Lauren E. Philbrook

Sleep and Development: Familial and Socio-cultural Considerations

A biopsychosocial framework has guided much of our research program pertaining to children’s and adolescents’ sleep and development. In this chapter, we first present findings from studies examining sleep parameters (e.g., duration, quality) as predictors and outcomes, as well as vulnerability and protective factors across multiple domains of development (e.g., cognitive functioning, mental and physical health). The importance of transactional models and longitudinal designs is emphasized in our work. Secondly, the multi-faceted ways we have assessed children’s sleep in the context of family processes is illustrated, with a focus on family conflict. Thirdly, the importance of the broader socio-cultural milieu on children’s sleep is highlighted, with a focus on race/ethnicity (African- and European-American) and economic adversity. Finally, open scientific questions and recommendations for moving the field forward, especially those of particular relevance to family studies and child development researchers, are presented.

Associations between neighborhood context, physical activity, and sleep in adolescents ☆

OBJECTIVE This study examined how neighborhood access to recreation facilities and physical activity are linked to multiple indices of adolescent sleep. Physical activity was also assessed as a mediator of the association between access to recreation facilities and sleep. DESIGN The study used a cross-sectional design and path modeling analysis techniques. SETTING Participants were recruited from small towns and semi-rural communities in Alabama. PARTICIPANTS Participants were 231 adolescents (55% female) with an average age of 16.75 years (SD = .81). Sixty-seven percent of the youth were European American and 33% were African American. The sample was socioeconomically diverse with more than a third of participants living at or below the poverty line and less than half from middle class families. MEASUREMENTS Adolescent neighborhood access to recreation facilities and physical activity were assessed via self-report. Sleep minutes, efficiency, and schedule were measured using actigraphy. RESULTS Access to recreation facilities was associated with more sleep minutes and later morning wake time, as well as a trend towards increased sleep efficiency. Access to recreation facilities was also linked to more physical activity, and physical activity was related to more sleep minutes, later wake time, and less wake time variability. Physical activity was a mediating and intervening link between access to recreation facilities and these sleep parameters. CONCLUSIONS Findings implicate physical activity as one mechanism linking neighborhood context to adolescent sleep. The results suggest that establishing more neighborhood opportunities for physical activity may have cascading effects on multiple aspects of adolescent physical health.

Associations between bedtime and nighttime parenting and infant cortisol in the first year.

We examined how maternal care within the bedtime and nighttime contexts influences infant cortisol levels and patterning. Eighty-two mothers (Mage  = 29.4 years) and infants participated in a longitudinal study when infants were 3, 6, and 9 months old. At each time point, bedtime and nighttime parenting were recorded and infant cortisol at bedtime and the following morning was analyzed. Multilevel model analyses showed that infants had lower cortisol levels when mothers were more emotionally available at bedtime, and infants whose mothers responded more often to their non-distressed cues had lower cortisol levels on average. Less co-sleeping and more maternal responses to infant distress were linked to healthier cortisol patterning. By shedding light on parenting qualities and behaviors that influence infant cortisol, these results indicate avenues for intervention and suggest the utility of studying parenting in infant sleep contexts.

Neighborhood Economic Deprivation and Social Fragmentation: Associations With Children's Sleep.

ABSTRACT Background & Objective: A growing body of work indicates that experiences of neighborhood disadvantage place children at risk for poor sleep. This study aimed to examine how both neighborhood economic deprivation (a measure of poverty) and social fragmentation (an index of instability) are associated with objective measures of the length and quality of children’s sleep. Participants: Participants were 210 children (54.3% boys) living predominantly in small towns and semirural communities in Alabama. On average children were 11.3 years old (SD = .63); 66.7% of the children were European American and 33.3% were African American. The sample was socioeconomically diverse with 67.9% of the participants living at or below the poverty line and 32.1% from lower-middle-class or middle-class families. Methods: Indicators of neighborhood characteristics were derived from the 2012 American Community Survey and composited to create two variables representing neighborhood economic deprivation and social fragmentation. Child sleep period, actual sleep minutes, and efficiency were examined using actigraphy. Results: Higher levels of neighborhood economic deprivation were associated with fewer sleep minutes and poorer sleep efficiency. More neighborhood social fragmentation was also linked with poorer sleep efficiency. Analyses controlled for demographic characteristics, child health, and family socioeconomic status. Conclusions: Findings indicate that living in economically and socially disadvantaged neighborhoods predicts risk for shorter and lower-quality sleep in children. Examination of community context in addition to family and individual characteristics may provide a more comprehensive understanding of the factors shaping child sleep.

