Nap polygraphic recordings after partial sleep deprivation in patients with suspected epileptic seizures

A review of the literature shows that nap recordings make a significant contribution to epilepsy studies, providing evidence of specific EEG findings in patients suspected of having epilepsy. In addition, sleep deprivation can cause paroxysmal EEG activity and clinical seizures. We studied retrospectively 686 patients, 51.8% males and 48.2% females, who had experienced at least one episode classified from the clinical point of view as epileptic in origin. They were divided into six age groups. Patients underwent a two-hour (1 P.M.-3 P.M.) nap-video-polygraphic recording (EEG 13 channels using the standard 10-20 system, EOG, ECG, EMG and respiration), following a partial sleep deprivation (1 to 3 h) the night before. A second recording was made in 40 patients. In 35.3% of patients, a complete sleep cycle was obtained; in 64.6% sufficient light and deep NREM sleep was obtained, but not REM stage; in 9.3%, we only observed drowsiness and stage 1 of sleep, and this group was excluded from the analysis. Interictal and/or ictal epileptic discharges were observed during the first nap recording in 245 patients (40.4% of the sample). In addition, in 40 patients (11%) with normal or inconclusive first nap EEG, a second recording was able to demonstrate epileptic abnormalities in 35% of cases. Because of its good cost/benefit ratio and availability in most western laboratories, we consider the 'nap plus partial sleep deprivation' method as advantageous over other activation procedures.