Aphasia. in Children. aetiology of congenital aphasia which has been carried out at Manchester

Transcription

1 Aphasia in Children By ALEX W. G. EWING, M.A., Ph.D. The following notes treat of aphasia in children from two points of view?diagnosis and education. They are based on the results of an investigation into the aetiology of congenital aphasia which has been carried out at Manchester University and which has occupied five years. An intensive study was made of ten " aphasic " boys and girls. Seven of these were dumb and totally deaf to speech before receiving education by special methods. The three others suffered from gross defects of speech and language. In one only instance was there any history of or injury serious illness. Since the usual tests for hearing were ineffective it was necessary to devise special tests of hearing. The most important of these were given to the ten aphasic children, 12 boys and girls attending a public elementary school for normal children, 71 pupils in a residential school for the deaf and 7 deaf and normal adults. Performance tests of intelligence were used and also reading tests after a period of education. Daily experience throughout the research, in teaching aphasic boys and girls by special methods, afforded most valuable data. It was possible to keep a detailed record in diary form of the development of speech and of the power to understand what was said to them in these patients, who, before special

2 2 MENTAL WELFARE teaching, had been dumb and deaf to words. The record also covered progress in reading, writing, general education and behaviour under all the conditions of daily life. Finally, an answer was sought to the question " Is congenital aphasia, of the type found among these children, comparable to the aphasia in adults which has been so much studied?" The defects of the children prevent The dis- or seriously limit the natural development of speech and language. orders brought about in adults by injury or disease result in the disintegration of these functions when the maturity of their normal development has been reached. Are there any common factors and are we justified in calling both forms of trouble " aphasia "? In this part of the use was investigation made of the literature of aphasia, as represented by the data and conclusions of outstanding workers from Broca to Head. Two adult came to aphasics the writer for "re-education" during the final year of the research and thus it was possible to apply the same standards to them as to the children who were being studied. A detailed account of the whole investigation, with histories of the patients, is now in the press ("Aphasia in Children," by A. W. G. Ewing, with an Introduction by E. D. Adrian, Fellow and Lecturer of Trinity College, Cambridge, to be published by the Oxford Medical Publications). In these notes it is only possible to refer to conclusions, not to all the data on which they rest. (1) Relation of Speech to Hearing. The fact that severe or total deafness, whether congenital or occurring during the vital period of natural speech development from one to five years, results in dumbness or defective speech will be familiar. Provision has been made in the educational system for the severely deaf child, and to a far less adequate degree for the partially deaf child. But the investigation to which these notes refer showed beyond doubt that the general fact that dumbness is usually due to deafness is not enough. There is a great body of scientific data, accumulated during the last fifteen or twenty years by workers in pure physics, experimental psychology and telephone en- gineering, which should revolutionise the present methods of testing hearing and of educating the partially deaf. The analysis of the sounds of speech by quantitative methods by Stumpf, Miller and Crandall have made it possible problem before which the " routine-tests " of hearing of diagnosis had broken down. for us at Manchester to solve a and the usual methods (2) High Frequency Deafness. General Characteristics. Six of the congenitally " aphasic " boys and girls who were studied intensively were found to suffer from a form of deafness apparently unrecognised hitherto, to which I have given the description, " high-frequency deafness," on account of its most striking feature, lack of hearing for sound-vibrations of high frequency or pitch, combined with normal or approximately normal hear-

