Cognitive correlates of 1H MRSI-detected hippocampal abnormalities in temporal lobe epilepsy.
OBJECTIVE
To examine associations between 1H magnetic resonance spectroscopic imaging (1H MRSI)-detected hippocampal creatine to N-acetylaspartate (Cr/NAA) ratios and neuropsychological measures sensitive to mesial temporal lobe function.


BACKGROUND
The measurement of 1H MRSI-detected hippocampal metabolites has proved effective in determining extent and lateralization of neuronal damage. However, relationships between 1H MRSI-detected hippocampal metabolic abnormalities and specific areas of cognitive functioning have received limited attention compared to other studies using MRI volumetry or cerebral blood flow techniques.


METHODS
We analyzed right and left hippocampal Cr/NAA ratios in 46 adult mesial temporal lobe epilepsy patients (32 left, 14 right) by 1H MRSI at high magnetic field (4.1 T). We examined the relationship between the right and left Cr/NAA hippocampal ratios to measures of verbal and visual memory, intelligence, attention, visuoperception, and confrontation naming.


RESULTS
Measures of episodic verbal memory (n = 33) and visual confrontation naming (n = 46) were selectively associated with left hippocampal metabolic function (p<0.004), whereas neuronal function of the right hippocampal region was strongly associated with performance on a measure of facial recognition (n = 46; p<0.02).


CONCLUSIONS
This study shows that specific areas of cognitive function are related to hippocampal neuronal metabolic abnormalities as detected by spectroscopic imaging. The current study indicates that 1H MRSI offers a complimentary technique to structural imaging studies in the study of mesial temporal lobe epilepsy and may enhance understanding of the role of hippocampal function in complex cognitive systems.
Martin
R C
RC
UAB Epilepsy Center, Department of Neurology, University of Alabama at Birmingham, 35294-0021, USA.
Sawrie
S
S
Hugg
J
J
Gilliam
F
F
Faught
E
E
Kuzniecky
R
R
D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001931:Brain Mapping; D003072:Cognition Disorders / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D003401:Creatine / Q000378:metabolism; D004292:Dominance, Cerebral / Q000502:physiology; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006624:Hippocampus / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011612:Psychosurgery; D013702:Temporal Lobe / Q000503:physiopathology / Q000601:surgery
D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine