Study On Sleep/wake Patterns And Their Relationships With Temperaments And Recognition Of Premature Infants

Objective To describe the developmental characteristics of sleep/wake patterns longitudinally in their own home environments aged from birth to 4 months corrected gestational age in 32-36 weeks relatively low-risk premature infants and their relationships with temperaments and recognition.Methods 27 relatively low-risk premature infants from the NICU of Qingdao Children's Hospital were enrolled from 2011.11-2012.7 in this study.Data was collected with actigraphy over 3 days continuously about 60 hours at day 2,day 10,from 1 months to 4 months corrected gestational age monthly.The temperaments dimension and mental development index were collected with infant temperaments questionnaire and Bayley scales of infant development when infants were 6 months old..The measures were analyzed by SAS and SPSS 17.0 with the ANOVE of repeated measures,Bonferroni test and partial correlation analysis were also used.Stastical analysis of test level is a=0.05.Results Among the 4 months corrected gestational ages,the 24 hour sleep duration and daytime sleep duration decreased with age,while the nocturnal sleep duration increased slowly.Compared with Day 2 after birth,the relevant values at 4 months old varied by 4.44h,4.85h and1.27h respectively,the differences was statistically significant.The reduction of the 24h sleep duration was due to the shrink of daytime sleep duration,which was especially tremendous in the first 2 months.For premature infants,daytime sleep duration was dominated in the first 2 months,and later evolved to nocturnal sleep duration.The numbers of naps changed slowly within the 4 months corrected gestational ages,at 3-4 times each day,There was no statistically different between adjacent ages.The numbers of nighttime awakening after birth were 1.9 times,At 10 days,1-4 months corrected gestational ages each month,the nighttime awakening numbers were 3.4,3.4,4.1,3.6 and 2.9 times respectively.Apart from day 2 and day 10,there was no statistically different between adjacent ages.Still,the ability of continuous sleep strengthened gradually,with the longest sleep duration 4.7h at 2 days old,the revelant value was 2.75h at day 10.The average longest sleep duration remained 3.55 h from 1 month to 3 month,which did not change statistically,then it growed to 4.3h at 4 months old.Latter bedtime and earlier morning wake time appeared as the infants growing.There was no sex statistical differences in the index of mentioned above.Compared with term infants,there was less 24 sleep duration and nocturnal sleep duration after 1 month old for preterm infant,while more daytime sleep duration.Still premature infants had a higher proportion of daytime sleep duration in the early ages.As for sleep ability,premature infant was still poorer.Correlation coefficient(R)was 0.599 between emotion and sleep latency at night.There were also positive correlations between persistence and daytime sleep duration and numbers of naps.After controlling the parents'education level,family economic conditions and gestational age,this study did not find correlation between sleep/wake parameters and mental development index(MDI).Conclusions The characteristic of sleep/wake patterns in premature infants was different with ages,and the sleep/wake mode was same as term infants.Compared with term infants,premature infant had more daytime sleep duration and poorer sleep ability.There were correlations between sleep/wake patterns and emotion and persistence,but we did not find correlations between sleep/wake patterns and recognition.