Impact of clinical covariates on the performance of an automatic sleep stage classification in preterm infants

Frequent sleep disruption in preterm infants in neonatal intensive care units (NICU) is suspected to be associated with adverse neurodevelopmental outcomes. A continuous, noninvasive sleep monitoring solution could optimise care by aligning interventions with natural sleep–wake cycles. The algorithm for automatic sleep stage classification by Demme et al. [5] offers a promising approach, with an accuracy of 92.2 ± 0.01% compared to sleep stages measured in the sleep laboratory. This study aims to evaluate the applicability of the sleep classification algorithm with regards to two main questions: (1) Does the algorithm’s performance vary with factors like pre-existing medical conditions or other patient characteristics in preterm infants? (2) How well does the algorithm capture sleep stage transitions compared to manual annotations? This study is a secondary analysis of data previously used by Demme et al. [5] to train models for automatic sleep stage classification in preterm infants. The models, which were trained on manual annotations of polysomnography (PSG) data, were applied to a diverse cohort of preterm infants. The performance was analysed in relation to medical conditions, sex, gestational age (GA), apnoea–hypopnea index (AHI), bodyweight at measurement, and Fleiss’ kappa (a measure of interrater variability). Sleep stage transition frequencies were compared between algorithmic and manual scoring. No significant performance differences could be observed with respect to any covariates, except for a reduction in performance among patients with low Fleiss’ kappa values, suggesting classification difficulties in cases in which manual raters have come to diverging assessments. Transition analysis revealed significant differences, likely due to the algorithm’s more sensitive ability to detect short sleep stage transitions. The algorithm shows strong performance and generalisability. Despite some discrepancies in sleep stage transition detection, it appears suitable for noninvasive, continuous sleep monitoring in the NICU, supporting sleep-aware clinical care.