Differential perseverations in verbal retrieval related to anterior and posterior left hemisphere lesions.

Sixty-two patients with focal cerebral lesions and 11 control patients were examined using alternating tasks of learning, generation, and recall of words beginning with "K." The results supported the hypothesis that "recurrent" and "stuck-in-set" varieties of perserveration are related to posterior and anterior left hemisphere lesions, respectively. Patients with left posterior lesions usually failed to suppress the expression of previously generated words in the subsequent generation task, whereas patients with left anterior lesions stated a greater number of new (incorrect) words in the recall of previously learned words, presumed to indicate stuck-in-set perseveration of the previous generation performance.