Classification and recall of pictures after unilateral frontal or temporal lobectomy.

Classification and recall of pictures of familiar objects were studied in 21 normal control subjects and 75 patients with unilateral cerebral excisions. The patients with frontal-lobe excisions were impaired at categorizing the pictures and at recalling the objects depicted. Left and right temporal-lobe groups performed the sorting task normally, but the left temporal-lobe groups were impaired at recalling picture names. The right temporal-lobe groups were unimpaired. A negative correlation between the number of items uncategorized and the number recalled was found in the right frontal-lobe group but not in the left, who were impaired also at recalling the items that they had classified correctly. It is concluded that impaired categorization played a major role in determining the recall deficits in the right frontal-lobe group but not in the left, whose impaired recall may also be due to defective retrieval. The poor recall of the left temporal-lobe groups is thought instead to depend on abnormally rapid forgetting.