Asymmetric interictal glucose hypometabolism and cognitive performance in epileptic patients.
OBJECTIVE
To relate hemispheric metabolic asymmetries to cognitive performance in patients with unilateral mesial temporal lobe epilepsy.


METHODS
Asymmetrical cerebral glucose metabolisms on interictal fludeoxyglucose F 18 positron emission tomograms (FDG-PET) were correlated with cognitive measures. Analyses included partial correlations that controlled for the correlation between metabolic asymmetries of the lateral temporal lobe and other brain regions and the correlation of IQ scores with affected cognitive scores.


METHODS
A university epilepsy surgery center.


METHODS
Subjects included 13 patients who had intractable complex partial seizures originating from a mesial temporal lobe.


METHODS
Patients underwent FDG-PET scanning as part of their diagnostic work-up. Asymmetry indexes for cerebral metabolic rates were determined for whole hemisphere, lateral temporal lobe, mesial temporal lobe, frontal lobe, thalamus, and parietal lobe.


METHODS
The following cognitive domains were assessed: psychometric intelligence, mental control/attention, language, and verbal and nonverbal memory. Neuropsychological measures were obtained within 14 days of FDG-PET scanning.


RESULTS
Relative reductions in glucose metabolism of the left hemisphere and left lateral temporal lobe correlated with a lower verbal IQ score and a lower score on a verbal memory task, recall of logical prose. Relative reduction in metabolism of the left side of the thalamus also correlated with lower scores for recall of logical prose.


CONCLUSIONS
Relative hypometabolism of the left hemisphere correlates with lower cognitive performance. Hypometabolism of the left lateral temporal lobe and thalamus independently correlates with the verbal memory difficulties seen in this epileptic patient population.
Rausch
R
R
Department of Neurology, UCLA.
Henry
T R
TR
Ary
C M
CM
Engel
J
J
Mazziotta
J
J
D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D003071:Cognition; D003847:Deoxyglucose / Q000031:analogs & derivatives; D004833:Epilepsy, Temporal Lobe / Q000378:metabolism* / Q000523:psychology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D014055:Tomography, Emission-Computed
D019788:Fluorodeoxyglucose F18; D003847:Deoxyglucose; D005947:Glucose