Correlation between 1H MRS and memory before and after surgery in mesial temporal lobe epilepsy with hippocampal sclerosis

Purpose: Proton magnetic resonance spectroscopy (H-1 MRS). which can demonstrate neuronal loss and gliosis, may be used as a sensitive tool for lateralization of temporal lobe epilepsy (TLE). Although the correlation between the memory functions and H-1 MRS has been investigated, its predictive value after surgery has not been studied previously. This Study evaluated memory and H-1 MRS values of medically intractable patients with mesial TLE and hippocampal sclerosis (MTLE-HS) before and after selective amygdalohippocampectomy (SAH). Methods: Twenty-two patients underwent memory tests and H-1 MRS investigation before and 6 months after SAH and were compared with nine control subjects. Results: The H-1 MRS scores were found to be significantly low on the pathological side of the patients. Both right-sided H-1 MRS of right TLE and left-sided H-1 MRS values of left TLE patients were correlated only with verbal memory scores. Statistical analysis did not reveal any significance for nonverbal memory scores for both TLE groups on either side, which showed no significant correlation between material specificity and H-1 MRS findings. Conversely, regression analyses demonstrated that high right- and low left-sided H-1 MRS values obtained before surgery may predict a decline in verbal learning scores after surgery. Conclusions: H-1 MRS can be considered as a useful tool to determine the lateralization in patients with MTLE-HS before the Surgery. Although only a weak relation exists between the MRS values and memory scores, presurgical MRS scores may be predictive for a possible deterioration in verbal memory after surgery. However, further studies with higher numbers of cases are needed for confirmation of the results.