“…NICU sounds or light intensity can decrease infants' nonrapid eye movement sleep, which may have detrimental effects on their neurodevelopmental outcomes (Varvara, Effrossine, Despoina, Konstantinos, & Matziou, 2016). These impacts of NICU caregiving patterns and environmental stimuli on preterm infants' sleep have been studied either by observing sleep patterns or by electroencephalography, with few studies using actigraphy over 24 hr for 3 continuous days (Mirmiran & Ariagno, 2000;Yang, Yang, & Chang, 2014). Moreover, preterm infants' sleep patterns have been associated with characteristics such as postmenstrual age (PMA;Hoppenbrouwers et al, 2005;Mirmiran & Ariagno, 2000), body weight (Ingersoll & Thoman, 1999), gender (Hintz, Kendrick, Vohr, Kenneth, & Higgins, 2006), chronological age (Tyson, Parikh, Langer, Green, & Higgins, 2008), circadian rhythm, and illness severity (Buske-Kirschbaum, Krieger, & Wilkes, 2007;Goffaux, Lafrenaye, & Morin, 2008).…”