Temporal lobe epilepsy with sensory aura: interictal glucose hypometabolism

Patients with mesial temporal lobe epilepsy (mTLE) exhibit marked depressio ns of the regional cerebral glucose metabolism (rCMRGlu) in the mesiotempor al region. We hypothesised that patients with temporal lobe epilepsy (TLE) who have a bilateral somatosensory or acoustic (= temporolateral/SII-) aura can be differentiated from mTLE by rCMRGlu depressions primarily involving temporo-perisylvian locations. We therefore used this ictal semiology as a clinical criterion to define a subgroup of such patients and measured the rCMRGlu in 16 patients with TLE as evident from interictal and ictal EEG-vi deo monitoring. Clinically, they presented with medically refractory comple x partial seizures and were subjected to presurgical evaluation. The patter n of the interictal rCMRGlu in the TLE patients was different from that obs erved in patients with mTLE and showed significant depressions ipsilateral to the epileptic focus in mesial temporal and lateral temporal regions but spared the thalamus. The neocortical metabolic depressions were spatially m ore extended in right than in left TLE patients. Magnetic resonance images (MRI) were either normal (n = 5) or revealed unilateral or bilateral hippoc ampal atrophy/sclerosis (n = 7), or temporal or extratemporal focal cortica l dysplasia (n = 4). The selected TLE patients presented here comprise a he terogeneous group showing most pronounced metabolic depressions in the late ral temporal cortex. Thus, our data suggest that non-invasive metabolic ima ging can assist in identifying the neocortical symptomatogenic zone in puta tive temporoperisylvian lobe epilepsy. (C) 2000 Elsevier Science B.V. All r ights reserved.