The Lateralization and Localization of Memory and Neurocognitive Functioning in Patients with Temporal Lobe Epilepsy / 대한간질학회지

ABSTRACT

PURPOSE: Material-specific memory deficits (laterality effects) are frequently observed in patients with temporal lobe epilepsy (TLE), and yet the different functional roles of temporal cortical vs. mesial structures remain unclear. This study aimed to examine the lateralization and localization of memory and other neurocognitive functioning in patients with TLE. METHODS: Sixty-nine patients with lesional TLE participated. Subjects were categorized in terms of lesion laterality (left, n=34; right, n=35) and intratemporal location (mesial, n=50; lateral, n=19). Neurocognitive tests, including verbal memory, visual memory, general intelligence, attention, working memory and executive function, were tested. RESULTS: Left TLE patients showed significantly higher visual than verbal memory capacity, whereas right TLE patients showed significantly better verbal than visual memory capacity. There were no differences between mesial TLE and lateral TLE groups on any other memory tasks. Mesial TLE patients showed significantly lower working memory and executive function compared with lateral TLE patients. CONCLUSIONS: Selective verbal or visual memory deficits that are dependent on side of seizure foci were apparent in this study. The different functional roles of temporal cortical vs. mesial structures in memory process (i.e. aquisition/working memory vs. long-term consolidation) were not clear, but rather mesial temporal lobe damage was found to be associated with working memory deficit. It may be explained in part by epileptogenic activity propagating from temporolateral to mesial structures and vice versa.