Relationships among hippocampal volumetry, proton magnetic resonance spectroscopy, and verbal memory in temporal lobe epilepsy.
OBJECTIVE
To examine the relationship between hippocampal volumes, 1H magnetic resonance spectroscopy (MRS)-identified hippocampal metabolic function, and verbal memory in patients with unilateral mesial temporal lobe epilepsy (MTLE).


METHODS
Hippocampal volumes, 1H MRS-derived hippocampal creatine to N-acetylaspartate (Cr/NAA), and verbal memory assessment were obtained preoperatively in 22 patients (six right, 16 left) with EEG-defined unilateral MTLE.


RESULTS
Left hippocampal volume correlated significantly with left hippocampal Cr/NAA (r=-0.549, p < 0.01), whereas right volume correlated significantly with right Cr/NAA (r=-0.478, p < 0.05). Verbal memory correlated significantly with left hippocampal Cr/NAA (r=-0.594, p < 0.01), but not with left hippocampal volume or right hippocampal measures.


CONCLUSIONS
Hippocampal volumes and 1H MRS-derived metabolite ratios are statistically related, but share only a small percentage of variance, suggesting separate but related pathophysiologic processes. Left hippocampal Cr/NAA appears to be more sensitive to verbal memory function than volumes.
Sawrie
S M
SM
Epilepsy Center, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA. ssawrie@uab.edu
Martin
R C
RC
Knowlton
R
R
Faught
E
E
Gilliam
F
F
Kuzniecky
R
R
D000328:Adult; D017668:Age of Onset; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D004569:Electroencephalography / Q000706:statistics & numerical data; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000378:metabolism / Q000601:surgery; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006624:Hippocampus / Q000033:anatomy & histology* / Q000378:metabolism / Q000601:surgery; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008568:Memory / Q000502:physiology; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D014706:Verbal Learning / Q000502:physiology
D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine