[The optimal examination duration for the detection of epileptiform discharge in outpatient...

Objective: To determine the optimal examination duration by evaluating the detection rate of epileptiform discharges (EDs) with different examination duration of video-electroencephalography (EEG) in outpatients. Methods: Patients with EDs who underwent 4-hour EEG examination from Xuanwu Hospital, Capital Medical University from October 2020 to November 2021 were retrospectively enrolled, and the detection rates of EDs were calculated with examination duration of 0-0.5 h, 0-1 h, 0-2 h, 0-3 h, and 0-4 h (group A, B, C, D and E), respectively. For each patient, EDs in each hour (group H1, group H2, group H3, group H4) were counted, and the standardized amount of EDs was calculated. For each patient, EDs in wakefulness, drowsiness, non-rapid eye movement-Ⅰ (NREM-Ⅰ), NREM-Ⅱ and NREM-Ⅲ were counted, and the standardized amount of EDs in each state was calculated. Meanwhile, the sleep duration per hour of each patient was also counted (group H1', group H2', group H3', group H4'). The Wilcoxon paired test was used for intergroup comparison to determine the optimal examination duration. Results: A total of 80 patients were enrolled, and aged [M(Q₁, Q₃)]31 (21, 39) years (range: 5-68 years). There were 38 males and 42 females. The detection rate of EDs was 42.5% (34/80) in group A, 81.3% (65/80) in group B, and 100.0% (80/80) in group C, group D and group E, respectively. The standardized amount of EDs of H1, H2, H3 and H4 was 24.8% (7.8%, 44.2%), 41.5% (25.9%, 63.3%), 15.1% (1.3%, 27.8%) and 1.3% (0, 14.5%), respectively. The standardized amount of EDs of H2 was significantly higher than that of H1, H3 and H4 (all P<0.05). The standardized amount of EDs in wakefulness, drowsiness, NREM-Ⅰ, NREM-Ⅱ and NREM-Ⅲ were 9.6% (0, 28.2%), 3.6% (0, 16.9%), 3.3% (0, 11.8%), 47.3% (21.9%, 72.5%) and 0 (0, 11.5%), respectively. The standardized amount of EDs in NREM-Ⅱ was significantly higher than that in wakefulness, drowsiness, NREM-Ⅰ and NREM-Ⅲ (all P<0.05). The sleep duration in the group of the H1', H2', H3' and H4' was 13.6 (2.5, 23.6), 35.8 (16.5, 54.2), 14.5(0, 34.7) and 0 (0, 14.6) minutes, respectively. The sleep duration in the group of the H2' group was significantly longer than that in the group of H1', H3' and H4' (all P<0.05). Conclusion: The study recommends 2 hours video-EEG in outpatients, which not only ensures the detection rate of EDs, but also facilitates patient cooperation and optimizes the allocation of medical resources.