movement task. This impairment was still evident on retesting a few months later, indicating that it is a reliable deficit. The aphasic subject was asked to demonstrate how to use various objects (without the object present). He demonstrated comb and scissors by using body part as object, but for scissors this movement is also the
570
KIMURA,
BATTISON
AND LUBERT
correct sign in sign language. Toothbrush, pencil, and spoon were all demonstrated correctly, and he also showed how to wave goodbye correctly. When asked to imitate the examiner’s use of comb, scissors, toothbrush, pencil, and spoon, he did so exactly, although for comb and scissors these had not been the movements he first made. He also showed no difficulty in manipulating real objects correctly. His praxic abilities are thus strictly comparable to the patients described by Leischner (1943) and Sarno et al. (1969). DISCUSSION Our deaf subject with aphasia was found to be impaired in imitating a sequence of complex hand movements which were unfamiliar and which were not in themselves signs or parts of compound signs. Thus he was impaired in performing nonlinguistic, as well as linguistic, manual movements. On traditional apraxia testing, when asked to show how he would use certain common objects, he was minimally, if at all, impaired, and in imitation of a demonstrator’s object use, he was very accurate. No difficulty in manipulating real objects was detected in this man. Liepmann many years ago made the point that, of the tests of apraxia which were usually made, manipulation of real objects was least likely to be affected since “the objects provide certain reference points for manipulation” (1908, p. 15). Next in difficulty came imitation of familiar (“purposive”) movements, and most difficult of all was the simulation of the use of objects in their absence. The only one of these tests on which our patient might be said to have any difficulty was in the latter, where on at least one occasion he used body part as object. Kimura and Archibald (1974) have shown that the movement sequences need not be familiar nor capable of being verbally mediated for an impairment to be demonstrated in apraxic hearing patients. In fact, the impairment in control of complex movement seen in apraxia is more readily detected by presentation of unfamiliar hand movements, presumably because this material is more difficult. Evidence that the unfamiliar movements are, in general, more difficult than the familiar traditional apraxia tests (at least as the latter are typically scored) comes from the finding that Kimura and Archibald’s (1974) patients with right-hemisphere damage scored 100% in demonstrating or imitating object use but only 80% in imitating the unfamiliar movements. Neither do most normal subjects obtain perfect scores on this task. Thus, the relative difficulty which our patient demonstrated on the movement copying task is presumably due to the fact that it is a more demanding task even, than the simulation of object use. This finding underscores the necessity, when claiming a strictly linguistic impairment after brain damage, for testing nonlinguistic functions with
HAND MOVEMENTS
IN A DEAF APHASIC
571
material of comparable difficulty to the linguistic. While there is no simple way of equating task demands, it is quite possible that the degree of impairment seen in our subject on the linguistic hand movements parallels that of the nonlinguistic, that is, that his defect is primarily one of motor sequencing. This interpretation would accord well with the proposal that the left hemisphere is specialized primarily for certain types of motor control, and that its important role in language functions is derived from the former (Kimura, 1974). REFERENCES Burr, C. W. 1905.Loss of the sign language in a deaf mute from cerebral tumor and softening. New York Medical Journal, 81, 1106- 1108. Douglass, E., &Richardson, J. C. 1959.Aphasiain acongenital deaf-mute.Brain, 82,68-80. Grasset, J. 1896.Aphasie de la main droite chez un sourd-muet. Le Progr>s Midical, 4, 169. Kimura, D. 1974. The neural basis of language qua gesture (University of Western Ontario Research Bulletin #292). To be published in H. Avakian-Whitaker & H. A. Whitaker (Eds.), Studies in neurolinguistics. New York: Academic Press. Kimura, D., & Archibald, Y. 1974. Motor functions of the left hemisphere. Brain, 97, 337-350. Kimura, D., & Vanderwolf, C. H. 1970. The relation between hand preference and the performance of individual finger movements by left and right hands. Brain, 93, 769-774. Leischner, A. 1943. Die “Aphasie” der Taubstummen. Archiv fir Psychiatric und Nervenkrankheiten,
115, 469-548.
Liepmann, H. 1908.Drei Aufsiitze aus dem Apraxiegebiet. Berlin: Karger. Samo, J. E., Swisher, L. P., & Samo, M. T. 1969.Aphasia in acongenitallydeaf man. Cortex, 5, 398-414. Siegel, S. 1956. Nonparametric statistics for the behavioral sciences. Tokyo: Kogakusha. Tureen, L. L., Smolik, E. A., & Tritt, J. H. 1951. Aphasia in a deaf mute. Neurology, 1, 237-244.
REFERENCE
NOTE
1. Battison, R., & Padden, C. sign language aphasia: A case study. Paper presented at the 49th meeting of the Linguistic Society of America, New York, 1974.
