Infant motor development predicts the dynamics of movement during sleep

The characteristics of infant sleep change over the first year. Generally, infants wake and move less at night as they grow older. However, acquisition of new motor skills leads to temporary increases in night waking and movement at night. Indeed, sleep-dependent movement at night is important for sensorimotor development. Nevertheless, little is known about how movement during sleep changes as infants accrue locomotor experience. The current study investigated whether infant sleep and movement during sleep were predicted by infants\u27 walking experience. Seventy-eight infants wore an actigraph to measure physical activity during sleep. Parents reported when their infants first walked across a room \u3e10 feet without stopping or falling. Infants in the midst of walking skill acquisition had worse sleep than an age-group estimate. Infants with more walk experience had more temporally sporadic movement during sleep and a steeper hourly increase in physical activity over the course of the night. Ongoing motor skill consolidation changes the characteristics of movement during sleep and may alter sleep state-dependent memory consolidation. We propose a model whereby changes in gross motor activity during night sleep reflect movement-dependent consolidation

Motor Milestone Acquisition and Sleep-Related Learning and Development in Infancy

The aim of this dissertation is to summarize and extend work in the field of infant sleep and motor development. Chapter 1 summarizes what is currently known about typical infant sleep development and the way that sleep impacts learning throughout infancy. Chapter 2 describes two experiments showing the importance of napping and night sleep in the consolidation of gross motor learning. Given that sleep is beneficial for learning throughout human infancy, the remainder of the dissertation investigates how learning (in this case, motor development) impacts sleep. Chapter 3 establishes the possible role of sleep-dependent movement in sleep disruption resulting from gross motor experience. Chapters 4 and 5 examine the different attributes of movement during sleep and how they change with motor milestone acquisition. The results of the study in Chapter 4 suggest that each motor milestone impacts sleep and the spatial aspects of movement differently. Using the microgenetic method, Chapter 5 expands on the movement that infants are engaged in at night surrounding the acquisition of crawling and walking and finds that infants perform potentially skill-relevant movements at the onset of each skill. Finally in Chapter 6, I propose a new cyclical model of motor development and sleep and discuss limitations and future directions for work in the field of infant motor development and infant sleep