Cerebral metabolic topography in unilateral temporal lobe epilepsy

Abstract

Relative to normal values, both elevations and depressions of metabolism exist interictally in TLE. Such abnormalities, and accompanying changes in interregional correlations, may have wide spatial distribution. These findings are atypical among PET studies but are consistent with other physiologic, anatomic, and neuropsychological investigations of TLE.

Covariance PET patterns in early Alzheimer's disease and subjects with cognitive impairment but no dementia: utility in group discrimination and correlations with functional performance

“…SSM is a form of principal component analysis that employs the construct of "networks or patterns of localized physiological activity" to capture the multidimensional nature of functional activity at individual brain locations Moeller et al, 1987). This method has been used previously in resting imaging studies of normal aging and a variety of diseases (Eidelberg et al, 1995a(Eidelberg et al, ,b, 1996(Eidelberg et al, , 1998Feigin et al, 2001a, b ;Feigin et al, 2001a, b ;Hutchinson et al, 2000;Moeller et al, 1996;Rubin et al, 1995;Sackeim et al, 1990Sackeim et al, , 1993Stern et al, 2000;Su et al, 2001). …”

“…Multivariate techniques have been used to explore resting imaging data in many neurological and psychiatric conditions (Eidelberg et al, 1995a(Eidelberg et al, ,b, 1996(Eidelberg et al, , 1998Feigin et al, 2001a, b ;Feigin et al, 2001a, b ;Fukuda et al, 2001;Hutchinson et al, 2000;Moeller et al, 1996;Nakamura et al, 2001;Rubin et al, 1995;Sackeim et al, 1990Sackeim et al, , 1993Su et al, 2001). RCBF covariance among brain regions that participate in the pattern may be thought of as coordinated biochemical or synaptic activity, suggesting some sort of connectivity between these areas.…”

“…In contrast, these methods have been used in resting PETor SPECTstudies of normal aging , stroke (Leibovitch et al, 1999), epilepsy (Rubin et al, 1995), Parkinson's disease (Eidelberg et al, 1995a;Feigin et al, 2001a,b;Moeller et al, 1996), subthalamotomy, pallidotomy or pallidal stimulation in Parkinson's disease Fukuda et al, 2001;Su et al, 2001), Huntington's disease (Feigin et al, 2001a,b), blepharospasm (Hutchinson et al, 2000) dystonia (Eidelberg et al, 1995b(Eidelberg et al, , 1998 and depression (Sackeim et al, 1990(Sackeim et al, , 1993.…”

Unitemporal vs Bitemporal Hypometabolism in Mesial Temporal Lobe Epilepsy

“…Asymmetry indices of the temporal lobe against cerebellar or whole cerebral metabolism were used recently. 11,12 However, the propagation of seizure discharges may lead to cerebellar damage, and cerebellar blood flow and glucose metabolism often decrease in patients with partial seizures. 4,11 The method that used whole cerebral metabolism as a reference also may produce a false result due to frequent extratemporal hypometabolism in mesial TLE.…”

Reversible Kernohan notch

“…28 Rate of brain glucose metabolism is largely dependent on pyramidal neuron activation and subsequent glutamate release, and recent studies indicate that glucose utilization is directly related to glia uptake of glutamate 32 The wide variability of hippocampal neuron/glia ratios commonly described in temporal lobe epilepsy 17 may explain previous observations of extremes of interictal hyper-and hypometabolism in different regions in mesial temporal sclerosis. 33 This variability may also explain the lack of correlation of hippocampal glucose metabolism with symptoms of depression. Alternatively, NAA synthesis is dependent on mitochondrial enzymes, including L-aspartate N-acetyltransferase, and coenzyme A, which may be more sensitive to clinically significant limbic dysfunction in temporal lobe epilepsy than is glucosedependent basal energy maintenance.…”