Developmental auditory agnosia in retarded adolescents: A preliminary investigation

Four mentally retarded adolescents who showed little or no expressive or receptive language were given a series of tests to determine if they could respond to meaningful nonlinguistic sounds. The tests required the subjects to respond to sounds on the basis of meaning by classifying the sounds according to the objects which produced them, i.e., the sound sources. The results show that the subject could not classify the sounds on the basis of their source although they could discriminate between them. These results are in contrast to the near perfect classification by another retarded subject who lacked speech due to a motor disorder but, nevertheless, showed good understanding of language. The finding that some nonverbal children have difficulty in responding to the meaning of nonlinguistic sounds suggests the possibility that the failure of these children to develop language may have been due to an agnosia not unlike that found in adult stroke patients.