Dichotic listening in aphasics: response to Niccum and Speaks.

Since the dichotic listening technique was first described (Broadbent, 1954; Kimura, 1961), researchers have been interested in its ability to document hemispheric dominance for language and other functions in a noninvasive fashion. Numerous articles have been published using normal healthy subjects as well as others using patients who have suffered neurological disease or damage. Much controversy has been generated over the use of dichotic listening in the latter population, however, since unilateral brain lesions might be expected to alter normal perception. This paper responds to one recently published by Niccum and Speaks (1991) that attempted to explain why a lesion effect, and not hemispheric reorganization, is the best explanation for findings of left-ear advantage in recovering aphasics.