The purpose of this study was to investigate the association between extracellular basal hippocampal glutamate levels and cognitive function in epileptic patients. We used the zero-flow microdialysis method to measure the extracellular concentrations of glutamate in the epileptogenic and non-epileptogenic hippocampus of 23 awake epileptic patients during the interictal period. All patients underwent extensive neuropsychological testing to assess cognitive functioning prior to probe implantation. Basal glutamate levels in the epileptogenic hippocampus were significantly higher than the non-epileptogenic hippocampus (mean, 11.96 micromolar (µM) versus 2.92 µM, respectively). Elevated basal glutamate levels in the epileptogenic hippocampus correlated with decreased scores on the Verbal Selective Reminding Test (V-SRT) (R[exponent]2 = 0.36, p = 0.0244). When controlling for MRI-detected hippocampal atrophy within epileptogenic regions, elevated basal glutamate levels within atrophic hippocampus correlated with decreased cognitive functioning measured by both the V-SRT (R[exponent]2 = 0.7764, p = 0.0204) and Performance Intelligence Quotient (PIQ) (R[exponent]2 = 0.7324, p = 0.0297), but not within non-atrophic hippocampus (V-SRT: R2 = 0.1013, p = 0.4424; PIQ: R[exponent]2 = 0.2303, p = 0.2288). These data suggest that elevated basal glutamate levels in the epileptogenic hippocampus may be implicated in the pathogenesis of hippocampal atrophy and may contribute to impaired cognitive functioning involving verbal memory and visual-spatial skills in patients with temporal lobe epilepsy.
| Identifer | oai:union.ndltd.org:YALE_med/oai:ymtdl.med.yale.edu:etd-06262006-125510 |
| Date | 03 November 2006 |
| Creators | Buragas, Michele Sophia |
| Contributors | Idil Cavus |
| Publisher | Yale University |
| Source Sets | Yale Medical student MD Thesis |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://ymtdl.med.yale.edu/theses/available/etd-06262006-125510/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Yale School of Medicine or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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