Early speculation that the right hemisphere assumes control over residual language function in many aphasics has received tentative support from recent empirical studies. We shall attempt a more definitive test by applying, to cross-sectionally and longitudinally studied left hemisphere damaged aphasics, paired verbal and hemisphere-neutral laterality paradigms, specifically selected to deconfound (i) """"""""right-control"""""""" from (ii) disconnection of the left hemisphere from information flow and (iii) nonspecific shifts in laterality due to lesion-induced activation imbalance between the hemispheres. Dichotic and free field listening and visual half-field laterality paradigms, lateral gaze and induced lateral orientation and interference between concurrent speech and manual rhythms are predicted to yield converging lateral biases on patients with right control versus left control. We shall retrospectively search for subject variables that predict side of control. We shall further determine whether right control is maintained throughout language recovery. Finally, we will test the prediction that right hemisphere test performance will be impaired in right-control patients and only when the stimulus material is verbally codable.
