Brain maturation in the first 3 months of life, measured by electroencephalogram: A comparison between preterm and term-born infants.

OBJECTIVE: Preterm infants are at risk for altered brain maturation resulting in neurodevelopmental impairments. Topographical analysis of high-density electroencephalogram during sleep matches underlying brain maturation. Using such an EEG mapping approach could identify preterm infants at risk early in life. METHODS: 20 preterm (gestational age < 32 weeks) and 20 term-born infants (gestational age > 37 weeks) were recorded by 18-channel daytime sleep-EEG at term age (GA 40 weeks for preterm and 2-3 days after birth for term infants) and 3 months (corrected age for preterm infants). RESULTS: Preterm infant's power spectrum at term age is immature, leveling off with term infants at 3 months of age. Topographical distribution of maximal power density however, reveals qualitative differences between the groups until 3 months of age. Preterm infants exhibit more temporal than central activation at term age and more occipital than central activation at 3 months of age. Moreover, being less mature at term age predicts being less mature at 3 months of age. CONCLUSION: Topographical analysis of sleep EEG reveals changes in brain maturation between term and preterm infants early in life. SIGNIFICANCE: In future, automated analysis tools using topographical power distribution could help identify preterm infants at risk early in life.

The Zurich 3-step concept for the management of behavioral sleep disorders in children: a before-and-after study.

OBJECTIVES: Several strategies have been found to be effective for the treatment of childhood behavioral sleep disorders. One which has yet to be evaluated is the Zurich 3-step concept, which combines basic notions of the two-process model of sleep regulation (introducing a regular rhythm and adjusting bedtime to sleep need) with behavioral strategies. This uncontrolled before-and-after study describes our concept and its step-wise approach, assesses changes in sleep-wake variables and behavior problems, and also examines associations between changes in sleep-wake variables and behavior problems. METHODS: A total of 79 children with sleep problems (age range 6-47 months, 42% females) were included. Sleep problems were assessed by the Infant Sleep Questionnaire, sleep-wake variables by diary and actigraphy, and behavior problems of children ≥ 18 months by the Child Behavior Checklist. RESULTS: A significant decrease in nocturnal wake duration (Cohen's d = -0.34) and a significant increase in the duration of the longest continuous nocturnal sleep period (Cohen's d = 0.19) were found from before to after intervention (on average 2.7 months, SD 1.5). The variability for sleep onset and end time decreased, and actigraphically measured circadian rest-activity cycle measures improved. Parent-reported internalizing and total behavior problems also decreased (Cohen's d = 0.66). CONCLUSIONS: The findings of both objective and subjective assessment techniques suggest that the Zurich 3-step concept is effective. Thus, the intervention concept may be useful in clinical practice with sleep-disordered children.

Very preterm infants show earlier emergence of 24-hour sleep-wake rhythms compared to term infants.

BACKGROUND: Previous studies show contradictory results about the emergence of 24-h rhythms and the influence of external time cues on sleep-wake behavior in preterm compared to term infants. AIMS: To examine whether very preterm infants (<32 weeks of gestational age) differ in their emergence of the 24-h sleep-wake rhythm at 5, 11 and 25 weeks corrected age compared to term infants and whether cycled light conditions during neonatal intermediate care affects postnatal 24-h sleep-wake rhythms in preterm infants. STUDY DESIGN: Prospective cohort study with nested interventional trial. SUBJECTS: 34 preterm and 14 control term infants were studied. During neonatal hospitalization, preterm infants were randomly assigned to cycled light [7 am-7 pm lights on, 7 pm-7 am lights off, n=17] or dim light condition [lights off whenever the child is asleep, n=17]. OUTCOME MEASURES: Sleep and activity behavior recorded by parental diary and actigraphy at 5, 11 and 25 weeks corrected age. RESULTS: Sleep at nighttime and the longest consolidated sleep period between 12 pm-6 am was longer (mixed model analysis, factor group: p=0.02, resp. p=0.01) and activity at nighttime was lower (p=0.005) at all ages in preterm compared to term infants. Cycled light exposed preterm infants showed the longest nighttime sleep duration. Dim light exposed preterm infants were the least active. CONCLUSIONS: Preterm infants show an earlier emergence of the 24-h sleep-wake rhythm compared to term infants. Thus, the length of exposure to external time cues such as light may be important for the maturation of infant sleep-wake rhythms. Trial registry number: This trial has been registered at www.clinicaltrials.gov (identifier NCT01513226).

Cycled light exposure reduces fussing and crying in very preterm infants.

OBJECTIVE: To examine whether cycled lighting (CL) conditions during neonatal care in very preterm infants (<32 weeks' gestational age [GA]) decrease crying and fussing behavior, improve the consolidation of sleep, and influence activity behavior at 5 and 11 weeks' postterm corrected age (CA) compared with preterm infants cared for in dim lighting (DL) conditions. METHODS: Thirty-seven preterm infants were randomly assigned to CL (7 am-7 pm lights on, 7 pm-7 am lights off [n = 17; mean GA: 30.6 ± 0.95 weeks; 9 girls]) or DL (lights off whenever the child is asleep [n = 20; GA: 29.5 ± 2.1 weeks; 8 girls]) conditions. Sleeping, crying, and activity behavior was recorded by using parental diaries and actigraphy at 5 and 11 weeks' CA. RESULTS: A significant reduction of fussing (59.4 minutes/24 hours [± 25.8 minutes]) and crying (31.2 minutes/24 hours [± 14.4 minutes]) behavior and a trend to higher motor activity during daytime was found in CL-exposed infants at 5 and 11 weeks' CA compared with infants cared for in DL conditions. No significant difference between groups was observed for sleep behavior at 5 and 11 weeks' CA. Infants in CL conditions showed a trend to improved daily weight gain (average: 3.6 g/d) during neonatal care compared with DL conditions. CONCLUSIONS: CL conditions in neonatal care have beneficial effects on infant's fussing and crying behavior and growth in the first weeks of life. This study supports the introduction of CL care in clinical neonatal practice.

Agreement rates between actigraphy, diary, and questionnaire for children's sleep patterns.

OBJECTIVES: To describe sleep-wake patterns in kindergarten children by measures derived from questionnaire, diary, and actigraphy and to report rates of agreement between methods according to Bland and Altman. DESIGN: Cross-sectional study, data from 7 nights of actigraph recordings and sleep diary and from a questionnaire. SETTING: Children studied in their homes. PARTICIPANTS: Fifty children, aged 4 to 7 years. MAIN OUTCOME MEASURES: Sleep start, sleep end, assumed sleep, actual sleep time, and nocturnal wake time derived from different methods. RESULTS: Differences between actigraphy and diary were +/- 28 minutes for sleep start, +/- 24 minutes for sleep end, and +/- 32 minutes for assumed sleep, indicating satisfactory agreement between methods, whereas for actual sleep time and nocturnal wake time, agreement rates were not sufficient (+/- 106 minutes and +/- 55 minutes, respectively). Agreement rates between actigraphy and questionnaire as well as between diary and questionnaire were insufficient for all variables. Sex and age of children and socioeconomic status did not influence the differences between methods for all variables. CONCLUSIONS: Actigraphy and diary may be interchangeably used for the assessment of sleep start, sleep end, and assumed sleep but not for nocturnal wake times. The diary is a cost-effective and valid source of information about children's sleep-schedule times, while actigraphy may provide additional information about nocturnal wake times or may be used if parents are unable to report in detail. It is insufficient to collect information by a questionnaire or an interview asking about children's normal sleep patterns.