The Role of Abnormal Hemispheric Specialization in Autism

Abstract

In 1974 Rutter speculated that left hemisphere dysfunction may play a significant role in autistic symptomology. He based this supposition on the fact that autistic children often exhibit an uneven pattern of cognitive abilities suggestive of left hemisphere dysfunction. When the autistic child shows peak skills, they are usually in areas of functioning traditionally associated with the right hemisphere, such as visuospatial abilities and pattern recognition. In contrast, the autistic child’s most pronounced deficiencies are in areas of functioning traditionally associated with the left hemisphere, such as the use of spoken and gestural language. Around the same time, Ricks and Wing (1975) made a similar speculation based on their finding that autistic children had specific difficulties in the use of symbols. In the last decade, several investigators have explored the role of abnormal hemisphere development in the syndrome of autism. Indeed, there now exist numerous studies of many aspects of brain functioning in autistic children. It is clear from these studies that, while left hemisphere dysfunction may play a role in autistic symptomology, it is only one piece in a complex and nonunitary neurological basis of autism. However, since many of the core symptoms of autism, such as impairments in the use of symbols, may involve dysfunction at the cortical level, it is important that this aspect of brain functioning be explored fully.