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

Öz

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).

Anahtar Kelimeler

• Obstructive sleep apnea
• REM sleep
• N3 sleep
• Electroencephalography
• Polysomnography
• Delta wave

REM-bağımlı Obstürktif Uyku Apne Sendromlu Hastalarda N3 Uyku Evresinde Mutlak Delta Gücünün Araştırılması: Tek Merkez Vaka-Kontrol Çalışması

Öz

Bu çalışmada REM-bağımlı obstrüktif uyku apne sendromlu (OUAS) hastalarda N3 uyku evresinin makro ve mikromimarisine ait parametrelerin değerlendirilmesi amaçlanmıştır. Bu tek merkezli retrospektif çalışmada sağlıklı bireyler (n=20), uyku evresi ile ilişkili olmayan OUAS’lı hastalar (n=20) ve REM-bağımlı OUAS’lı (n=20) hastalar arasında N3 uykusunun makro mimarisi ile delta bandı ölçütleri karşılaştırıldı. REM-bağımlı OUAS, AHI≥5/saat, AHI REM/AHI NREM≥2 ve REM süresi≥30 dakika ölçütleriyle tanımlandı. Analizler gecenin ilk yarısındaki en uzun artefaktsız N3 segmentinde, F3–A2 kanalından Welch tabanlı spektral yöntemle yürütüldü; mutlak delta gücü (1–4 Hz, µV²) ve %SWA-N3 (1–4/1–50 Hz) hesaplandı. Gruplar arasında N3 süresi ve yüzdesi anlamlı farklılık gösterdi (N3 süre p=0.004; %N3 p=0.002); normal grupta N3 süresi ve yüzdesi daha uzun ve yüksekti. Buna karşın mutlak delta gücü (p=0.396) ve %SWA-N3 (p=0.122) açısından fark saptanmadı. Bu bulgular, OUAS fenotiplerinde N3 evresinin süresinin anlamlı düzeyde azaldığını, ancak N3 derinliğinin kontrol grubundakiyle aynı seviyede kaldığını göstermektedir. Çalışma, REM-bağımlı OUAS alt fenotipinde N3 delta gücünü doğrudan karşılaştıran az sayıdaki araştırmadan biri olması nedeniyle literatüre katkı sağlamaktadır. Gelecek çalışmalarda çoklu N3 segmentleri ve kovaryans ayarlı modellerle (örn. yaş, BMI, hipoksemi göstergeleri) daha geniş örneklemler önerilir.

Anahtar Kelimeler

• Obstrüktif uyku apne sendromu
• REM uykusu
• N3 uykusu
• Elektroensefalografi
• Polisomnografi
• Delta dalgası

Kaynakça

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