Variations in habitual sleep and relational memory in 6-month-olds

Adequate sleep duration and good sleep quality are considered essential for development, especially during periods of major neurodevelopmental change. Still, relations between parent-reported habitual sleep and emerging cognitive abilities within the first year of life are not well studied. Here, we examined relations between habitual sleep measures and an aspect of cognitive functioning, relational memory, which emerges as early as 6 months of age, as compared to other abilities (ie, recognition memory and attentional orienting), both of which are considered to emerge earlier in development. Participants were a subset of 267 healthy typically developing 6-month-olds taking part in the Growing Up in Singapore towards Healthy Outcomes cohort study. Sleep duration, sleep latency, and number and duration of night awakenings were derived from the Brief Infant Sleep Questionnaire (BISQ). Short sleep was defined as