Psychological effects of stereotaxic operations for the relief of parkinsonian symptoms.
Subcortical stereotaxic operations for the relief of Parkinsonian symptoms provide an opportunity for the study of psychological changes following lesions in these nuclei.

Fifty-six patients have been tested before and soon after unilateral operation aimed at the globus pallidus or the ventrolateral nucleus of the thalamus. The changes observed are losses on verbal tests following operations on the left and on “performance” tests following those on the right. These results are similar to the types of impairment found with cortical lesions in the same hemispheres.

The significance of these losses, and of certain gains in scores, is discussed.