Sleep affects infant development and temperament
Sleep during infancy is important to the maturation of the brain and CNS.
There is nothing quite as peaceful as watching babies sleep, which is nice because they certainly to do a fair amount of it during the first few months of life. The importance of this sleep is just beginning to be understood.
A literature review looked at the effects of sleep in infancy to see whether there were correlations between sleep and development (Sleep. 2009;32:1449-1458). Of course, as the authors point out, it is difficult to generalize when studies are compared because of variations in testing methods and developmental differences. However, some of the studies showed similar information.
What we can tell, through polysomnography and developmental studies, as well as through animal studies, is that there is a great deal going on during the first year of life. Sleep during infancy is important to the maturation of the brain and central nervous system, as well as future cognition, temperament, and psychomotor development. The most dramatic changes in the central nervous system happen in the first two years of life.
An infant's sleep is comprised of increased REM sleep initially and is then divided between non-REM and REM sleep equally until approximately age 6 months. At that time, REM sleep occurs about 30% of the night. Most babies have developed a somewhat normal sleep cycle by age 3-6 months.
Several studies suggest that normal sleep development means higher mental development scores. In all studies, lower socioeconomic class was correlated with lower mental scores.
Infants who slept less both during the day and night have been found to have “difficult” temperaments. Infants who were awake more of the night were more irritable at age 3 months. It has also been shown that children who had difficulty sleeping during the night were less approachable. Conversely, children who had increased sleep were shown to have “easy” temperaments and were more approachable.
The National Sleep Foundation provides several recommendations that you can share with parents with new babies. Parents should observe their infant's sleep habits and learn to identify when the child is sleepy. Putting the child to bed when he or she is drowsy but still awake will help infants learn to self-soothe. Always place the baby on his or her back. Encourage nighttime sleeping to promote good circadian rhythm. Of course, soothe the baby when appropriate and make sure all other needs are met before bedtime (e.g., feeding and diaper changes).
Enjoy those wonderful moments when your little one is sleeping happily. The fun is only beginning. Just wait until they are about four or five and don't want to go to bed. You'll be wishing they were babies again.