Hemispheric alpha asymmetries and behavioral responses of aphasic and normal subjects for the recall and recognition of active, passive, and negative sentences

The hemispheric alpha asymmetries of a group of normal males, a group of normal females, and a group of aphasic patients (fluent and dysfluent) were examined with electroencephalographic (EEG) techniques under memory conditions of recall and recognition of active, passive, and negative sentences. Aphasic patients, regardless of classification, showed right hemispheric alpha suppression across memory conditions and sentence types. Both normal groups were found to have greater left hemispheric alpha suppression for the recall memory condition and greater right hemispheric alpha suppression for the recognition memory condition (males significantly more than females). The aphasic subjects performed better on recognition tasks compared to recalled tasks and active sentences compared to transformed sentences. Results are discussed as providing evidence of the aphasic subjects' greater dependency on information processing resources of the right hemisphere in the recovery of language function. The findings are also discussed as providing support for a multiple-resources model of information processing.