Hemispheric asymmetries, fourth ventricular size, and cerebellar morphology in autism.

Hemispheric asymmetries, fourth ventricular size, and cerebellar morphology were examined in 15 healthy men, aged 18 to 39 years, with documented childhood diagnoses of infantile autism, and in 20 healthy age- and sex-matched controls using computerized transverse axial tomography (CT). Nine patients were of approximately average intelligence, 3 showed specific language impairments, and 3 were mentally retarded. No significant group differences were seen in the distributions of frontal or posterior asymmetries of width or petalia. No subject showed evidence of cerebellar atrophy or an enlarged fourth ventricle. These results fail to support a hypothesis of unusual hemispheric asymmetry or macroscopic abnormalities of the posterior fossa in autism.