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.

Normal movement reading in Asperger subjects.

Patients with autism and Asperger syndrome (AS) are impaired in mindreading and imitation skills. One possibility would be that their 'mirror neuron' system, which matches action execution and observation, does not function properly. To test this hypothesis we compared action-viewing related motor cortex functions in an AS group (one autistic and four AS subjects) and eight control subjects. In both groups viewing hand actions modified the neuromagnetic approximately 20 Hz oscillatory activity in the primary motor cortex to the same extent. Thus impaired mindreading and imitation skills found in AS and autism do not seem to result from dysfunction of the motor cortex part of the action execution/observation system.