A quantitative controlled MRI study of the brain in 28 persons with Asperger syndrome.

BACKGROUND As structural brain abnormalities have been reported in infantile autism, the aim of this study was to determine whether such findings also exist in Asperger Syndrome (AS). METHODS The diagnosis of Asperger Syndrome was based on the criteria in ICD-10 and DSM-IV. Brain magnetic resonance imaging (MRI) was performed with a 1.5 T imager. T2-weighted axial and coronal slices and T1-weighted three dimensional sagittal slices were obtained and visual and quantitative analysis were performed. SUBJECTS There were 28 Asperger individuals, 17 children and adolescents (age 6-19 years, mean 12.4 years), 11 adults (age 20-60 years, mean 37. 9 years) and 28 healthy age and gender matched controls. RESULTS Mild inconsistent alterations were detected in 13/28 of the individuals with Asperger Syndrome compared to 6/23 in the comparable controls. There were no differences between the right and left hemispheres, nor was there any abnormality in terms of myelination or migration. The anterior-posterior diameters of the mesencephalon were statistically significantly shorter in the Asperger syndrome individuals than in the controls. CONCLUSIONS No consistent focal brain abnormalities for Asperger Syndrome were detected. The reduced diameters of the mesencephalon in the Asperger group support the hypothesis that the mesencephalon may be involved in the pathogenesis of Asperger Syndrome.