Infant sleep at 10 months of age as a window to cognitive development.

This study examined the association between sleep-wake patterns and achievements on the Bayley Scales of Infant Development, in a low-risk sample of 10-month-olds. The sleep of 50 infants was recorded at home by means of a small activity monitor (actigraph). More motor activity in sleep and more fragmented sleep pattern were moderately associated with lower mental developmental index (MDI) scores. The psychomotor developmental index (PDI) was not associated with the sleep characteristics. The finding that at the end of the first year, sleep quality accounted for a significant, albeit small, percentage of the cognitive achievement variance is in line with a model that links sleep-wake states and behavior regulation during arousal.