Investigation of Absolute Delta Power During N3 Sleep in Patients with REM-Dependent Obstructive Sleep Apnea: A Single-Center Case-Control Study

Authors : Elif Simin Issı, Selahattin Ayas
Pages : 35-41
Doi:10.20515/otd.1783673
View : 33 | Download : 119
Publication Date : 2025-12-15
Article Type : Research Paper
Abstract :This study aimed to evaluate macro- and micro-architectural parameters of the N3 sleep stage in patients with REM-dependent obstructive sleep apnea (OSA). This single-center retrospective study compared the macroarchitecture and delta band measures of Non-Rapid Eye Movement sleep stage 3 (N3) between healthy individuals (n=20), patients with Sleep-stage independent obstructive sleep apnea (OSA, n=20), and those with Rapid Eye Movement (REM)-dependent OSA (n=20). REM-dependent OSA was defined by an apnea–hypopnea index (AHI) ≥5/hour, a REM/NREM AHI ratio ≥2, and a REM duration of at least 30 minutes. Analyses were performed on the longest artifact-free 5-minute N3 segment in the first half of the night, using the F3–A2 derivation and a Welch-based spectral method. Absolute delta power (1–4 Hz, µV²) and % Slow-Wave Activity (SWA)-N3 (1–4/1–50 Hz) were calculated. The N3 duration and percentage showed significant differences between groups (p=0.004 and p=0.002, respectively), with longer and higher values in the control group. However, absolute delta power (p=0.396) and %SWA-N3 (p=0.122) showed no significant differences between groups. These findings indicate that N3 duration is significantly reduced in OSAS phenotypes, but N3 depth remains at the same level as in controls. To our knowledge, this study is among the few to directly assess N3 delta power in the REM-dependent OSA subgroup, thus contributing novel evidence to the field. Future research is needed in larger cohorts using multiple N3 segments and covariance-adjusted models (e.g., age, BMI, hypoxemia indices).
Keywords : Obstrüktif uyku apne sendromu, REM uykusu, N3 uykusu, Elektroensefalografi, Polisomnografi, Delta dalgası

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