Lateralization of activity associated with language function using magnetoencephalography - a reliability study

This study was conducted to investigate the reliability of magnetoencephalography in lateralizing and localizing brain activity associated with receptive language function. Sixteen right-handed adults with no history of neurologic disorder engaged in a continuous recognition memory task for visually presented words in two separate sessions. The magnetic flux normal to the scalp surface was measured with a whole-head neuromagnetometer during task performance. Using the total number of acceptable activity sources as an index, overall activation was greater in the left compared with the right hemisphere for all 16 subjects in both sessions. Sources of activity were consistently found in the temporoparietal areas of the left hemisphere in all subjects. Moreover, clusters of activity sources in this region either overlapped spatially or were found in close proximity across sessions. Medial and basal temporal lobe activity was also observed in most subjects during at least one session, and tended to be lateralized to left hemisphere. These results suggest that magnetoencephalography is a promising tool for determination of cerebral dominance for language and localization of temporal lobe language areas.