Withdrawal of antiepileptic drugs during presurgical video-EEG monitoring: an observational study for evaluation of current practice at a referral center for epilepsy.

OBJECTIVES

Withdrawal of antiepileptic drugs (AEDs) before and during video-EEG-monitoring is commonly implemented to reduce time needed to register a sufficient number of seizures during presurgical evaluation. There are, however, few guidelines regarding withdrawal rate and observation time.

MATERIAL AND METHODS

We performed an observational study including sixty patients admitted to the national Norwegian epilepsy centre and registered tapering of AEDs and their effect on seizure rate and possible complications.

RESULTS

The mean daily seizure rate before admission to the EMU was 0.4 (range 0.02-4) increasing to 1.1 (range 0-8) at the EMU. 29 patients (48%) followed a slow tapering rate whereas 31 (52%) had an intermediate tapering rate. There was no significant difference between the patients with a daily seizure rate during LTM of more or <0.7 seizures per day, an increase of seizure frequency from habitual to during LTM of more or <3.3 or 6.9 with regard to rate of tapering (slow vs intermediate) etiology or AED monotherapy vs polytherapy. Twenty-six patients (43%) had a sufficient number of seizures registered within 3 days to conclude regarding the presurgical evaluation. Two patients received escape treatment while 25 patients did have 24 h-seizure-clusters. There was no serious event.

CONCLUSIONS

Less than 50% of the patients got a sufficient number of seizures for a conclusive result within 3 days. An increase in the registration period could increase the number of successful registrations.