Environmental sound recognition after unilateral subcortical lesions.

Nonverbal environmental sound recognition was investigated in 24 subjects with unilateral subcortical lesions and 20 age-matched normal controls. All patients incurred putaminal hemorrhage at least three months before examination, and had a cystic lesion under the insula on CT or MRI at the time of evaluation. A mild impairment was found in association with extensive damage to the lateral and ventral portions of the putamen and the adjacent white matter in either the right or left hemisphere. Degree of impairment and type of error did not differ significantly between the sides of lesions. These observations and a review of literature suggest that the impairment of environmental sound recognition may arise with a unilateral subcortical lesion disrupting the geniculo-auditory association cortex projection fibers.