Objective. The main purpose of the present study was to calculate percentile curves for total sleep duration per 24 hours, for nighttime and for daytime sleep duration from early infancy to late adolescence to illustrate the developmental course and age-specific variability of these variables among subjects. Methods. A total of 493 subjects from the Zurich Longitudinal Studies were followed using structured sleep-related questionnaires at 1, 3, 6, 9, 12, 18, and 24 months after birth and then at annual intervals until 16 years of age. Gaussian percentiles for ages 3 months to 16 years were calculated for total sleep duration (time in bed) and nighttime and daytime sleep duration. The mean sleep duration for ages 1 to 16 years was estimated by generalized additive models based on the loess smoother; a cohort effect also had to be included. The standard deviation (SD) was estimated from the loess smoothed absolute residuals from the mean curve. For ages 3, 6, and 9 months, an alternative approach with a simple model linear in age was used. For age 1 month, empirical percentiles were calculated. Results. Total sleep duration decreased from an average of 14.2 hours (SD: 1.9 hours) at 6 months of age to an average of 8.1 hours (SD: 0.8 hours) at 16 years of age. The variance showed the same declining trend: the interquartile range at 6 months after birth was 2.5 hours, whereas at 16 years of age, it was only 1.0 hours. Total sleep duration decreased across the studied cohorts (1974–1993) because of increasingly later bedtime but unchanged wake time across decades. Consolidation of nocturnal sleep occurred during the first 12 months after birth with a decreasing trend of daytime sleep. This resulted in a small increase of nighttime sleep duration by 1 year of age (mean 11.0 ± 1.1 hours at 1 month to 11.7 ± 1.0 hours at 1 year of age). The most prominent decline in napping habits occurred between 1.5 years of age (96.4% of all children) and 4 years of age (35.4%). Conclusions. Percentile curves provide valuable information on developmental course and age-specific variability of sleep duration for the health care professional who deals with sleep problems in pediatric practice.

Sleep duration from infancy to adolescence: reference values and generational trends.

Pediatric obstructive sleep apnea (OSA) has become widely recognized only in the last few decades as a likely cause of significant morbidity among children. Many of the clinical characteristics of pediatric OSA, and the determinants of its epidemiology, differ from those of adult OSA. We systematically reviewed studies on the epidemiology of conditions considered part of a pediatric sleep-disordered breathing (SDB) continuum, ranging from primary snoring to OSA. We highlight a number of methodologic challenges, including widely variable methodologies for collection of questionnaire data about symptomatology, definitions of habitual snoring, criteria for advancing to further diagnostic testing, and objective diagnostic criteria for SDB or OSA. In the face of these limitations, estimated population prevalences are as follows: parent-reported “always” snoring, 1.5 to 6%; parent-reported apneic events during sleep, 0.2 to 4%; SDB by varying constellations of parent-reported symptoms on questionnaire, 4 to 11%; OSA diagnosed by varying criteria on diagnostic studies, 1 to 4%. Overall prevalence of parent-reported snoring by any definition in meta-analysis was 7.45% (95% confidence interval, 5.75–9.61). A reasonable preponderance of evidence now suggests that SDB is more common among boys than girls, and among children who are heavier than others, with emerging data to suggest a higher prevalence among African Americans. Less convincing data exist to prove differences in prevalence based on age. We conclude by outlining specific future research needs in the epidemiology of pediatric SDB.

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Epidemiology of pediatric obstructive sleep apnea

The authors used meta-analytical techniques to estimate the magnitude of gender differences in mean level and variability of 35 dimensions and 3 factors of temperament in children ages 3 months to 13 years. Effortful control showed a large difference favoring girls and the dimensions within that factor (e.g., inhibitory control: d = -.41, perceptual sensitivity: d = -0.38) showed moderate gender differences favoring girls, consistent with boys' greater incidence of externalizing disorders. Surgency showed a difference favoring boys, as did some of the dimensions within that factor (e.g., activity: d = 0.33, high-intensity pleasure: d = 0.30), consistent with boys' greater involvement in active rough-and-tumble play. Negative affectivity showed negligible gender differences.

Gender differences in temperament: a meta-analysis.

