Functional Brain Connectivity and Memory Impairment in Temporal Lobe Epilepsy (I7.007)
Background Objective: The functional connectivity (FC) in human brain has been implicated both in normal and abnormal brain functions, including epilepsy. In temporal lobe epilepsy (TLE) alteration in FC may involve both seizure generation and co morbid cognitive impairment especially memory dysfunction. This study aimed to investigate FC alteration related to epileptic activities and cognitive functions in TLE patients. Methods: We recruited 99 subjects (left TLE: 36, right TLE: 33, control: 30) who performed EEG, 3 Tesla structural and functional brain MRI, and neuropsychological evaluations. FC based on resting state functional MRI (rs fMRI) data was analyzed using left/right hippocampal region of interests (ROI) Neuropsychologic performance was tested by the Korean version of California Verbal Learning Test (K CVLT) Rey Kim Complex Figure Test (CFT) Controlled Oral Word Association Test (COWAT) Boston naming test (BNT) and Stroop test. Results: Patients with TLE showed lower scores in various neuropsychologic performance compared with controls. K CVLT and BNT were more impaired in left TLE compared with right TLE p =0.025 and p while CFT was more affected in poor seizure control than good control group p =0.017) FC between left/right hippocampus to whole brain showed reduced in TLE, but relatively higher hippocampal connectivity in lesion side (ipsilateral) compared with intact side (contralateral) in both left and right TLE (corrected p .005 and p .005 respectively) More preserved verbal memory scores were associated with higher hippocampal connectivity in ipsilateral as well as contralateral sides (corrected p 001 and p 0.001) which indicates possible compensatory mechanisms in addition to the pathophysiologic changes in these areas. Conclusions: Cognitive impairment in TLE patients can be related to altered functional network involving both ipsilateral and contralateral hippocampal areas as measured by FC analysis based on rs fMRI. These findings support the concept of functional network involvement in TLE not only for epileptogenesis but also for co morbid memory dysfunction. Disclosure: Dr. Jung has nothing to disclose. Dr. Park has nothing to disclose. Dr. Choi has nothing to disclose. Dr. Yoo has nothing to disclose. Dr. Lee has nothing to disclose.