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March 1987

Abnormal Neuroanatomy in a Nonretarded Person With AutismUnusual Findings With Magnetic Resonance Imaging

Author Affiliations

From the Neuropsychology Research Laboratory, Children's Hospital Research Center, San Diego (Dr Courchesne and Mrs Yeung-Courchesne); the Departments of Neurosciences (Dr Courchesne), Radiology (Drs Hesselink and Jernigan), and Psychiatry (Dr Jernigan), University of California at San Diego School of Medicine, La; Jolla; and the Psychiatry Department, Veterans Administration Medical Center, San Diego (Dr Jernigan).

Arch Neurol. 1987;44(3):335-341. doi:10.1001/archneur.1987.00520150073028

• Recent studies of infantile autism using computed tomographic scanning emphasized the importance of studying cases of classic autism (Kanner's syndrome) without complicating conditions such as mental retardation. Computed tomographic scan studies of such patients reported no evidence of anatomical abnormalities of cerebral hemi-spheres or of subcortical structures, which are defined by landmarks such as the lateral ventricles and lentiform nuclei. Examination of the cerebellum was not mentioned. The most recent postmortem neuropathologic study reported significant cerebellar abnormality, but the study was of a severely retarded autistic individual. Using magnetic resonance imaging, we have found in vivo evidence of a significant and unusual cerebellar malformation in a person with the classic form of autism uncomplicated by mental retardation (current nonverbal IQ = 112), epilepsy, history of drug use, postnatal trauma, or disease. The finding showed hypoplasia of the declive, folium, and tuber in posterior vermis, but not of the anterior vermis, and hypoplasia of only the medial aspect of each cerebellar hemisphere. The right posterior cerebral hemisphere also showed pathologic findings.