The aim of this study was to examine the associations between sleep and neurobehavioral functioning (NBF) in school-age children. These variables were assessed for 135 unreferred, healthy school children (69 boys and 66 girls), from second-, fourth-, and sixth-grade classes. Objective assessment methods were used on the participants in their regular home settings. Sleep was monitored using actigraphy for 5 consecutive nights; and NBF was assessed using a computerized neurobehavioral evaluation system, administered twice, at different times of the day. Significant correlations between sleep-quality measures and NBF measures were found, particularly in the younger age group. Children with fragmented sleep were characterized by lower performance on NBF measures, particularly those associated with more complex tasks such as a continuous performance test and a symbol-digit substitution test. These children also had higher rates of behavior problems as reported by their parents on the Child Behavior Checklist. These results highlight the association between sleep quality, NBF, and behavior regulation in child development; and raise important questions about the origins of these associations and their developmental and clinical significance.

/pdf/sleep-neurobehavioral-functioning-and-behavior-problems-in-57y3ccctz0.pdf

Sleep, neurobehavioral functioning, and behavior problems in school-age children

Objective. To develop and validate (using subjective and objective methods) a brief infant sleep questionnaire (BISQ) that would be appropriate for screening in pediatric settings. Design. Two studies were performed to assess the properties of the BISQ. Study I compared BISQ measures with sleep diary measures and objective actigraphic sleep measures for clinical ( N = 43) and control ( N = 57) groups of infants (5–29 months of age). The second study was based on an Internet survey of 1028 respondents who completed the BISQ posted on an infant sleep web site. Results. In study I, BISQ measures were found to be correlated significantly with sleep measures derived from actigraphy and sleep diaries. BISQ measures (number of night wakings and nocturnal sleep duration) were the best predictors for distinguishing between clinical and control samples. High test-retest correlations ( r > .82) were demonstrated for BISQ measures for a subsample of 26 infants. Study II provided a developmental perspective on BISQ measures. The study demonstrated that BISQ measures derived from a large Internet survey provided developmental and sleep ecology-related findings that corresponded to the existing literature findings on sleep patterns in early childhood. Conclusions. The findings provide psychometric, clinical, and ecologic support for the use of the BISQ as a brief infant sleep screening tool for clinical and research purposes. Potential clinical cutoff scores are provided.

A Brief Screening Questionnaire for Infant Sleep Problems: Validation and Findings for an Internet Sample

A cohort of 172 children was followed from 6 months to 7 years of age to determine how nap patterns change with age and whether there was individual stability of nap patterns. Results showed that there were no differences in nap patterns based on gender, ordinal position, whether naps spontaneously disappeared or were stopped by the parents, and the number of naps at 6 months of age. Total daytime sleep remained a stable individual characteristic between 6 and 18 months of age. Age was associated with hours napping (r = -0.73, p < 0.001) and number of naps (r = -0.52, p < 0.001). A pattern of two naps per day was well established by 9-12 months of age and one afternoon nap by 15-24 months. The modal duration of naps from 2 to 6 years was 2 hours. During the 3rd and 4th year, napping occurred in the majority of children, but at decreasing rates. A minority of children were napping at 5 and 6 years and naps usually disappeared by age 7.

Naps in children: 6 months-7 years.

Treatment of infantile colic with dicyclominehydrochloride

Night waking in 4- to 8-month-old infants

Infant temperament ratings and parental reports of sleep patterns and sleep durations were obtained on 105 normal infants. Boys with more difficult temperaments and active sleep patterns had brief attention spans compared to the other children (p = 0.005). Among all infants, active sleep pattern was associated with maleness and increased activity ratings when awake (both p less than 0.05). Infants with easy temperaments slept longer than those with difficult temperaments (14.9 +/- 0.2 versus 12.8 +/- 0.5 hours, p less than 0.001). Gender, maternal prenatal smoking, method of feeding, and infant sleep position did not affect attention span ratings or sleep durations.

Sleep patterns, attention span, and infant temperament.

Parental reports of sleep patterns, ratings on the Behavioral Style Questionnaire, and Conners' Abbreviated Parents' Questionnaire were obtained for 60 three-year-old children. Children who were more adaptable, mild, and positive in mood, or children with an easy temperament, had longer total sleep durations and lower Conners' ratings than children with opposite traits. Adaptability was the temperament characteristic most highly correlated with total sleep duration and the only characteristic which correlated with the number of night wakings. In addition, children with low activity ratings had long total sleep durations, low Conners' ratings, and were described as having a quiet sleep pattern. Long sleep durations and low Conners' ratings appear to be features of children with an easy temperament or low motor activity when awake and asleep.

Marc Weissbluth

Papers

Naps in children: 6 months-7 years.

Treatment of infantile colic with dicyclominehydrochloride

Night waking in 4- to 8-month-old infants

Sleep patterns, attention span, and infant temperament.

Sleep duration, temperament, and Conners' ratings of three-year-old children.