Explicit and Implicit Memory in Children and Adults with Temporal-Lobe Epilepsy
Abstract number :
2.245
Submission category :
Year :
2000
Submission ID :
2563
Source :
www.aesnet.org
Presentation date :
12/2/2000 12:00:00 AM
Published date :
Dec 1, 2000, 06:00 AM
Authors :
Rebecca L Billingsley, Mary Lou Smith, Mary Pat McAndrews, Univ of Toronto and The Hosp for Sick Children, Toronto, ON, Canada; Univ of Toronto and The Toronto Western Hosp, Toronto, ON, Canada.
RATIONALE: Numerous studies of temporal-lobe epilepsy (TLE) suggest that explicit memory depends on intact medial temporal lobes. Neural correlates of perceptual and conceptual implicit memory, however, are less clear. Children and adults with TLE were tested on implicit and explicit memory tests. If dominant temporal cortex is essential for normal conceptual implicit memory performance, left but not right TLE patients should show conceptual priming deficits. If implicit memory is supported by widespread cortical areas, higher seizure frequency should result in worse performance on perceptual and conceptual tests, as nociferous effects are more likely in regions beyond the seizure focus. METHODS: Left (10 pre- and 13 post-operative) and right (8 pre- and 11 post-operative) TLE patients were matched for age and sex with controls. Most of the patients had confirmed hippocampal damage (69% in each group). Participants read or generated words under incidental encoding. Following a filled, 20-minute interval, they were given implicit conceptual generation and perceptual identification tests. Recall and recognition tests followed the implicit tests. RESULTS: No group differences were found on the implicit memory tests. Both TLE groups showed impaired recall performance, but only the left TLE group showed recognition deficits. Higher seizure frequency in the pre-operative left TLE group was associated with worse recall scores, but neither seizure frequency nor operative status influenced priming performance. Children and adults with TLE showed similar implicit and explicit memory performance. CONCLUSIONS: Neither medial nor lateral temporal dysfunction appears to influence conceptual or perceptual implicit memory. Important methodological differences likely account for the discrepancy between this study and Blaxton's (1992) report of impaired conceptual priming in left TLE. These data bolster evidence for memory systems that can be dissociated neurobiologically. Conceptual and perceptual implicit memory are more resistant to impairment than recall and recognition in TLE. Reference Blaxton, T.A. (1992). Memory and Cognition, 20, 549-562.