AND
LANGUAGE
Impairment
3, 566-571 (1976)
of Nonlinguistic Hand Movements in a Deaf Aphasic DOREEN KIMURA University
of Western Ontario
ROBBIN BATTISON Gallaudet
College
AND BARBARA LUBERT University
of Western Ontario
A deaf man who became aphasic for sign language was seen 4 years after a left-hemisphere stroke. While not impaired on traditional apraxia tests, he was impaired, relative to nonaphasic deaf controls, in the imitation of complex nonlinguistic hand movements. He was not impaired on single isolated movements. These findings are interpreted as supporting a concept of left-hemisphere function which emphasizes complex motor control.
Disturbances of sign language in the deaf are associated with left-hemisphere damage (Burr, 1905; Critchley, 1938; Douglass & Richardson, 1959; Grasset, 18%; Leischner, 1943; Sat-no, Swisher, & Sarno, 1969; Tureen, Smolik, & Tritt, 1951)just as disorders of spoken language are, in the hearing population. Typically, the disturbance has been interpreted as one of symbolic language function, implying that behavior+nch does not involve symbols should be unimpaired. However, it has been proposed (Kimura & Archibald, 1974)that the left hemisphere’s specialized functions may not be related primarily to language, but rather to the control of complex motor behavior. Disturbances of sign language and of speech are seen in this context, as disorders of certain motor functions in which the linguistic impairment is secondary (Kimura, 1974). In support of this hypothesis, it has been found that copying of meaningless This research was supported by grants to D. Kimura from the Medical Research Council and the National Research Council, Ottawa, and by NSF Grant No. SOC-74-14724 to the Linguistics Research Laboratory, Gallaudet College, Washington, D.C. Doreen Kimura is the recipient of an Ontario Mental Health Foundation Research Associateship. Barbara Lubert is the recipient of a 1967 Science Scholarship from the National Research Council, Ottawa. Send reprint requests to Doreen Kimura, Department of Psychology, University of Western Ontario, London, Ontario, Canada N6A 5C2.
566 Copyright 0 1976 by Academic Press, Inc. All rights of reproduction in any form reserved.
HAND
MOVEMENTS
IN A DEAF
APHASIC
567
unfamiliar manual movements is impaired after left-hemisphere damage in hearing subjects, to at least the same degree as the practiced familiar acts required in traditional apraxia testing (Kimura & Archibald, 1974). It is therefore of interest to see what, if any, disorders of manual activity occurred in those cases in which signing was affected by central nervous system pathology. Unfortunately, not much detailed information is given on the question of the nonlinguistic competence of the limb in previous reports of deaf aphasics. Burr (1905) makes no statement about apraxia, and his patient is, in any case, generally impaired and unresponsive. Critchley (1938) and Tureen et al. (1951) both state that there was no apraxia in their cases of deaf aphasia, although CritchIey remarks that “The movements of the hands were manifestly erratic and jerky.” Douglass and Richardson (1959) state “neither was there evidence of non-language apraxia,” but report only on the ability of the left hand to do rhythmical tapping. Grasset (1896) reports that the right arm was incoordinated but that the patient could shake hands with it, eat and drink with it, place it on his head, etc. Leischner (1943) reported on the ability of the patient to perform a series of movements to command requiring the manipulation of real objects, e.g., lighting a candle with a match, take glasses off and put them into their case, etc., all of which he did correctly. Sarno et al. (1969) report that their patient could imitate correctly the movements of using a toothbrush, using a pencil, sweeping, etc., and also that he could correctly manipulate objects such as a comb and a razor. They state that “he did not show non-language apraxia.” In only one of these case reports is it explicitly stated that movements of comparable difficulty to signs were performed better than the movements of signing. Sarno et al. (1969) state that their patient could imitate certain practiced movements correctly, that is, movements in which the hands are accurately used in a complex sequence, without the aid of external visual guidance such as is provided by objects. It is, however, possible that he might have been able to imitate comparably easy signs correctly, and we are not told to what extent he could generate complex nonlinguistic hand movements, aside from manipulation of objects. Since we had access to a deaf aphasic, it seemed worthwhile to examine the nonlinguistic manual abilities somewhat more systematically than is usual. We employed a complex motor sequence task previously found to be highly correlated with traditional apraxia tests, but with the advantage that the movements were unfamiliar (Kimura & Archibald, 1974). This report describes our aphasic subject’s performance on this and another motor task requiring isolated finger flexion, and compares him with three deaf nonaphasic controls. He was also required to demonstrate to command and/or imitation how he would use certain objects.
