Authors
Holttum JR, Minshew NJ, Sanders RS, Phillips NE.
Institution
Department of Psychiatry, University of Pittsburgh School of Medicine,
PA.
Title
Magnetic resonance imaging of the posterior fossa in autism.
Source
Biol Psychiatry 1992 Dec 15;32(12):1091-101
Abstract
The brainstem-cerebellar circuitry has been implicated in the pathophysiology
of autism for several decades. Recent magnetic resonance imaging (MRI) studies
of the posterior fossa have reported various abnormalities, the most noteworthy
of which has been selective hypoplasia of the neocerebellar vermis. However,
these initial MRI studies are limited by problems in both subject and control
selection. The present study was undertaken to further investigate these
MRI findings and the role of the cerebellum in autism, taking into consideration
these methodologic issues. Eighteen high-functioning autistic subjects were
recruited and matched with 18 normal controls on the basis of age, gender,
IQ, race and socioeconomic status (SES). The midsagittal areas of the cerebellar
vermis, vermal lobes, and the fourth ventricle were measured on 3 mm contiguous
magnetic resonance images. Mean areas and standard deviations were comparable
for all regions of interest and no statistically significant between-group
differences were found. These negative findings argue against theories of
autism based on gross structural abnormalities of the cerebellum. Previous
reports of posterior fossa abnormalities may be related to technical and
methodological factors, based on comparison of extant literature and recently
available normative data.