Creating an optimal observational sleep stage classification system for very and extremely preterm infants

Sleep plays a major role in neuronal survival and guiding the fetal brain's development. Preterm infants in the neonatal intensive care unit are exposed to numerous external stimuli that can severely disrupt their sleep/wake patterns. Currently, almost no behavioral classification scales are validated for preterm infants. This study aims to develop a new, easy-to-use, validated visual sleep stage classification system for preterm infants with a gestational age between 25 and 37 weeks.The Behavioral Sleep stage classification for Preterm Infants (BeSSPI) consists of four sleep-wake stages; active sleep (AS), quiet sleep (QS), intermediate sleep (IS) and wake (W), which are classified using seven items. Items include eye movements, body movements, facial movements, vocalizations, heart rate, respiratory pattern and activity level.69 preterm infants were observed (24 + 6-36 + 0 weeks GA at birth; 25 + 2-36 + 6 weeks PMA at observation; 57.3% male). Across all 69 infants, the BeSSPI was based on 10,922 min of observed behavior, with 4264 min AS (38.83%), 2873 min QS (26.16%), 2887 min IS (26.29%), and 957 min W (8.72%). For the final BeSSPI, an interrater agreement of κ = 0.80 was reached. Additionally, construct, content, face validity, and expert validity were carefully assessed and deemed satisfactory.We developed a method to evaluate sleep-wake stages that is simple for all neonatal healthcare providers to learn and use. The BeSSPI is of high reliability and validity. Furthermore, it can be used in all preterm age-groups. Therefore, this novel instrument may improve rigor and reproducibility for future preterm sleep research.