Failure to manipulate objects secondary to active touch disturbance.

A peculiar type of sensori-motor disturbance consequent to a lesion in the contralateral postcentral gyrus was reported. The symptom was characterized by motor clumsiness of the left hand without loss of strength and with preserved finger movements on visual imitation. Motor difficulty was most marked when the patient had to manipulate an object. The analysis of the patient's behavior and of his sensory deficits suggests that the basis of the clumsiness was a deficit in active touch perception.