Different Profiles of Verbal and Nonverbal Auditory Impairment in Cortical and Subcortical Lesions

A B S T R A C T Introduction:We investigated differential role of cortical and subcortical regions in verbal and non-verbal sound processing in ten patients who were native speakers of Persian with unilateral cortical and/or unilateral and bilateral subcortical lesions and 40 normal speakers as control subjects. Methods: The verbal tasks included monosyllabic, disyllabic dichotic and diotic tasks, and nonverbal tasks were semantic, asemantic recognition and sound localization. Results: Different profiles of ear extinction and hemispatial neglect was observed in our Left Hemisphere-Damaged (LHD) patients. Right Hemisphere-Damaged (RHD) patients with basal ganglia lesions showed mild hemi-spatial inattention of the ipsilesional and contralesional hemispace. LHD patients showed deficient performance in sound localization, but no evidence of significant impairment in sound localization was found in RHD patients except one. The patients with basal ganglia lesions irrespective of lesion side had impaired performance in semantic recognition. The results are suggestive of a network consisting of left and right basal ganglia and left cortical regions for non-verbal sound recognition. Discussion: The results also indicate a different role for left basal ganglia in sound object segregation versus sound localization.