Sensory-specific and fractional disorders of recent memory in man. II. Unilateral loss of tactile recent memory.

Three patients were found to have unilateral tactile recent memory loss on examination. In two patients the loss occurred in the right hand and was accompanied by a disorder of verbal recent memory; in the third patient the loss occurred in the left hand and was not accompanied by any other disturbance in recent memory. An acute unilateral lesion, either structural or functional, in the medial temporal lobe contralateral to the tactile recent memory disturbance was the common denominator in all three cases. The proper methods for diagnosing a unilateral tactile disturbance of recent memory and other forms of fractional disorders of recent memory are discussed. Based on computerized tomography scans and behavioral and anatomical data in man and monkey, an anatomical explanation is offered to account for the syndromes of right and left unilateral tactile recent memory loss. The possible existence of other forms of fractional disturbances of recent memory and the role of the cerebral commissures in recent memory functions are discussed.