Sound localization in egocentric space following hemispheric lesions

In this paper the performance of patients with unilateral hemispheric lesions (n = 10 with right brain damage; n = 10 with left brain damage) on a free-field sound localization task was contrasted with that of healthy controls (n = 10). Sound stimuli were presented binaurally in the horizontal plane from eight loudspeakers set at azimuths between -105 degrees and +105 degrees. Whereas performance of both patient groups was generally less accurate than controls, no evidence suggested that this was specific to the contralateral hemisphere. The results indicate that both hemispheres play a role in sound localization, with systematic directional errors made towards the ipsilateral hemifield following unilateral lesions. Furthermore, particular location difficulties at pericentral positions (+15 degrees and -15 degrees) following right hemisphere damage, may indicate a specific function for the right hemisphere in determining personal frames of spatial reference within pericentral space.