Related Experiment Video
Updated: Aug 5, 2026
Association Between Sleep Quality and Cognitive Symptoms in Patients with Major Depressive Disorder
Published on: April 26, 2024
Subjective sleep quality reflects sleep continuity rather than respiratory severity or sleep stage composition
Damla Azakli Yazici1, Eslem Gül1, Ecem Bilensoy1
1Basaksehir Cam and Sakura City Hospital, Department of Pulmonology, Istanbul, Turkey.
Background:
Positive airway pressure (PAP) therapy normalizes respiratory events in obstructive sleep apnea (OSA), yet many patients report poor sleep quality despite adequate physiological control. This suggests that conventional respiratory indices may fail to capture key determinants of subjective sleep experience. We hypothesized that sleep continuity, rather than respiratory severity or sleep stage composition, is more closely associated with perceived sleep quality.
Methods:
In this cross-sectional study, adults undergoing in-laboratory polysomnography (PSG), including diagnostic and PAP titration nights, completed the Groningen Sleep Quality Scale (GSQS) after awakening. Polysomnographic variables reflecting respiratory metrics, sleep architecture, and continuity were extracted. Logistic regression identified predictors of poor subjective sleep quality (GSQS ≥6). Discrimination was assessed using receiver operating characteristic analysis, and a continuity-based Objective Sleep Quality Index (OSQI) was derived.
Results:
Among 37 participants, 68% reported poor subjective sleep quality. Respiratory indices, including apnea-hypopnea index (AHI), oxygenation measures, and REM- or non-REM-specific event rates, did not differ between good and poor sleepers. In contrast, poor subjective sleep quality was associated with longer wake after sleep onset (WASO), reduced sleep efficiency, and increased N1 sleep. WASO was the strongest predictor. A parsimonious model including WASO, the first uninterrupted sleep period (FUSP), and sex showed the best discrimination (AUC 0.85). The OSQI demonstrated good sensitivity and specificity.
Conclusions:
Subjective sleep quality after laboratory studies appears to be more closely associated with sleep continuity than with respiratory severity or sleep stage composition. A continuity-based index integrating WASO, FUSP, and sex showed promising discriminatory performance but requires validation in larger independent cohorts.
Related Concept Videos
01:22Stages of Sleep
Before sleep begins, in wakefulness, the brain exhibits primarily beta waves, which are high in frequency and low in amplitude, indicating alertness...
01:24Sleep-Wake Cycles
NREM Sleep
NREM sleep comprises four progressive stages that seamlessly merge:
01:24Substance Use Disorders Affecting Sleep
Understanding the concepts of physical dependence,...
01:29Assessment of Ventilation II: Respiratory Depth and Rhythm
Respiratory depth measures the volume of air inhaled or exhaled during a breath. It can vary from shallow to deep and typically remains consistent when a person is at rest or asleep. Occasionally, individuals will automatically inhale deeply, known as sighing, which inflates the lungs with more air than normal breathing.
To assess respiratory depth, observe the degree of chest excursion or movement:
01:13Insufficient Sleep and Sleep Deprivation
Sleep deprivation is a more severe form of sleep loss...
01:26Respiratory Volumes and Capacities I