Gesture fluency after focal cortical lesions.

Patients with unilateral cortical excisions and normal control subjects were given two 'gesture fluency' tasks: one assessed their ability to generate novel finger positions, and the other their ability to produce meaningful gestures. Patients with left-frontal lesions were impaired on both tasks, and patients with right-frontal lesions were impaired on the latter. The deficit after right-frontal lesions appeared to be associated with involvement of ventro-lateral or orbital cortex, whereas there was no evidence for localization within the left frontal lobe. The results extend previous findings of deficits after frontal lesions on tests of word and design fluency.