Memory deficits after resection from left or right anterior temporal lobe in humans: A meta-analytic review

Purpose: Memory deficits in epileptic patients have been found in some, but not all studies assessing the effects of side of seizures and resection from a temporal lobe on cognitive performance. The purpose of this study was to provide a quantitative review of previous studies on this issue. Methods: Based on conventional meta-analytic procedures, we identified 33 studies that assessed verbal and nonverbal memory performance before and after anterior temporal lobectomy. The Logical Memory and Visual Reproduction subtests from the Wechsler Memory Scale were used. These studies were then subjected to two levels of analyses: (a) vote-counting procedure, and (b) effect-size calculations and comparisons. Results: Overall, the data confirmed previous findings that verbal memory tasks are sensitive to left hemisphere dysfunction. The efficacy of a "nonverbal" task for tapping function in the nondominant (right) hemisphere was not confirmed, although a trend supporting this speculation was observed. With regard to the comparison of changes in verbal and nonverbal memory before and after resection from a temporal lobe, a clear trend was observed for decline in verbal memory function after resection from the left, especially significant for immediate verbal recall. A trend for contralateral improvement on non-verbal memory also was observed. The pattern of memory change after resection from the right temporal lobe was less clear. Conclusions: The findings of this study suggest that side of epileptic seizure and surgical resection from a temporal lobe affect verbal memory functions. The relations between the laterality of epileptic seizure, surgical resection from the temporal lobe, and nonverbal memory are to be verified by further research.link_to_subscribed_fulltex

The contribution of neuropsychology to diagnostic assessment in epilepsy

Neuropsychology plays a vital role in the treatment of epilepsy, providing information on the effects of seizures on higher cortical functions through the measurement of behavioral abilities and disabilities. This is accomplished through the design, administration and interpretation of neuropsychological tests, including those used in functional neuroimaging or cortical mapping and in intracarotid anesthetic procedures. The objective of this paper is to define and summarize in some detail the role and methods of neuropsychologists in specialized epilepsy centers. Included are information and recommendations regarding basic ingredients of a thorough neuropsychological assessment in the epilepsy setting, as well as suggestions for an abbreviated alternative exam when needed, with emphasis on functions associated with specific brain regions. The paper is intended for novice and experienced neuropsychologists to enable them to develop or evaluate their current practices, and also for other clinicians, who seek a better understanding of the methodology underlying the neuropsychological input to their work. © 2010 Elsevier Inc.link_to_subscribed_fulltex