Monograph of the American Association of Mental Deficiency最新文献

Operant conditioning techniques were applied to the study of stereotyped body-rocking movements. Six mentally retarded children were tested individually in a fully automated situation under the following conditions: (a) free operant baseline; (b) intense auditory stimulation; (c) variable-interval (VI) and fixed-ratio (FR) reinforcement schedules; (d) differential reinforcement of low rate (DRL); (e) differential reinforcement of other behaviors (DRO); and (f) noncontingent reinforcement. The results indicated: (a) intense auditory stimulation increased the rate of rocking movements in four of six subjects; (b) VI and FR schedules generated curves that are representative of these schedules; (c) DRL schedules decelerated high-rate rocking; (d) DRO schedules eliminated high-rate rocking; (e) noncontigent reinforcement increased variability and resulted in decreased rate of responding. In conclusion, the data support the hypothesis that body-rocking movements in the mentally retarded are an operant and reflect the established characteristics of reinforcement schedules and operant controls.

The study was designed to provide data on the maternal linguistic environments of normal and Down's syndrome children at three levels of language development, as assessed by children's mean length of utterances (MLU). The three MLU levels were 1.00--1.50, 1.75--2.25, and 2.50--3.00, respectively. The subjects were 21 Down's syndrome children and their natural mothers and 21 normal children and their natural mothers. Normal children ranged in chronological age from 20 to 32 months and Down's syndrome children from 3 to 12 years. A one-hour verbal interaction between mother and child was tape recorded at home in a free-play situation. Maternal speech was analyzed using 20 measures related to its output-numerical, lexical, syntactical, semantic-structural, semantic-pragmatic, and language-teaching aspects. Additionally, eight measures of children's speech related to the output-numerical, lexical, syntactical semantic-structural aspects, and to imitativeness of maternal speech were computed as a means of testing the validity of the MLU-matching that forms a basis for this study. Except for the Type-token ratio, which favored Down's syndrome children, normal and Down's syndrome children were not found to differ. In contrast, there were numerous differences between the children in the different aspects of speech considered according to language level. None of the comparisons made of mother's speech to normal and to Down's syndrome children led to differences for any of the three children's language levels studied. It appeared that the maternal linguistic environments of language-learning Down's syndrome and normal children of corresponding MLU were similar in most respects. In contrast, there were numerous differences in mother's speech according to the language level of the children addressed. This confirmed that the expressive language level of the children is a far more powerful factor in influencing maternal speech than whether they are normal or Down's syndrome children. The implications of these findings were related to the delay-difference question in the language development of Down's syndrome children and to various interpretations of the effects of maternal linguistic input for language development and for intervention programs of language enhancement in the Down's syndrome child.

This study investigated the development of nonvocal teaching of reading and writing in severely retarded children. Fourteen subjects were selected who demonstrated limited communication skills, and were randomly placed into two groups. Group A received training procedures utilizing abstract plastic symbols which were arbitrarily assigned to represent specific words. The training program was divided into three phases. Phase I consisted of training left to right sequencing of four color--coded forms; Phase II consisted of training of matching symbols to stimulus pictures; and Phase III consisted of training of fading from symbols to printed words. The subjects completing this training program demonstrated the ability to learn selected reading and writing skills, i.e., they learned to sequence an article, subject noun, auxiliary verb, and verb. They also demonstrated functional semantic comprehension of five nouns and five verbs. Thirteen subjects finished the communication training program in less than four months with a mean training of 7 hours and 55 minutes. This is approximately 2 hours of training a month per subject to learn these skills. The data showed that Group B (rebuses) required fewer trials than Group A (abstract symbols) to meet criterion for Phase II, matching symbols to stimulus pictures. This suggests that Group B subjects may have had a meaningful association for the rebus signs which generalized to stimulus pictures. Group A (abstract symbols) required fewer trials than Group B (rebuse) to meet criterion for Phase 111, matching printed words to stimulus pictures. This indicates that perhaps Group A's training with abstract symbols positively affected learning to read printed words. The success of the visual nonvocal treatment program with the severely retarded is encouraging. Indeed, this is a different and viable approach in teaching communication skills (reading and writing) to the retarded.

Although infant developmental tests have been available for decades, their employment in the analysis of profound developmental retardation has been limited to the prediction of later retardation and the global evaluation of intervention effects. This report summarizes a descriptive study of a sample of profoundly retarded, organically impaired children and adults (IQ less than 15), all of whom were administered the Mental Scale of the Bayley Scales of Infant Development (BSID). One purpose was to promote a more empirically based as well as developmentally oriented treatment of profound retardation, one that bears a closer relationship to the study of normal intellectual development. Another purpose was to examine the reliability of the Mental Scale as tool for assessing behavioral repertoires and for evaluating the effects of intervention with the profoundly retarded. With several qualifications related to test-retest reliability, the Bayley Mental Scale appears capable of serving both descriptive and theoretical functions, and thus of assisting in the organization of new approaches to intervention with profoundly retarded and organically impaired individuals.