Self-reported seizure frequency and time to first event in the seizure monitoring unit.

PURPOSE: To compare seizure frequency reported in the clinic with time to first diagnostic event during video-EEG monitoring. The effect of the artificial environment of the monitoring unit on self-reported seizure frequency was explored. METHODS: The 155 consecutive patients were seen in the Washington University Epilepsy Center and subsequently underwent video-EEG monitoring during 2001. Of these, 112 had a diagnostic event during monitoring; 31 left without having a definite event; and 12 could not provide an estimate of seizure frequency in the clinic. The time to first event was compared with self-reported seizure frequency. The patients were then divided into three equal groups (tertiles) based on mean seizure frequency, and time to first seizure was compared between groups. Then the numbers of patients staying >7 days without ever having an event were compared between the low and high seizure-frequency groups. Finally, Kaplan-Meier survival curves were calculated. RESULTS: No correlation was found between self-reported seizure rate and time to diagnostic event (r= 0.18; p = 0.06). Time to first event was 2.8 days in the low seizure-frequency group (mean, 2.2/month), 2.1 days in the medium (mean, 8.8/month), and 2.1 days in the high (mean, 24.1/month) groups, which were not significantly different (p = 0.19). Of patients in the low-frequency group, 79% had an event within 7 days. CONCLUSIONS: In the artificial environment of the monitoring unit, self-reported outpatient seizure frequency is not an accurate predictor of duration of video-EEG monitoring required to make a definitive classification of clinical events and should not contribute to the decision as to whether to refer a patient for monitoring.

Correlation of severity of FDG-PET hypometabolism and interictal regional delta slowing in temporal lobe epilepsy.

PURPOSE: We investigated the association of severity of hypometabolism detected by positron emission tomography (PET) with [(18)F]fluorodeoxyglucose (FDG) and persistence of interictal EEG focal slowing in patients with refractory temporal lobe epilepsy. METHODS: Eighty temporal lobes of 40 consecutive patients with intractable temporal lobe epilepsy (mean age, 43.5 years) were studied. All patients underwent video-EEG monitoring, magnetic resonance imaging (MRI), and FDG-PET. Patients with either normal MRI or with unilateral mesial temporal sclerosis, but no other structural abnormality, were included. Interictal EEG delta slowing was graded as none, infrequent (one episode or less/hour), intermediate (more than one episode/hour), or continuous. PET hypometabolism was graded as none, mild, moderate, or severe. RESULTS: The severity of temporal lobe hypometabolism with PET was significantly correlated with the amount of delta activity in the interictal EEG, independent of MRI findings (Spearman r = 0.46; p < 0.0005). CONCLUSIONS: This observation suggests related underlying pathophysiologic mechanisms for metabolic and electrical dysfunction in temporal lobe epilepsy.