24-Hour Video EEG in the Evaluation of the Seizure-Free Patient Before Antiseizure Medication Withdrawal.

Abstract

Purpose: In patients with epilepsy who achieve seizure freedom, physicians may consider discontinuing antiseizure medications, often using EEG beforehand to guide the decision. This study evaluates the gain in detection of epileptiform discharges (EDs) in 24-hour video EEG (VEEG) monitoring in seizure-free patients.

Methods: The authors identified patients with epilepsy who were seizure free on antiseizure medications and had undergone 24-hour VEEG after an unrevealing routine EEG. The authors evaluated the yield and latency of observed EDs in the VEEG study. The authors compared the rate of ED detection during the first 60 minutes versus later in the recording.

Results: Of the 27 patients, aged 19 to 51 years, 10 (37%) exhibited EDs on 24-hour VEEG. The latency to the first EDs ranged from 52 to 748 minutes, with a median of 164 minutes. Nine of these 10 patients (90%) had their EDs appear only after the first 60 minutes of recording. In other words, prolonging the EEG beyond 1 hour yielded an additional 33.3% of patients with EDs that a 1-hour recording would have missed. Younger age and presence of EDs on a past EEG were predictive of the presence of EDs on VEEG ( P = 0.040 and P = 0.039 respectively).

Conclusions: The results suggest that 24-hour VEEG is more sensitive in detecting EDs than routine EEG in seizure-free patients and thus may be superior in individualized risk assessments for seizure recurrence on potential antiseizure medication discontinuation.