Auditory extinction: the effect of stimulus similarity and task requirements.

Auditory extinction was examined in six patients with right hemisphere lesions, using an auditory double simultaneous stimulation task using letters spoken in male and female voices. Patients had to detect where the stimuli were located, and identify either the letter or the voice (the task-relevant dimension). Auditory extinction was greatest when the two stimuli were the same on the task-relevant dimension, paralleling previous studies of visual extinction. Furthermore, we found that errors of omission were much less frequent in the contralesional field if the patients were not required to report both identity and the location of stimuli. These results are consistent with the notion that auditory extinction may be due in part to a failure to bind together identity and location.