AREAS OF INTERICTAL SPIKING ARE ASSOCIATED WITH METABOLIC DYSFUNCTION
Abstract number :
3.194
Submission category :
Year :
2002
Submission ID :
841
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Jerry J. Shih, Michael P. Weisend, Roland R. Lee, John A. Sanders. Departments of Neurology and Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM; Department of Radiology, Albuquerque VA Medical Center, Albuquerque, NM
RATIONALE: Purpose: The objective of our study was to noninvasively determine if metabolic dysfunction is present in focal areas of interictal electrophysiologic abnormality and whether metabolic dysfunction correlates with frequency of spiking.
METHODS: We performed magnetoencephalography (MEG) and proton magnetic resonance spectroscopy (1H-MRS) on twenty subjects with nonlesional temporal lobe epilepsy. MEG was used to localize the source area of interictal spikes. 1H-MRS measured integrated peak areas for N-acetyl compounds (NAA) and choline-containing compounds (Cho) in both hippocampi, the MEG spike zone and the region contralateral to the MEG spike zone in all subjects. 1H-MRS was also performed in 7 controls.
RESULTS: Fifteen of 20 subjects had a lower NAA/Cho ratio in the MEG spike zone compared to the contralateral homologous region. NAA/Cho was significantly decreased in the MEG spike zone (p[lt]0.01). NAA/Cho ratios were not significantly different between the hippocampus ipsilateral and contralateral to the spike activity. NAA/Cho ratios did not correlate with spike frequency.
CONCLUSIONS: Metabolic dysfunction is present in focal areas of interictal spiking in nonlesional temporal lobe epilepsy. These findings confirm functional abnormalities can be detected in vivo in structurally normal cortex exhibiting abnormal excitability.
At the end of this activity, participants should be able to discuss possible metabolic changes associated with areas of interictal spiking.
[Supported by: NIH NCRR M01 RR00997-25S3]; (Disclosure: Honoraria - 4-D Neuroimaging)