Localizing value of rapid eye movement sleep in temporal lobe epilepsy.

Sleep state is a physiological modulator of epilepsy. Non rapid-eye-movement (NREM) sleep generally increases interictal epileptiform discharges (IEDs) and expands their field of distribution. In contrast, rapid eye movement (REM) sleep tends to suppress IEDs and may limit their spread outside of the region of primary seizure origin. The ability of REM sleep to restrict IEDs may have localizing value in temporal lobe epilepsy patients undergoing evaluations for epilepsy surgery. We present the case of a woman with medically-refractory seizures secondary to a mesial temporal glioma. Although scalp and intracranial electroencephalographic (EEG) seizure recordings supported bilateral epileptic foci, the IEDs recorded during REM sleep were restricted to the region of the glioma, and the patient had a successful surgical outcome. Our findings support the usefulness of combining sleep recordings with EEG monitoring in the evaluation of candidates for epilepsy surgery.