Research Report Decrease of NAA with aging outside the seizure focus in mesial temporal lobe epilepsy—A proton-MRS study at 3 Tesla Franz Riederer a , Michal Bittšanský b,c , Eva Lehner-Baumgartner a , Christoph Baumgartner a , Vladimír Mlynárik c , Stephan Gruber c , Ewald Moser b,c,d , Marihan Kaya e , Wolfgang Serles a, ⁎ a Universitätsklinik für Neurologie, Abteilung für Klinische Epilepsieforschung, Medical University of Vienna, Währinger Gürtel 18-20, A 1090 Vienna, Austria b Universitätsklinik für Radiodiagnostik, Medical University of Vienna, Austria c Exzellenzzentrum Hochfeld MR, Medical University of Vienna, Austria d Zentrum für Biomedizinische Technik und Physik, Medical University of Vienna, Austria e Universitätsklinik für Neuropsychiatrie des Kindes-und Jugendalters, Medical University of Vienna, Austria ARTICLE INFO ABSTRACT Article history: Accepted 30 June 2007 Available online 14 July 2007 There is evidence that chronic pharmacoresistant temporal lobe epilepsy (TLE) is a progressive disorder accompanied by mental deterioration. We investigated effects of aging on cerebral N-acetyl-aspartate (NAA) concentrations in the temporal lobe of 12 patients with pharmacoresistant mesial TLE (mTLE) and 22 healthy controls by means of proton-magnetic resonance spectroscopy ( 1 H-MRS) at 3 T. Furthermore, we calculated correlations between NAA concentrations and measures of verbal and figural memory in patients. In mTLE patients but not in healthy controls the concentration of NAA in the lateral temporal lobe was negatively correlated with age. In patients with mTLE NAA in left lateral temporal voxels correlated with verbal memory. NAA in medial temporal voxels did not correlate with age or neuropsychological measures. Significant decrease of NAA with age in the lateral temporal lobe of patients with mTLE provides evidence for progressive neuronal dysfunction with aging. NAA is a marker of neuronal integrity since it correlates with verbal memory. © 2007 Elsevier B.V. All rights reserved. Keywords: Temporal lobe epilepsy N-acetyl-aspartate Disease progression Memory Seizure focus 1. Introduction Temporal lobe epilepsy is the most frequent form of partial epilepsy in adults. In most instances the seizure focus is located in the medial temporal lobe which shows hippocampal sclerosis, characterized by atrophy and/or elevated T2 signal of the hippocampus in the MRI scan and neuronal loss in the histologic examination. This is called mesial temporal lobe epilepsy (mTLE) (Engel, 1996). A part of patients with mTLE are pharmacoresistant and do not respond adequately to anti- epileptic treatment, i.e., they have repeated seizures after two consecutive treatments with one antiepileptic drug (mono- therapy) and one treatment with two or more antiepileptic drugs (polytherapy) (Bourgeouis, 1992). There is increasing evidence that chronic pharmacoresistant temporal lobe epi- lepsy (TLE) is a progressive disorder accompanied by cognitive BRAIN RESEARCH 1179 (2007) 131 – 139 ⁎ Corresponding author. Fax: +43 1 40400 3141. E-mail address: wolfgang.serles@meduniwien.ac.at (W. Serles). Abbreviations: 1 H-MRS, proton-magnetic resonance spectroscopy; mTLE, mesial temporal lobe epilepsy; NAA, N-acetyl-aspartate 0006-8993/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.brainres.2007.06.063 available at www.sciencedirect.com www.elsevier.com/locate/brainres