Hemispheric alpha asymmetries of aphasic and normal subjects: Results from recognition and recall tasks using visually presented words of high and low imagery

Abstract

Hemispheric alpha asymmetries of normal males, normal females, and male aphasics were observed from anterior and posterior placement sites for recall and recognition of visually presented high and low imagery words, and during resting conditions. No significant differences were observed during the resting conditions between groups. However, during visual presentation of words the aphasics demonstrated significantly less alpha in the right hemisphere, while no differences were observed for the normal subjects. Both fluent and non-fluent aphasics demonstrated right hemisphere alpha suppression across stimulus and task conditions. The non-fluent aphasics demonstrated lower overall alpha power levels across hemispheres than did the fluent aphasics. Results are discussed relative to the aphasics becoming more dependent upon the processing resources of the intact right hemisphere during the course of language recovery.