EEG and ECG Microstructure Markers During Apnea Transition Phases in Central and Obstructive Sleep Apnea

Year 2026, Volume: 14 Issue: 1, 517 - 533, 26.03.2026

Onur Koçak , Ziya Telatar

https://doi.org/10.29109/gujsc.1837129

https://izlik.org/JA65NK95MJ

Abstract

This study aimed to characterize EEG- and ECG-derived microstructural markers during apnea transitions in central sleep apnea (CSA) and obstructive sleep apnea (OSA), and to examine how these transient dynamics vary across sleep stages and apnea severity. Polysomnography data from 32 male patients (16 CSA, 16 OSA) were retrospectively analyzed. EEG sub-band energies (delta, theta, alpha, beta), pulse transit time (PTT), Hjorth parameters, and frequency-domain HRV (LF/HF) were computed for pre-apnea, intra-apnea, and post-apnea epochs. Patients were additionally stratified by AHI. Group comparisons were performed using parametric and non-parametric tests with Bonferroni adjustment. OSA and CSA demonstrated distinct electrophysiological patterns. CSA showed increasing EEG sub-band power and decreasing PTT from pre- to intra-apnea, indicating rapid autonomic adjustment with minimal sleep architecture disruption. OSA exhibited reduced EEG power, lengthened PTT, and greater beta activation during apnea, consistent with arousal-like intrusions. Stage-specific analysis revealed that REM sleep displayed the most pronounced transitions, marked by delta–theta enhancement and alpha–beta suppression. In N2 and N3, delta activity showed characteristic divergence across apnea intervals, highlighting unique microstructural adaptations within each stage. High-resolution EEG and ECG features provide complementary insights into the physiological mechanisms distinguishing OSA from CSA. Event-level EEG microstructures captured transient cortical dynamics not visible in conventional scoring, suggesting their potential value as early biomarkers of respiratory instability. These findings may support improved diagnostic accuracy and individualized management strategies in sleep apnea.

Keywords

Sleep apnea , EEG , ECG , microstructure , HRV , pulse transit time , apnea transitions , spectral analysis

Ethical Statement

The study was conducted with the approval of Prof. Dr. Hikmet Fırat, Clinical Chief of the Sleep Disorders Center at the Ministry of Health, Türkiye, Dışkapı Yıldırım Beyazıt Training and Research Hospital, using retrospective data obtained from patients who had previously been hospitalized for diagnostic purposes. No additional data were collected specifically for this study. Written informed consent for the collection of polysomnography recordings during the patients’ clinical stay at the sleep center had been obtained. The study was carried out in accordance with the principles of the Declaration of Helsinki.

Supporting Institution

The authors declared that they have received no financial support.

Thanks

The authors would like to thank Prof. Dr. Sadık Ardıç, Prof. Dr. Hikmet Fırat and Prof. Dr. Osmar Eroğul for their invaluable guidance, feedback, and supervisory support throughout the study.

Merkezi ve Obstrüktif Uyku Apnesinde Apne Geçiş Evrelerinde EEG ve EKG Mikroyapı Belirteçleri

https://izlik.org/JA65NK95MJ

Abstract

Bu çalışma, santral uyku apnesi (CSA) ve obstrüktif uyku apnesi (OSA) sırasında meydana gelen apne geçişlerinde EEG ve EKG’den türetilen mikroyapı belirteçleri tanımlamayı ve bu geçici dinamiklerin uyku evreleri ile apne şiddetine göre nasıl değiştiğini incelemeyi amaçlamıştır. Toplam 32 erkek hastaya ait tam gece polisomnografi kayıtları (16 CSA, 16 OSA) geriye dönük olarak analiz edilmiştir. Pre-apne, intra-apne ve post-apne epokları için EEG alt bant enerjileri (delta, teta, alfa, beta), nabız geçiş zamanı (PTT), Hjorth parametreleri ve frekans alanı HRV (LF/HF) değerleri hesaplanmıştır. Hastalar ayrıca AHI gruplarına göre sınıflandırılmıştır. Grup karşılaştırmaları parametrik ve parametrik olmayan testlerle, Bonferroni düzeltmesi kullanılarak yapılmıştır. OSA ve CSA arasında belirgin elektrofizyolojik farklılıklar gözlenmiştir. CSA’da pre-apneden intra-apneye geçişte EEG alt bant güçleri artarken, PTT azalmış; bu durum minimal uyku mimarisi bozulmasıyla birlikte hızlı otonom yanıtları göstermiştir. OSA’da ise EEG gücü azalmış, PTT uzamış ve apne sırasında beta aktivitesi artmış olup, bu durum uyanıklık benzeri geçişlerle uyumludur. Evreye özgü analizler, özellikle REM uykusunda delta–teta artışı ve alfa–beta baskılanmasıyla belirgin geçişler olduğunu ortaya koymuştur. N2 ve N3 evrelerinde delta aktivitesinin apne dönemlerine göre karakteristik değişimleri, evreye özgü mikroyapı adaptasyonları göstermiştir. Yüksek çözünürlüklü EEG ve EKG özellikleri, CSA ve OSA’yı ayırt eden fizyolojik mekanizmalar hakkında tamamlayıcı bilgiler sunmaktadır. Olay düzeyindeki EEG mikroyapıları geleneksel skorlamada görünmeyen geçici kortikal dinamikleri yakalayarak solunumsal instabilitenin erken belirteçleri olabilir. Bu bulgular, uyku apnesinin tanısal doğruluğunu artırmaya ve bireyselleştirilmiş tedavi stratejilerini desteklemeye katkı sağlayabilir.

Keywords

Uyku apnesi , EEG , EKG , mikroyapı KHD (kalp hızı değişkenliği) , nabız geçiş zamanı , apne geçişleri , spektral analiz

Ethical Statement

Çalışma T.C. Sağlık Bakanlığı Dış Kapı Yıldırım Beyazıt Eğitim ve Araştırma Hastanesi Uyku Bozuklukları Merkezi Klinik Şefi Prof. Dr. Hikmet Fırat'ın olurları ile daha önceden merkezde teşhis amaçlı yatan hastaların retrospektif verileri kullanılarak gerçekleştirilmiştir. Kliniğe yatan hastalardan bu çalışmaya özgü ayrıca bir veri alınmamıştır. Hastaların uyku merkezindeki yatışları sırasında toplanan polisomnografi verileri için yazılı aydınlatılmış onam alınmıştır. Çalışma, Helsinki Deklarasyonu İlkeleri’ne uygun olarak yürütülmüştür.

Supporting Institution

“Yazarlar, çalışmaya yönelik herhangi bir finansal destek almadıklarını beyan etmektedir.”

Thanks

Yazarlar, çalışma boyunca sağladıkları değerli rehberlik, geri bildirim ve danışmanlık destekleri için Prof. Dr. Sadık Ardıç, Prof. Dr. Hikmet Fırat ve Prof. Dr. Osmar Eroğul’a teşekkür ederler.

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