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

This study was conducted to investigate the reliability of magnetoencephalo graphy in lateralizing and localizing brain activity associated with recept ive language function. Sixteen right-handed adults with no history of neuro logic 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 in dex, overall activation was greater in the left compared with the right hem isphere for all 16 subjects in both sessions. Sources of activity were cons istently found in the temporoparietal areas of the left hemisphere in all s ubjects. Moreover, clusters of activity sources in this region either overl apped spatially or were found in close proximity across sessions. Medial an d 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 determi nation of cerebral dominance for language and localization of temporal lobe language areas.