Seppä-Moilanen M, et al. - In this 2013-2015 study, researchers enlisted 21 preterm infants on neonatal wards in the Helsinki and Uusimaa Hospital District, Finland, at a median corrected gestational age of 35.7 weeks and performed polysomnography at baseline, during supplemental oxygen and during caffeine treatment to examine the characteristics and impacts of sleep stage, supplemental oxygen and caffeine on periodic breathing (PB) and apnea of prematurity (AOP) in preterm infants. They found that PB occurred predominantly during non-rapid eye movement sleep, caused intermittent hypoxia, and was suppressed by supplemental oxygen and caffeine. It was noted that long apnea episodes representing AOP were only modestly decreased.