Sleep and cognitive functioning in childhood: Ethnicity, socioeconomic status, and sex as moderators.

We examined children’s sleep at age 9 as a predictor of developmental trajectories of cognitive performance from ages 9 to 11 years. The effects of sleep on cognition are not uniform and thus we tested race/ethnicity, socioeconomic status (SES), and sex as moderators of these associations. At the first assessment, 282 children aged 9.44 years (52% boys, 65% European American [EA], 35% African American [AA]) participated. Two more waves of data collection spaced 1 year apart followed. The majority of children (63%) were living at or below the poverty line. Children’s sleep was measured objectively with actigraphy and 2 well-established sleep parameters were derived: duration, indexed by sleep minutes between sleep onset and wake time, and quality, indexed by efficiency. Multiple cognitive functioning domains were examined with the Woodcock Johnson Tests of Cognitive Abilities (WJ III). Across the sample, higher sleep efficiency, but not duration, was associated with better cognitive performance. Significant moderation effects emerged. Controlling for SES, AA children scored lower on general intellectual ability and working memory (WM) at age 11 only if they experienced lower sleep efficiency at age 9. Further, boys scored lower on general abilities and processing speed (PS) at age 11 only if their sleep efficiency was lower at age 9. Findings indicate that lower sleep efficiency may contribute to lower cognitive functioning especially for AA children and boys. These vulnerabilities appear to emerge early in development and are maintained over time. Results underscore the importance of individual differences in explicating relations between sleep and children’s cognitive performance.

Marital conflict and trajectories of adolescent adjustment: The role of autonomic nervous system coordination.

The present study investigates how coordination between stress responsivity of the parasympathetic nervous system (PNS) and sympathetic nervous system (SNS) moderates the prospective effects of marital conflict on internalizing and externalizing symptoms across adolescence. Although an important avenue for psychophysiological research concerns how PNS and SNS responses jointly influence adjustment in the context of stress, these processes have rarely been studied in adolescence or longitudinally. Participants were 252 youth (53% female, 66% European American, 34% African American) who participated in laboratory assessments when they were 16, 17, and 18 years old. PNS activity (measured via respiratory sinus arrhythmia [RSA]) and SNS activity (measured via skin conductance level [SCL]) were assessed during a resting baseline and in response to a laboratory-based challenge (star tracing). Parents and adolescents both reported on marital conflict and adolescents reported on their internalizing and externalizing symptoms. At higher levels of marital conflict, coactivation of PNS and SNS activity, characterized by increased RSA and increased SCL from baseline to challenge, predicted elevated internalizing symptoms and an increase in externalizing behavior across adolescence. Coinhibition, or decreased activity across both systems, also predicted an increase in internalizing symptoms over time. At lower levels of marital conflict, internalizing and externalizing symptoms were relatively low. Findings extend primarily cross-sectional work with younger children by demonstrating that coordination between the two branches of the autonomic nervous system (ANS) moderates the longitudinal effects of marital conflict on psychological and behavioral maladjustment among adolescents.

Trajectories of sleep and cardiac sympathetic activity indexed by pre‐ejection period in childhood

Fragmented and insufficient sleep has been implicated in disrupted autonomic nervous system activity during resting state conditions in typically developing children. Towards explication of these relations over development, the current study tested reciprocal relations between the development of sleep parameters (efficiency, duration, latency) and cardiac sympathetic nervous system (SNS) activity indexed by pre‐ejection period (PEP) during waking–resting state conditions throughout middle and late childhood. Whether sleep derives changes in PEP or vice versa was examined. A longitudinal design was employed and latent growth modelling was used to examine the research questions. During the first assessment, 282 children aged 9.44 years (65% European American, 35% African American) participated. Two more assessments followed, with a 1‐year lag between consecutive study waves. Sleep was examined with 7 nights of actigraphy in the childs home. Controlling for many potential confounds (sex, race/ethnicity, body mass index and family socioeconomic status), higher sleep efficiency and more sleep minutes predicted increases in PEP (less SNS activity) over 3 years. PEP did not predict changes in sleep efficiency or duration over time and there were no significant effects for sleep latency. Findings highlight the probable direction of effects between these two key bioregulatory systems. High levels of cardiac SNS activity are associated with many negative health outcomes, and thus these findings may have important implications.

