BIMANUAL COORDINATION WITH AGING - IMPLICATIONS FOR INTERHEMISPHERIC-TRANSFER

With only a few exceptions, several studies examining the size of the corpus callosum have recently reported decreases in callosal area or length, particularly in the anterior region, with age. To assess whether these possible structural changes are reflected in reduced interhemispheric transfer, we used a modified version of Preilowski's (1972) bimanual coordination task (BCT). The task, previously shown to be sensitive to changes in callosal transfer efficiency, particularly in the anterior region, involved bimanual control of the movement of a drawing point to create angled lines. A group of healthy elderly people (60-85 years) gave significantly overall poorer performance than younger participants (19-29 years). The age-related deficit increased in greater proportion for those lines requiring asymmetric hand control without visual feedback. Because these latter conditions are presumed to place the greatest demands on callosal transfer, the results are consistent with reduced interhemispheric transfer efficiency with aging, probably in the anterior callosum. No consistent gender differences were found. The possibility of using this, and similar methods, to assess general neurocognitive changes with age are discussed.