Age and responding-hand related changes in performance of neurologically normal subjects on the line-bisection and chimeric-faces tasks

This study investigated age and responding-hand (left, right, and bimanual) related changes in visuospatial attention. Two tasks were completed by 107 neurologically normal right-handed subjects ranging in age from 5 to 70 years and distributed across four age groups. Task-specific differences between groups were apparent. In the line-bisection task, the younger and older groups displayed symmetrical neglect while the young and middle groups displayed pseudoneglect. In the chimeric-faces task the leftward bias was less pronounced in the older group and more susceptible to responding-hand effects in the middle and older groups. Whilst results, especially those of the bimanual method, provided strong support for an activation model, they imposed an age limitation on its appropriateness as an explanation for performance on the chimeric-faces task. Results are discussed as reflecting changes in the corpus callosum and right hemisphere.