Kavitha Venkatnarayan, Fathima Ayoob, Arun Sasidharan, Rahul Venugopal, Chitra Veluthat, Priya Ramachandran, Uma Devaraj, Uma Maheswari Krishnaswamy
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.
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.