OBJECTIVE: This study was undertaken to obtain detailed measurements of
the volume of the brain, using magnetic resonance imaging (MRI), in a
carefully selected group of autistic subjects and comparison subjects.
METHOD: Twenty-two male autistic subjects and 20 male volunteer comparison
subjects were examined with detailed (1.5-mm slices) MRI throughout the
entire brain. Total brain, total brain tissue, and total lateral ventricle
volumes were measured by using manual tracing and automated techniques.
RESULTS: After height and performance IQ were controlled, autistic subjects
had significantly greater total brain, total tissue, and total lateral
ventricle volumes than comparison subjects. CONCLUSIONS: These findings
suggest that male autistic subjects have enlarged brains and that
enlargement is a result of both greater brain tissue volume and greater
lateral ventricle volume.