3 ing MENTAL WELFARE 3 for low tones. This from the more familiar forms of cochlear or nerve auditory trouble on account of certain constant characteristics of the deafness itself and by the fact that in several condition was found to be distinguishable instances an aural examination by Dr. H. C. Smith revealed no pathological symptoms in the canal, membrane or ossicles. It had proved impossible to investigate the condition of these six patients by the " accepted methods. One was recorded as aphasic." With regard to two private patients of Mrs. Ewing's and my own, consultants had suggested that they were totally deaf, could hear, or diagnosis had been withheld. One boy after a fortnight's observation and test in a special clinic was said to have normal hearing. The two remaining patients had been classified as deaf. Four of the six were pupils at a school for the deaf, where the opinion was expressed that they were " queer " and unlike the other boys and girls. Before being taught by special methods they could not understand speech or talk. Occasionally they showed that they had heard or recognised noises, but in general their reaction to sound apart from speech seemed to be marked by that extreme variability which is characteristic of aphasia in adults. One of the private patients, a little boy of 4^ years, was brought to me early in His father, who is in medical practice, stated that he not to appeared be able to notice the noise of a motor-horn sounded a few feet away. Yet a excited cries few weeks after I had begun to teach him he shewed plainly by and gesture that he had recognised the noise of a stationary motor which was some thirty yards away, out of sight and in a place where he had certainly never seen a car. Later, when this little boy had been taught to speak, he recognised and remarked on the noise of a steamer's fog-horn coming from the distance of about a mile. The explanation of this apparent variability has been found and will be described later. Inquiry has shown that there is a real danger that " high-frequency deafness " may be taken for mental deficiency. It is a condition leading to apparently inconsistent behaviour. The patient cannot understand speech, yet his voice is natural and not monotonous like the ordinary deaf child's. He appears indifferent to sound in general, yet he does not, like the untaught deaf child, shuffle his feet in walking. In the early years of life and before special teaching has been given an extraordinarily rapid flickering of attention from object to object has been noticed. A medical observer described this as " bird-wittedness." High-frequency deafness is not, however, a form of general mental defect. The evidence for this is clear. Dr. James Drever kindly allowed us to test the general intelligence of our patients with his " Performance Tests of Intelligence " prior to their publication in These tests can be given without the use of words by either experimenter or subject for and this type of work they appear to be a great improvement on previous mental or performance tests. The high-frequency deaf children made scores which were quite incon- sistent with general mental defect. One boy's score at 8 years was equal to

4 4 MENTAL WELFARE Dr. Drever's norm for normal children of years, and his norm for deaf children of 14 years. The excellent progress of high-frequency deaf children when taught by special methods is an equally strong proof of their normal general intelligence. (3) High-Frequency Deafness and Speech. The essential characteristics of high-frequency deafness were found to be, first, normal or approximately normal hearing for low tones; the standard of normality was based on actual quantitative testing of normal, " aphasic " and deaf children. Secondly, there was a lack of acuity for high tones, evenly binaural, beginning at C1 (256 v.d.) and increasing steadily from octave to octave above that pitch. This condition was conclusively proved to have a remarkable effect on the recognition of sounds by the child. Full details are given in my book. Briefly, the effect of high-frequency deafness is as follows. The child hears voices, but the sounds of speech, vowels and consonants are all flattened out. What he hears resembles the murmuring effect which we get when listening to the sound of conversation in another room. We hear the rise and fall of the voices, we may be able to guess whether we are listening to a quiet talk or a violent argument but the essential characteristics of vowels and consonants cannot reach us. No wonder that the high-frequency deaf child who has never heard speech more distinctly than this cannot learn to talk through natural development and imitation. He recognises tones of voice which express strong emotions, love, anger and the rest. But can ordinary quiet speech have no meaning whatever. Consequently, he ignores speech altogether. gation has shown that the high-frequency deaf child, for the same reason, is indifferent to noises. The essential quality Our investi- of most noises and of the sounds as the sound produced by musical instruments is inaudible to him. So long has components of a pitch lower than C1 he hears something resembling a dull thud. The little boy already mentioned must have recognised the sound of the motor car by the rhythm of the thuds. But in general, one noise very much resembles another and so fails to rouse attention or interest. The methods by which high-frequency deaf children have been successfully taught to hear and understand speech and to recognise other sounds within a limited range of distance, are described below. (4) The Diagnosis of High-Frequency Deafness. The only effective means of diagnosing this form of deafness has proved to be a specially devised test of hearing. Until the child has received a considerable measure of education by special methods, successful testing bv the comparative air- and bone-conduction methods (Rinne, etc.), by the " absolute bone-conduction " method or the calculation of hearing distance for the sound of tuning-forks, etc., is completely impossible. The untaught high-frequency

