Correlation between memory, proton magnetic resonance spectroscopy, and interictal epileptiform discharges in temporal lobe epilepsy related to mesial temporal sclerosis

ObjectiveThe aim of the study described here was to examine the relationship between memory function, proton magnetic resonance spectroscopy (1H-MRS) abnormalities, and interictal epileptiform discharge (IED) lateralization in patients with temporal lobe epilepsy (TLE) related to unilateral mesial temporal sclerosis.MethodsWe assessed performance on tests of memory function and intelligence quotient (IQ) in 29 right-handed outpatients and 24 controls. IEDs were assessed on 30-minute-awake and 30-minute-sleep EEG samples. Patients had 1H-MRS at 1.5 T.ResultsThere was a negative correlation between IQ (P = 0.031) and Rey Auditory Verbal Learning Test results (P = 0.022) and epilepsy duration; between1H-MRS findings and epilepsy duration (P = 0.027); and between N-acetylaspartate (NAA) levels and IEDs (P = 0.006) in contralateral mesial temporal structures in the left MTS group. 1H-MRS findings, IEDs, and verbal function were correlated.ConclusionsThese findings suggest that IEDs and NAA/(Cho + Cr) ratios reflecting neural metabolism are closely related to verbal memory function in mesial temporal sclerosis. Higher interictal activity on the EEG was associated with a decline in total NAA in contralateral mesial temporal structures.