Dichotic ear preference for C-V-C words in Wernicke's and Broca's aphasias

A dichotic listening task was administered to subjects with a relatively distinct Broca's aphasia, subjects with a relatively distinct Wernicke's aphasia, and normal subjects. The dichotic stimuli consisted of C-V-C words differing in initial consonant only. Subjects were instructed to respond only to the stimulus of which they were most sure by pointing to a picture representing the dichotic stimuli or foils. while normal subjects demonstrated the usual right ear effect, both the Broca's and Wernicke's aphasia groups demonstrated left ear effects. One salient explanation for these results was that any severe defect in the language systems of the left hemisphere affects the way that the left hemisphere processes linguistic information. It was postulated that left ear stimuli, which arrive at the left hemisphere later, disrupt the processing of right ear stimuli in subjects with aphasia. However, a more definitive explanation requires further research.