568
KIMURA,
BATTISON AND LUBERT
MATERIALS
AND METHODS
Subjects The aphasic subject was a 74-year-old right-handed male who became deaf at age 6 after exposure to extreme cold. He attended residential schools for the deaf in Canada, where he acquired signs at the age of 8 or 9. He was considered a skilled signer and writer. He acquired a B. A. in English, and subsequently an honorary M. A. and an honorary doctor of laws. He was employed as a linotypist, journalist, editor, and professional organizer for deaf groups. He was thus very proficient in all forms of manual communication, and in speaking and lip-reading. Three years ago he suffered an occlusion of the left middle cerebral artery, as diagnosed by arteriography and brain scan, with a consequent hemiparesis on the right, and difficulty with spoken as well as with sign language. His defects in signing have been extensively studied and documented by Battison and Padden (Note 1) and will not be detailed here. Suffice it to say that like Leischner’s (1943) patient, this man shows typical “aphasic” errors during signing, such as substitutions, paraphasias, perseveration, etc. The patient at the time of testing was alert and cooperative and had sufficient comprehension to follow most instructions. His hemiparesis had almost completely disappeared. The three deaf nonaphasic control subjects were aged .53,66, and 79 years. Hearing loss was congenital in one, possibly congenital in another, and began at age 1 in a third, subsequent to a fall. Two ofthe three were native signers in that they were born into deaffamilies, and the third acquired signs at about age 7. All three had acquired bachelor’s degrees and two had acquired a Master’s degree. All three were right-handed.
Procedure Fingerjexion. The subject was seated with both elbows on a table, arms upright, and all fingers extended. He was asked to flex each ofeight fingers, in turn, at the middlejoint, to a90 angle. He was required to do this without flexing any otherjoints of any fingers. If he did this correctly on the first trial he received a score of 2, if correct on the second trial a score of 1, and 0 if not done correctly in two trials. The total possible score was thus 8 for each hand. This task is normally performed better by the left hand (Kimura & Vanderwolf, 1970). Movement copying. This test is described by Kimura and Archibald (1974). The subject is seated at a table facing the examiner. The examiner makes a movement pattern with one hand at a time, using the hand for demonstrating which the patient will use in copying. The present test procedure employed the first movement sequence (closed fist, thump ulnar edge on table) as a practice trial. Subsequently, five movement sequences were presented, first for one hand and then for the other, the subject simply copying each movement in turn after the examiner was finished. The five movement sequences were: (i) closed fist, thump ulnar edge on table, raise and open hand, slap palm side of hand on table, (ii) open hand with all fingers spread, held out from body and perpendicular to body axis in front of the opposite arm, hand sweeps across body from one side to other, fingers extended but closing up to contact each other while the hand is moving, (iii) extended fingers in contact, thumb extended and up, hand parallel to forehead with palm facing body, hand moved across head area at forehead level, from contralateral to ipsilateral, (iv) extended fingers and thumb in contact, back of hand slaps across the other forearm, rotates and palm slaps across other forearm in same position, and (v) fingers and thumb almost straight, tapered together so that fingertips form a ring which touches the center of the forehead, hand moves out and away from forehead, rotating to a palm outwards orientation, hand opening wide as it turns, still at forehead level. None of these complex manual sequences are in themselves signs, nor are they parts of compound signs. Interrogation of the subjects after the study indicated that the movements were not interpreted as meaningful signs. When subjects were pressed to attempt a label, they balked at
HAND MOVEMENTS
569
IN A DEAF APHASIC
TABLE 1 MEAN SCORESON Two MOTORTASKS Finger flexion Left
Right
Movement copying Left
Right
Aphasic subject
7
4
27
25
Deaf controls I 2 3
6 4 7
4 3 3
36 36 40
36 38 38
Mean of controls
5.7
3.3
37.3
37.3
doing so, saying that they were not similar enough to actual signs, and had as well a stiff quality to them which was unlike signing. All movement sequences were scored in detail for features such as hand posture, hand orientation, accuracy of movement, etc., according to criteria worked out on a neurological population. If needed, a second trial was given for each sequence, but the points given on second trials were lower than those given for correct performance on the first trial. The maximum possible score for each hand was 40. In addition to the above, the aphasic subject was asked, by finger-spelling, to show how he would use the following objects: comb, toothbrush, scissors, pencil, and spoon. He was also asked to show how he would wave goodbye. He was then asked to imitate the examiner, who simulated the movements of using the same five objects.
