Subcortical neglect: quantitation, anatomy, and recovery.

Fifteen patients with right hemispheric subcortical infarcts localized by CT or MRI were evaluated with a neglect testing battery. Trimodal extinction was present in one case, visual extinction in three, tactile in three, and auditory in six. Although frequent (10 cases), hemispatial neglect was rarely severe (3 cases). Three cases recovered completely. Large posterior internal capsule lesions were associated with more frequent impairment on a cancellation test. The probable mechanism of hemispatial neglect was attentional in one case and intentional in six. Visual and auditory extinction is explained by striatonigral mechanisms. Although subcortical structures participate in attentional and intentional behavior, cortical structures can substitute for their functions.