The cerebellum is one of the most consistent sites of neuroanatomic abnormality in autism, but the motor consequences of the possible cerebellar dysfunction are poorly documented. The purpose of the present study was to examine individuals with autism, mental retardation, and normal development, in their performance on tasks sensitive to cerebellar function. Forty-two children, aged 7.7 to 12.8 years, were tested in nine cerebellar tests. Fourteen of them were persons with autism, fourteen were mentally retarded with IQs comparable to those of the autistic group and the other fourteen were typically developing children. The three groups were age- and sex-matched. Children with autism presented hypotonia, and their performance was significantly lower than that of typical children for most cerebellar tasks, notably those requiring fine motor skill and balance. They performed worse than children with mental retardation in half of the tasks. In contrast, there was no significant difference between the three groups in tasks independent of cerebellar function. This pilot study supports the hypothesis of cerebellar dysfunction in autism and calls for further research.
KEYWORDS: cerebellum, autism, motor tasks.