Correlation between ¹H MRS and Memory before and after Surgery in Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis

Abstract

Summary: Purpose: Proton magnetic resonance spectroscopy (1H 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 1H MRS has been investigated, its predictive value after surgery has not been studied previously. This study evaluated memory and 1H 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 1H MRS investigation before and 6 months after SAH and were compared with nine control subjects. Results: The 1H MRS scores were found to be significantly low on the pathological side of the patients. Both right‐sided 1H MRS of right TLE and left‐sided 1H 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 1H MRS findings. Conversely, regression analyses demonstrated that high right‐ and low left‐sided 1H MRS values obtained before surgery may predict a decline in verbal learning scores after surgery. Conclusions: 1H 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.

Correlation between calbindin expression in granule cells of the resected hippocampal dentate gyrus and verbal memory in temporal lobe epilepsy

“…An event-related potential study showed the involvement of hippocampal formation and amygdala during verbal learning and memory, and amnesic patients with hippocampal lesion present greater impairment in declarative than in procedural memory [64,65]. In the literature, left HS was correlated with deficiency of verbal, right HS with impairment of visuo-spatial memory, and the severity of memory deficits was related to the degree of HS detected with MRI or 1 H MRS [41][42][43]. In addition, the degree of pyramidal cell loss in Ammon's horn and loss of hilar neurons and granule cells of the dentate gyrus correlated to memory impairments [44,45,[47][48][49].…”

“…In addition, deficiency of verbal memory in left HS and deficiency of visual memory in right HS were observed in patients with early-onset, long-term duration and highfrequency of seizures [42]. Proton magnetic resonance spectroscopy ( 1 H MRS), which is assumed to be suitable for providing information about neuronal loss and gliosis, revealed correlation between 1 H MRS values and verbal memory scores [43]. Postoperative histological studies showed that pyramidal cell loss in the removed hippocampal formation significantly correlated with preoperatively detected memory impairments of patients [44][45][46][47][48][49].…”

Predicting Memory Decline Following Epilepsy Surgery: A Multivariate Approach

“…Data from baseline neuropsychological tests (Chelune et al, 1991; Davies et al, 1998; Jokeit et al, 1997) and the intracarotid amobarbital procedure (IAP) (Bell et al, 2000; Chiaravalloti and Glosser, 2001; Kneebone et al, 1995; Loring et al, 1990) have been found to predict some of the variance in postoperative memory function. Similarly, preoperative measures of hippocampal integrity including direct recordings from hippocampal neurons (Cameron et al, 2001), 1H MRS (Hanoglu et al, 2004) and hippocampal volumes and T2 relaxation times derived from preoperative MRI studies have been shown to predict some aspects of postoperative memory function (Baxendale et al, 1998; Wendel et al, 2001). More recently, a number of functional imaging paradigms have shown some promise in the prediction of both postoperative decline in both visual (Janszky et al, 2005) and verbal (Richardson et al, 2004) memory skills.…”

Treatment Strategy for the Patient with Hippocampal Sclerosis Who Failed to the First Antiepileptic Drug

“…There are progressive behavioral changes including increasing memory deficit. Progressive memory impairment was notable in patients whose seizures were intractable, which suggested frequent seizures contributed this memory loss 15. Contralateral spikes on interictal EEG can appear along with the duration of epilepsy.…”