Outpatient EEG monitoring in the presurgical evaluation of patients with refractory temporal lobe epilepsy

Abstract

Most epilepsy centers obtain ictal EEG recordings to localize the epileptogenic zone during presurgical evaluations. Inpatient monitoring is standard practice but is expensive and can be inconvenient. The authors sought to determine whether outpatient monitoring can be safe and effective as the sole method of recording seizures in the presurgical evaluation of patients with refractory temporal lobe epilepsy. They reviewed the data of seven temporal lobectomy patients whose presurgical monitoring was performed entirely outside the hospital. Mean baseline seizure frequency was at least 9.1 seizures per week. An average of 7.4 seizures was recorded over 9.4 days of monitoring. Only one patient had any antiepileptic drug taper; none suffered any complications. After temporal lobectomy on the side of demonstrated ictal onset, postoperative follow-up averaged 5.5 years. At the most recent follow-up, all patients were either seizure free or had only rare disabling or nocturnal seizures (four patients had outcomes in Engel's class I and three patients in Engel's class II). A comparison group who underwent standard inpatient monitoring was similar in average seizure frequency, monitoring duration, number of seizures recorded, and postoperative outcome, although all but one had antiepileptic drugs tapered during monitoring. The authors conclude that there is a subset of patients for whom solely outpatient presurgical EEG monitoring can be used to help plan successful temporal lobectomy.