Relationship between resting state functional magnetic resonance imaging and memory function in mesial temporal lobe epilepsy

Object: To study memory impairment mechanisms of the medial temporal lobe epilepsy (MTLE) by analyzing the functional connectivity (FC) through resting state functional magnetic resonance imaging (rs-fMRI). Methods: Rs-fMRI data were acquired from 13 patients with left MTLE and 11 patients with right MTLE. Another 13 healthy volunteers were selected as controls. The altered FC pattern between the unilateral hippocampus and other regions of the brain in MTLE patients was compared to that of the normal control group. Then the correlation between the strength of FC and the clinical memory scale scores in patients with MTLE was determined. Results: The scores of the following check points of MTLE patients including point to memory, recognition of nonsense figure, associative learning, the image free recall, portrait characteristic recall and memory quotient were significantly lower than those in the normal group (all P < 0.05). The scores of point to memory and recognition of nonsense figure were different between R-MTLE and L-MTLE patients. Different correlations between the strength of FC and the clinical memory scale scores were detected between R-MTLE and L-MTLE patients. Conclusions: The memory function of patients with MTLE was impaired. Patients with L-MTLE showed lower score on pure verbal memory test and those with R-MTLE showed weaker performance on pure visual memory test. Patients with MTLE showed extensive abnormal FC between hippocampus and particular encephalic regions. (C) 2016 Elsevier B.V. All rights reserved.