5 MENTAL WELFARE 5 deaf child cannot understand the instructions, is incapable of the necessary acts of attention, and is not in the least interested in pure tones. The diagnosis of high-frequency deafness at Manchester University has been carried out with a Western Electric 2A Audiometer. The final source of the sound is a telephone receiver which the patient holds to either the right or left ear. The attention and interest of the child are won by a section of a The child is trained to illuminate a tunnel becomes audible to him. without the use of words. The procedure includes a specially constructed model railway. by depressing a key when any sound in the telephone The test can be given series of practices through which the child learns what he is required to do, and a rigorous system of checking the results. The time occupied by the test is usually from fifteen to twenty minutes. Full details of the apparatus, procedure and results with normal, "aphasic" (including high-frequency deaf), and deaf children are given in " Aphasia in Children." (5) The Education of High-Frequency Deaf Children. The high-frequency deaf children whom we studied had to be taught to understand what is said to them and to speak, It is possible that there are instances where the incidence of this form of trouble is less severe and where there is a partial development of speech through the natural processes of hearing and imitation. Only further investigation can elucidate this point. The methods which have proved most successful in teaching highfrequency deaf children to speak and within limitations of distance to understand speech by hearing were adapted from those employed in educating the deaf. Since, at the beginning, hearing was useless as a way-in to the child's brain and mind, a fresh start had to be made through sight and touch. The children were taught to watch the face of a speaker and to lip-read. The natural bent of their interests was observed and the teacher talked simply and naturally to them about their interests, taking care to make opportunities for repeating the most important words many times. From the beginning the teacher made a point of saying such words close to the child's ear immediately after they had been offered for lip-reading. The child's first imperfect attempts to imitate words in order to express his needs were encouraged. As the child's education proceeded on these lines he was taught to use his more hearing and sight less. There is first a period when the high-frequency deaf child can only recognise most of the words and phrases he knows by lip-reading and a few by hearing. Then he is able to understand practically all familiar words through hearing. Later comes a stage when he can learn many new words ear by alone. I have found that with patients of this type the power to follow my speech by ear alone preceded and for several years at least has been ahead of the power to follow other speakers through hearing. Practice seems to be the chief factor responsible. It has been stated that the child hears best what is said close to his ear. It

6 6 MENTAL WELFARE is important not to shout or raise the voice unduly. The principles and scientific data governing the methods of ear-training are explained in "Aphasia in Children." As the speaker goes further from the child or lowers the intensity of his voice, the sounds heard by the child prove less and less intelligible to him until he can only catch the murmuring described earlier. But the high-frequency deaf child after or during training is never in the position he occupied before being taught. He makes the most of every possible clue and if he can only hear fragments of words and phrases will often succeed in re-constructing the whole from the context and the general situation. In addition he will, if he can, supplement his hearing by lip-reading. The high-frequency deaf children whom we investigated could not under the most favourable conditions learn to recognise some of the consonants by sound. But they have been able, after three or four years of special teaching, to follow an unknown story told in language suitable to their age, behind their backs. As the loudness of the speech reaching their ears is progressively dimin- ished, first the consonants which they can usually hear become unrecognisable and the unemphasised syllables of words or sentences are completely lost, then the less loud vowels become blurred and finally only the murmur of voice is left. Not only has practice been given in listening systematic language lessons but also listening games have succeeded in giving the child the conscious pleasure to conversation and to have been devised which of achievement and the satisfaction of realising his progress under certain definite conditions. Practice in listening to the speech of others besides the teacher has been given as soon as effective responses can be obtained. There is great value in teach- ing high-frequency deaf children to discriminate between, remember and recognise the sounds of musical toys and ordinary noises. The best results are only to be obtained by the application of some knowledge as to the composition and relative loudness of various sounds of this type, otherwise there is the the failure of possibility that both teacher and child may be disappointed by the latter to recognise what seem to the normal listener peculiarly noticeable differences. The speech of the little boy who came to me at the age of 4^ years and has been mentioned already, is now after 5 years of teaching, normal in pronunciation and in vocabulary considerably in advance of many normal children of his age. Detailed evidence for this statement is given in "Aphasia in Children." This means, that though the first five years of life, the vital years for natural speech development, had almost ended before he learned a single word, he has in the five subsequent years of special teaching, reached the same standard in language as the ordinary normal child of ten who has heard perfectly from birth. Other high-frequency deaf children have made great though not so rapid progress towards normality. This progress cannot be obtained without the application of other special

