Electroencephalogram derived sleep microarchitecture in patients with interstitial lung disease and obstructive sleep apnea.

INTRODUCTION

Sleep disturbances are common in patients with interstitial lung diseases (ILD) and are often compounded by comorbid obstructive sleep apnea (OSA). Conventional polysomnographic indices may not fully capture disease-specific neurophysiological alterations.

METHODOLOGY: We aimed to characterize EEG-derived sleep microarchitecture in ILD with comorbid OSA (ILD-OSA) and compare it with ILD without OSA and apnea hypopnea index matched non-ILD OSA (n = 20 in each group). Quantitative EEG analysis was performed using standardized preprocessing and data extraction protocols. Spectral power, slow wave and spindle metrics, and a novel measure of micro-continuity (Neuroloop gain), reflecting the brain's propensity to generate and sustain sleep spindles and slow oscillations, were computed and compared across the groups.

RESULTS

Sleep macro and microarchitecture were similar between ILD with and without OSA. However, compared with non-ILD OSA, patients with ILD-OSA exhibited higher spindle amplitude and power, with preserved slow-wave characteristics. Notably, spindle neuroloop gain was significantly reduced in ILD-OSA.

CONCLUSIONS

Patients with ILD-OSA demonstrate differences in EEG-derived sleep microarchitecture compared with non-ILD OSA patients, particularly in spindle dynamics. These findings suggest that quantitative EEG may provide additional insights into sleep neurophysiology in ILD that warrant confirmation in larger prospective studies.