Retrograde amnesia following unilateral temporal lobectomy.

Remote memory performance was assessed in a carefully matched sample of temporal lobectomy subjects and normal controls. Left temporal lobectomy subjects exhibited a consistent pattern of remote memory disturbance. Right temporal lobectomy subjects performed at the same level as normal controls. The pattern of impairment observed in left temporal lobectomy subjects was characterized by deficits in recall of chronological information from the past decade and extended to deficits in recall in some aspects of factual knowledge. The disorder could not be attributed solely to language deficits and was at least as severe as accompanying deficits in recent memory. These findings suggest that the left medial temporal region may play a significant role in recall of remote information in addition to its role in recent memory functions.