Sleepiness as a pathway linking race and socioeconomic status with academic and cognitive outcomes in middle childhood

Objectives: This study examined self‐reported sleepiness as a pathway of effects underlying racial and socioeconomic disparities in childrens academic and cognitive performance. Design: The study design was longitudinal, and path modeling was used to test study hypotheses. Setting: Data were collected from participants residing in semirural communities and small towns surrounding Auburn, AL. Participants: Children (N = 282; 52% boys) participated in the study when they were 9 (M = 9.44, SD = .71) and 11 (M = 11.33, SD = .69) years old. The sample was 65% White/European American and 35% Black/African American. The majority of the children (63%) were living at or below the poverty line. Measurements: At age 9, children reported on their daytime sleepiness over the prior 2 weeks. At ages 9 and 11, children completed cognitive assessments in the laboratory, teachers reported on childrens academic functioning, and schools provided state (Alabama) standardized test scores. Results: African American children and children from lower socioeconomic status homes reported greater sleepiness. Greater sleepiness, in turn, predicted lower academic functioning, cognitive performance, and Alabama standardized test scores. Sleepiness was a significant intervening variable, but not a mediator, in these pathways. Race was a stronger predictor of sleepiness than socioeconomic status when both were entered in the same model. Conclusions: Results highlight sleepiness as a pathway of effects linking race and socioeconomic status to academic and cognitive outcomes. Psychoeducation targeting sleepiness for African American and lower–socioeconomic status children may be beneficial for boosting achievement.

Approaches to modeling the development of physiological stress responsivity

Influential biopsychosocial theories have proposed that some developmental periods in the lifespan are potential pivot points or opportunities for recalibration of stress response systems. To date, however, there have been few longitudinal studies of physiological stress responsivity and no studies comparing change in physiological stress responsivity across developmental periods. Our goals were to (a) address conceptual and methodological issues in studying the development of physiological stress responsivity within and between individuals, and (b) provide an exemplar for evaluating development of responsivity to stress in the parasympathetic nervous system, comparing respiratory sinus arrhythmia (RSA) responsivity from middle to late childhood with middle to late adolescence. We propose the use of latent growth modeling of stress responsivity that includes time-varying covariates to account for conceptual and methodological issues in the measurement of physiological stress responsivity. Such models allow researchers to address key aspects of developmental sensitivity including within-individual variability, mean level change over time, and between-individual variability over time. In an empirical example, we found significant between-individual variability over time in RSA responsivity to stress during middle to late childhood but not during middle to late adolescence, suggesting that childhood may be a period of greater developmental sensitivity at the between-individual level.

Stability and change in daytime and nighttime sleep in children attending daycare

Many young children experience insufficient or poor quality sleep, which may have implications for adjustment and cognitive performance. This study tested group-level changes and rank-order stability in both daytime and nighttime sleep parameters over a six-month period, from fall to spring, among children receiving high-quality, center-based daycare. A total of 68 preschoolers (54% girls; M age = 3.80 years, SD = .68) participated. Sleep was assessed via actigraphy for seven days and nights; sleep duration (actual sleep minutes) and quality parameters were derived. Analyses of group-level changes indicated that children’s daytime and nighttime sleep duration did not change significantly from fall to spring. Nighttime sleep quality showed significant improvement, however, such that children had higher sleep efficiency in the spring than in the fall. Rank-order stability in both nighttime and daytime measures of sleep duration and quality was moderate, and stability in daytime sleep quality was low. Results add to a sparse literature examining stability in sleep parameters in young children using actigraphy.