7 MENTAL WELFARE 7 methods besides that already described. The little boy just mentioned has only recently successfully learned to say the consonant " s." The teacher requires a detailed knowledge of phonetics and of the adjustments of the speech organs by which the various vowels and consonants are produced. Incessant attention to those which prove difficult is necessary for months or even years. Since the high-frequency deaf child as described above only hears the emphasised vowels of words and sentences, spoken under ordinary conditions (i.e., when he is not having his lessons) at a short distance from him, he speaks, in the earlier stages of his education, as he hears. He utters the vowels which he hears and the consonants which are most easy to lip-read. Unemphasised " syllables and monosyllabic unemphasised words such as a," " to," " the," do not appear in his spontaneous speech. To correct this, efforts to foster a love of reading have an proved invaluable supplement to training in hearing and lip-reading. It is significant that within nine months of first being taught the patient whose progress has been most rapid, was reading the numbers on the tram-cars and as far as he could, the advertisements. Now at 10 years, he devours any book that he can lay hands on, including his elder sister's school histories. His special joy is books about railways and ships and natural history, which he can discuss with no small degree of technical knowledge. The great advantage to high-frequency deaf children of the printed word, is that it gives them without effort on their part complete impressions of words and sentences. Where progress in reading has been slower, the acquisition of speech and language has also been markedly slower, as regards both pronunciation, syntax and vocabulary. (6) Linguistic Retardation. Four of the ten aphasic patients who were studied were intensively found to have normal hearing. None of them had any physical abnormality or history of injury or serious illness. Perhaps the most striking among the four was a girl who was first taught, at the age of 4 years 9 months, by Mrs. Ewing. She had been diagnosed as congenitally deaf and like the high-frequency deaf children could neither speak nor understand any words. She was taught by die same methods as were applied to them. She is now a waitress in a small hotel. It was not until she was tested with the 2A audiometer at Manchester University that it was proved that she was not deaf. Yet she states that she still has occasional difficulty in understanding what strangers say. A boy of 12 years whose speech was for the most part unintelligible, who had a limited vocabulary and could read very little, though he had been several years at school, was brought to me. Since inability to articulate certain consonants was the most marked defect in his speech, some degree of highfrequency deafness might have been suspected. But he proved to have normal hearing when the audiometer test was given. He was taught by the help of S1ght and touch, as supplements to hearing, to articulate correctly. Progress

8 8 MENTAL WELFARE in reading became possible as he learned to use the newly developed normal speech at all times. His work at school improved in every direction. It was clear that his previous inability to answer questions and to read aloud intelligibly was largely responsible for his general backwardness. A little boy of seven could only speak in short phrases of a few simple words, which were incorrectly articulated and run together into one word. " Robinson Crusoe " was " Bisensis." He had been diagnosed as having low- grade general intelligence, but his score with the Drever Performance Tests was higher than the norms for normal and deaf children of the same age. Close observation of his behaviour and his subsequent progress in learning to speak correctly also indicated that his defect was specific and affected speech and language only. The method of teaching, since in the first place direct imitation through hearing was ineffective, was to use the patient's sight and touch to obtain normal articulation, then to train him to listen more attentively and accurately to his own and other's speech, so that the natural functions by which the ordinary child learns to speak was stimulated to play their proper part. Reading lessons were most helpful towards normalising this patient's articulation and syntax, and in increasing his vocabulary. The fourth patient whom the audiometer test showed to have normal hearing was reported to be unable to learn to read or write and consequently to be very backward indeed as regards general education. At school she was placed in a special class for dull children. She was fourteen years old and was a pupil at a well-known public school for girls. There have been more studies of this form of trouble among children than of those in which the defective use and understanding of the spoken word is the most marked symptom In this instance general intelligence proved normal, vision and visual memory were excellent and at first sight hearing and speech were completely normal. But the full nature of the defect was revealed when it was discovered that vocabulary was sub-normal and the power of imitation of words heard very limited. In a small space it is impossible to give an adequate description of the methods by which this patient was taught to read and write. She became able to read books normal to her age with pleasure and to write a letter with but occasional mistakes. It was only possible for her to have a limited period of teaching by special methods. In "Aphasia in Children " I have given detailed records of patients with quotations from my notes of their understanding and use of words from the time when I first began to observe and teach them. The comparative analysis, by identical methods, of the congenital defects discovered in the four patients found to have normal hearing, and of those in adult aphasics described by Head, von Monakow, Henschen and other leading workers, with my own two adult aphasic patients as a connecting link, led to an unhesitating conclusion that as we congenital aphasia, have met it in this investigation at Manchester University, has no essential features in common

9 MENTAL WELFARE 9 with the disorders caused by disease or injury to the brain. To apply the same term to both forms of defect seems only likely to hinder progress in the proper understanding of a very serious, yet as this research has shown, no means by unsurmountable type of trouble among children. The most efficient method of diagnosing it has proved to be, first its differentiation from high-frequency deafness by means of the hearing test described in an earlier section, and secondly a close comparison of the child's condition as regards speech with the scientific studies of normal speech development by Stern, Jespersen, De Laguna, Descceudres and other workers. On the basis of this comparative analysis the defects of the non-deaf " aphasic " children were found to be a limitation or arrest of speech and language development at a certain specific stage in each individual case. Normal children make the same mistakes but through the operation of natural processes of growth and experience become able to correct them and pass on to the next stage. Since neither hearing nor general intelligence proved sub- normal in these patients, I have described their defect as "linguistic retarda- tion."