Neuropsychological test performance and MEG-based brain lateralization: sex differences.

Magnetoencephalographic (MEG) auditory evoked fields (EF) were recorded from left and right hemispheres of 9 normal males and 12 normal females. Source location of the 100 ms latency component (M100) was localized to superior temporal lobes bilaterally using an inverse solution algorithm. All subjects also were administered the Wechsler block design and visual reproduction subtests, and the California Verbal Learning Test (CVLT). M100 source locations demonstrated significant sex differences in interhemispheric asymmetry. Males had source locations further anterior than females, with the differences most pronounced in the right hemisphere. Expected sex differences were found in neuropsychological test performance, with males performing better on block design ad visual reproduction, and females performing better on the CVLT. Across both sexes, block design scores correlated significantly with right hemisphere M100 location, with more anterior source locations associated with better performance. CVLT scores were negatively correlated with right hemisphere M100 source locations. These findings suggest MEG-based measures of interhemispheric asymmetry may be related to specific neuropsychological test performance measures.