Transient and persistent right ear extinction in dichotic listening: subcortical lesions.

Nine patients with aphasia had right ear extinction in dichotic listening to words in the first month after an ischemic stroke; they were reassessed after 3 months. Four showed complete recovery from the right ear extinction; in five, the abnormality persisted. In those who recovered, CT revealed a subcortical lesion lateral to the frontal horn of the lateral ventricle without a lesion of Heschl's gyrus or geniculo-temporal pathways; a lesion in those structures was found in patients who did not recover. As reported for subcortical aphasia, a subcortical mechanism may explain contralateral ear extinction in dichotic listening.