Correlation of scalp EEG and H-1-MRS metabolic abnormalities in temporal lobe epilepsy

Purpose: To correlate the interictal spike field and region of seizure onse t with the distribution of H-1-MRS abnormalities in temporal lobe epilepsy (TLE) and improve our understanding of the clinical significance of H-1-MRS abnormalities. Methods: Scalp electroencephalogram (EEG) monitoring and proton magnetic re sonance spectroscopy (H-1-MRS) results were correlated in 31 consecutive pa tients with TLE. Results: Lateralized H-1-MRS-based hippocampal abnormalities were recorded in 95% of the patients with unilateral interictal spikes, with a high degre e of concordance for the lateralization side (90%). In 64% of the patients with normal or bilateral interictal EEG spikes, H-1-MRS provided lateralizi ng information. Bilateral H-1-MRS abnormalities, with or without lateraliza tion, were 3 times more frequent than bitemporal EEG spikes. Anterior predo minance of the H-1-MRS abnormalities was more frequent in patients with ant erior temporal EEO spiking (50%), than in patients without this EEG distrib ution (18%). Similar association was noted between distribution of H-1-MRS abnormalities and region of EEG seizure onset. Conclusions: Our results show a moderate level of concordance between the d istribution of H-1-MRS and EEG abnormalities. H-1-MRS identifies abnormalit ies contralateral to the predominant seizure focus more often than does EEG and may provide lateralizing information in patients with nonlateralizing interictal EEG.