RESULTS
The scores for each hand on finger flexion and movement copying are given for all four subjects in Table 1. It is clear that the deaf aphasic is impaired on movement copying, but not on finger flexion. There is no overlap between his movement copying scores and those of the controls, for either hand. A Mann-Whitney U test on the two hand scores of the aphasic subject and the six scores of the nonaphasics yields a U value of 0 (p < .036, one-tailed), indicating a significant difference (Siegel, 1956). His score is very similar to that of a group of hearing patients with vascular accidents to the left hemisphere (mean = 25.6, n = 19) and considerably lower than that of a group with right-hemisphere damage (mean = 33.7, n = 13). Thus, despite many years of using his hands for complex movements and the fact that he was seen 4 years poststroke, this man is clearly impaired on a complex nonlinguistic movement task. This impairment was still evident on retesting a few months later, indicating that it is a reliable deficit. The aphasic subject was asked to demonstrate how to use various objects (without the object present). He demonstrated comb and scissors by using body part as object, but for scissors this movement is also the
570
KIMURA,
BATTISON
AND LUBERT
correct sign in sign language. Toothbrush, pencil, and spoon were all demonstrated correctly, and he also showed how to wave goodbye correctly. When asked to imitate the examiner’s use of comb, scissors, toothbrush, pencil, and spoon, he did so exactly, although for comb and scissors these had not been the movements he first made. He also showed no difficulty in manipulating real objects correctly. His praxic abilities are thus strictly comparable to the patients described by Leischner (1943) and Sarno et al. (1969). DISCUSSION Our deaf subject with aphasia was found to be impaired in imitating a sequence of complex hand movements which were unfamiliar and which were not in themselves signs or parts of compound signs. Thus he was impaired in performing nonlinguistic, as well as linguistic, manual movements. On traditional apraxia testing, when asked to show how he would use certain common objects, he was minimally, if at all, impaired, and in imitation of a demonstrator’s object use, he was very accurate. No difficulty in manipulating real objects was detected in this man. Liepmann many years ago made the point that, of the tests of apraxia which were usually made, manipulation of real objects was least likely to be affected since “the objects provide certain reference points for manipulation” (1908, p. 15). Next in difficulty came imitation of familiar (“purposive”) movements, and most difficult of all was the simulation of the use of objects in their absence. The only one of these tests on which our patient might be said to have any difficulty was in the latter, where on at least one occasion he used body part as object. Kimura and Archibald (1974) have shown that the movement sequences need not be familiar nor capable of being verbally mediated for an impairment to be demonstrated in apraxic hearing patients. In fact, the impairment in control of complex movement seen in apraxia is more readily detected by presentation of unfamiliar hand movements, presumably because this material is more difficult. Evidence that the unfamiliar movements are, in general, more difficult than the familiar traditional apraxia tests (at least as the latter are typically scored) comes from the finding that Kimura and Archibald’s (1974) patients with right-hemisphere damage scored 100% in demonstrating or imitating object use but only 80% in imitating the unfamiliar movements. Neither do most normal subjects obtain perfect scores on this task. Thus, the relative difficulty which our patient demonstrated on the movement copying task is presumably due to the fact that it is a more demanding task even, than the simulation of object use. This finding underscores the necessity, when claiming a strictly linguistic impairment after brain damage, for testing nonlinguistic functions with
HAND MOVEMENTS
IN A DEAF APHASIC
571
material of comparable difficulty to the linguistic. While there is no simple way of equating task demands, it is quite possible that the degree of impairment seen in our subject on the linguistic hand movements parallels that of the nonlinguistic, that is, that his defect is primarily one of motor sequencing. This interpretation would accord well with the proposal that the left hemisphere is specialized primarily for certain types of motor control, and that its important role in language functions is derived from the former (Kimura, 1974). REFERENCES Burr, C. W. 1905.Loss of the sign language in a deaf mute from cerebral tumor and softening. New York Medical Journal, 81, 1106- 1108. Douglass, E., &Richardson, J. C. 1959.Aphasiain acongenital deaf-mute.Brain, 82,68-80. Grasset, J. 1896.Aphasie de la main droite chez un sourd-muet. Le Progr>s Midical, 4, 169. Kimura, D. 1974. The neural basis of language qua gesture (University of Western Ontario Research Bulletin #292). To be published in H. Avakian-Whitaker & H. A. Whitaker (Eds.), Studies in neurolinguistics. New York: Academic Press. Kimura, D., & Archibald, Y. 1974. Motor functions of the left hemisphere. Brain, 97, 337-350. Kimura, D., & Vanderwolf, C. H. 1970. The relation between hand preference and the performance of individual finger movements by left and right hands. Brain, 93, 769-774. Leischner, A. 1943. Die “Aphasie” der Taubstummen. Archiv fir Psychiatric und Nervenkrankheiten,
115, 469-548.
Liepmann, H. 1908.Drei Aufsiitze aus dem Apraxiegebiet. Berlin: Karger. Samo, J. E., Swisher, L. P., & Samo, M. T. 1969.Aphasia in acongenitallydeaf man. Cortex, 5, 398-414. Siegel, S. 1956. Nonparametric statistics for the behavioral sciences. Tokyo: Kogakusha. Tureen, L. L., Smolik, E. A., & Tritt, J. H. 1951. Aphasia in a deaf mute. Neurology, 1, 237-244.
REFERENCE
NOTE
1. Battison, R., & Padden, C. sign language aphasia: A case study. Paper presented at the 49th meeting of the Linguistic Society of America, New York, 1974.