0072 Infant Sleep at 9 Months Predicts Language Skills at 12 Months

Abstract Introduction Habitual sleep patterns in infants and children have been linked to developmental outcomes such as language. In children, language development is positively associated with sleep consolidation, efficiency, and duration. Studies examining this relationship in infants are less consistent; one found frequent daytime naps among infants and toddlers predicted vocabulary growth 3-6 months later, while another found more consolidated sleep at 18 months predicted language skills at 5 years. Conversely, frequent night awakenings are consistently associated with poorer language development. We sought to determine key sleep features that predict language learning in infancy. Methods 9-month-old infants (n=18) wore an actigraph (GENEActiv) on their ankle for up to 16 days (M = 11.5 days). Actigraphy was used to objectively measure infants’ sleep duration, timing (sleep onset latency, midpoint, and consolidation ratio [total nap time/night sleep time]) and quality (sleep efficiency, wake after sleep onset [WASO]). Infants’ expressive and receptive language skills at 12- and 15 months were measured using the Bayley Scales of Infant and Toddler Development. Results Among the sleep timing variables, only their consolidation ratio was significantly related to receptive language (R^2=.223, p=.037; all other p’s>.05). Nighttime sleep efficiency at 9 months was positively related to both receptive (R^2=.255, p=.027) and expressive (R^2=.278, p=.02) language scores at 12 months. Nighttime WASO was negatively related with receptive (R^2=.332, p=.019) and expressive (R^2=.356, p=.014) language scores at 12 months. Nine month sleep features were not associated with language scores at 15 months. Conclusion Measures of both sleep timing and quality at 9 months were related to language scores at 12 months. Increased sleep efficiency and decreased WASO predicted higher expressive and receptive language scores. Our finding adds to prior research that fewer night awakenings may benefit language development. Additionally, a greater ratio of daytime to nighttime sleep was associated with better receptive language outcomes, indicating that longer and/or more frequent daytime naps may be beneficial for receptive language development at this age point. Support (if any) Funding: NIH R01 HL169995