Gerontological Effects on Arousal Frequency, Autonomic Balance, and Slow-Wave Sleep During Pressure Adjustments of CPAP in OSA Patients

Objective: Continuous positive airway pressure (CPAP) therapy is recognized as first-line treatment for obstructive sleep apnea (OSA), but tolerance to pressure adjustments may differ with age. In this study, we examined age-related differences in physiological and neurophysiological responses following CPAP pressure adjustment. Methods: In this retrospective study, we analyzed baseline polysomnography (PSG) and CPAP titration data from 40 individuals, including 20 younger (<65 years) and 20 older adults (≥65 years) matched at the group level. Time-specific analyses were conducted using 10-min windows following pressure adjustments. Group comparisons across predefined pressure categories of CPAP (4–5, 6–7, and ≥ 8 cmH₂O) and age groups were performed using one-way analysis of variance (ANOVA) or Kruskal–Wallis tests, as appropriate, with post-hoc analyses. Single and multiple linear regression analyses were conducted to assess associations between CPAP pressure categories and physiological responses, using the 4–5 cmH₂O group as the reference and adjusting for prior pressure change history and sleep-stage distribution. Results: Both age groups demonstrated improvements in sleep architecture and sleep disorder indices during CPAP titration. Among older individuals, analyses of 10-min periods following pressure adjustments showed a higher arousal frequency, increased elevated standard deviation (SD) of normal-to-normal (NN) intervals (SDNN) and low-frequency (LF)/high-frequency (HF) ratios, and reduced slow-wave peak-to-peak amplitudes and slopes compared to younger counterparts. Regression analyses further indicated associations between pressure categories, HRV features, and slow-wave characteristics in the elderly group. Conclusion: These findings highlight potential age-related differences in short-term responses to pressure adjustments for CPAP. Future prospective studies are needed to validate and enhance the generalizability and robustness of these findings.