Memory for the past after temporal lobectomy: impact of epilepsy and cognitive variables

A few previous studies have revealed impairments in remote memory in patients with temporal lobe epilepsy, but many questions about the importance of lesion side, type of material, seizure history and deficits in other aspects of cognitive functions remain unanswered. In this study, patients who had undergone unilateral (15 right and 15 left) temporal lobectomy (TL) for the relief of epilepsy and 15 control subjects completed a range of public and autobiographical memory tests. Deficits in recall and recognition of details related to past famous world events were observed for both left and right TL groups. In addition, the left TL group showed impaired retrieval of famous names and TL patients as a group generated significantly fewer names of people from their own past. Current seizure- and medication-status influenced performance on a few measures, but duration of epilepsy and age of onset had no significant impact. Underlying cognitive deficits (especially naming ability) contributed to, but could not completely explain difficulties remembering the past. In particular, deficits in the ability to retrieve highly specific information learned in the past, such as names of famous people or details about famous events, remained evident in analyses that controlled for the impact of related cognitive skills.