Actigraphic Monitoring of the Activity-Rest Behavior of Preterm and Full-Term Infants at 20 Months of Age

Differences in the activity-rest behavior of preterm and full-term infants provide an important contribution to the analysis of the ontogeny of circadian rhythms. In this study, we recorded the activity-rest behavior of 17 preterm and 8 full-term infants at the approximate age of 20 months over an average of 10 days by means of actigraphic monitoring (Actiwatch®, Cambridge Neurotechnology Ltd.). At the same time, the parents of the infants kept a daily diary. The activity-rest rhythm, the nighttime sleep duration, the daytime rest duration, as well as the sleep quality of the infants were analyzed. Preterm and full-term infants at the age of 20 months show a circadian rhythm with a period length between 23 h 32 min (23:32 h) and 24 h 23 min (24:23 h). It can be concluded that the preterm and full-term infants all reached a vital developmental step by showing the dominant circadian rhythm in the spectrum. The daytime rest duration of preterm infants is significantly shorter than that of full-term infants. The sleep quality of preterm infants is significantly lower than that of full-term infants, which means that the preterm infants have a larger percentage of less restful nighttime sleep. In other studies preterm infants show an over-proportional frequency of attention deficit hyperactivity disorder (ADHD). For this reason, future analyses should reveal whether or not actigraphic monitoring is a suitable means for an early identification of activity-rest behavior in children who may develop ADHD.