Aaron DeMasi, Sarah E. Berger, Melissa N. Horger, & Angelina M. Allia
Presented at the International Congress of Infant Studies 2020
Despite an overall decrease in night wakings over the first year, infants experience a spike in night wakings when gaining new motor skills. For example, infants who can crawl awaken more often at night than infants who cannot yet crawl and the onsets of pulling-to-stand and walking disrupt sleep-wake regulation (Scher, 2005; Atun-Euny & Scher, 2016; Berger & Moore, 2019). To address the underlying mechanisms of this relationship, we describe how infants’ nighttime wake episodes (WEPs) serve as opportunities to practice new motor skills. Do the types of movements produced during nighttime WEPs change as infants expand their locomotor repertoires?
Parents of three infants kept diaries of infant sleep schedules and motor milestone onsets. Video data were collected using Nanit, a commercial home baby monitor, which livestreams video of the infant’s crib to parents’ smart devices. 98 hours of video of infants in their cribs from the nights before, of, and after infants first began crawling (n = 2; 1 male) and walking (n = 1 male) were coded using a video-coding software for identifying frequencies/durations of behavior. Motor behaviors during nighttime WEPs were coded from video (see Table 1 for definitions). To meet criteria, WEPs had to occur 10 minutes after sleep onset, last five or more minutes, and have codable movement at least once every 3 minutes. A WEP ended with the last movement before five minutes of continuous stillness.
On average, infants exhibited twice as many movements per WEP minute on the night of locomotor onset (M = 2.65, SD = 1.74) than the nights before (M = 1.81, SD = 0.88) and after (M = 1.54, SD = 0.33). There were twice as many types of movements during WEPs on the night of locomotor onset (M = 11.00, SD = 2.65) than the nights before (M = 5.67, SD = 2.08) and after (M = 5.67, SD = 1.15). Types of movements during WEPs were more variable during the night of locomotor onset than on the nights before or after. Type of movement was related to skill onset: the only time an infant crawled during a WEP was on his night of crawling onset and the only time an infant stood independently during a WEP was on his night of walking onset. The only night infants rotated on hands-and-knees during a WEP was the night they learned to crawl. Infants shifted sleep position the most on the night after skill onset. Mean proportions of movement types out of total movements are displayed in Figure 1. Data collection is ongoing.
Infants moved more and expressed greater diversity in movements during WEPs when they reached new locomotor milestones. We also demonstrated that Nanit, a commercially available video baby monitor, is a useful research tool and can provide a detailed glimpse into infants’ nighttime crib environments. Infants may experience more disrupted sleep around motor milestone onsets because they are utilizing wake episodes as opportunities to practice their motor skills, prolonging wake episodes and further fragmenting sleep.
About the Researchers
The researchers included Aaron DeMasi, Sarah E. Berger, Melissa N. Horger, & Angelina M. Allia
Dr. Sarah Berger is a Professor of Psychology at the College of Staten Island and the Graduate Center of the City University of New York. She received her PhD from New York University. Dr. Berger was an American Association of University Women Postdoctoral Research Fellow and a Fulbright Research Scholar. Dr. Berger studies the interaction between cognitive and motor development in infancy, particularly response inhibition and its implications for the allocation of attention in very young children. A line of National Science Foundation (NSF)-funded work, in collaboration with Dr. Anat Scher, has been the first to study the impact of sleep on motor problem solving in infancy.