Quantitative magnetic resonance image analysis of the cerebellum in macrocephalic and normocephalic children and adults with autism
A detailed morphometric analysis of the cerebellum in autism with and without macrocephaly. Four subject groups (N = 65; male; IQs [greater-than-or-equal] 65; age 7 to 26 years) were studied with quantitative MRI; normocephalic and macrocephalic individuals with autism without mental retardation were compared to normocephalic and benign macrocephalic typically developing individuals. Total cerebellum volumes and surface areas of four lobular midsagittal groups were measured. Independent t-tests between autism and control subjects matched for head size revealed no significant differences. Multivariate analyses of variance were also performed, using the diagnostic group as the fixed factor, cerebellar measures as the dependent variables and total intracranial volume, total brain volume, age, verbal IQ, and performance IQ as covariates. No significant differences were found; however, a trend was noted in which macrocephalic individuals with autism consistently exhibited slightly smaller cerebellar volume or surface area when compared to individuals with benign macrocephaly. In autism, with and without macrocephaly, cerebellar structures were found to be proportional to head size and did not differ from typically developing subjects. (JINS, 2008, 14, 401–413.)(Received March 29 2007)
(Revised January 23 2008)
(Accepted January 29 2008)
Key Words: Neuroimaging; Autism; Cerebellar; Brain volumes; Head size.
c1 Correspondence and reprint requests to: Erin D. Bigler, Ph.D., Departments of Psychology and Neuroscience, 1001 SWKT, Brigham Young University, Provo, Utah 84602. E-mail: [email protected]