A Family Systems Approach to Sleep Patterns in Down Syndrome

Abstract

Down syndrome (DS) is one of the most common genetic conditions that manifests in a physical, behavioral, mental, emotional, and neurocognitive manner (Bittles, Bower, Hussain, & Glasson, 2006; Bull & the Committee on Genetics, 2011). In terms of physical health, individuals with DS are at a higher risk for congenital heart defects, hypothyroidism, gastrointestinal issues, and sleep problems (Bittles et al., 2006; Carter, McCaughey, Annaz, & Hill, 2009). Of particular importance, is the 30% to 80% prevalence rate of obstructive sleep apnea syndrome (OSAS) in DS (Dyken et al., 2003; Shott et al., 2006). OSAS as well as other sleep disturbances have been linked to neurocognitive and developmental delays among individuals with DS (Breslin et al., 2014; Edgin et al., 2015). A limitation to previous work in DS is evaluating sleep and its impact on development from a family systems perspective. The family’s interconnectedness, cohesiveness, and self-stability characteristics may play a role in sleep and development for individuals with intellectual disability. The three studies presented in this dissertation examined the multiple ways in which sleep effects all members of the family in addition to infant development in a longitudinal sample of infants with and without DS from 6-months to 24-months of age. In Study 1, we investigated work schedules among parents of 18-month-old infants with DS and typically developing (TD) along with its impact on infant sleep quality and quantity. There were no significant differences in work schedules and total number of hours worked per week between parents in both groups. However, infants with DS displayed significantly less sleep time, greater fragmentation index, poorer sleep efficiency, and more time waking up after sleep onset (WASO). We found group differences in nights per week spent co-sleeping and parents’ perceptions regarding the importance of a consistent bedtime routine. When assessing employment schedules, regardless of group, parents who were unemployed were more likely to indicate having an exact bedtime routine for their infant followed by parents with standard and nonstandard work schedules. Parenting stress was significantly higher among parents with a standard work schedule followed by parents with a nonstandard work schedule and unemployed. Finally, we found infant WASO to be highest in the nonstandard work schedule group and unemployed for families with and without DS, respectively. These results highlight the importance of assessing parental work schedules to better understand infant sleep patterns and family functioning. The findings from Study 1 indicate that sleep deficits begin to emerge as early as 18-months among infants with DS. In Study 2, we investigated a specific sleep practice - co-sleeping - and its association with sleep efficiency and daytime regulation among infants with and without DS at 18-months-old. Results indicated that while co-sleeping all of the night is more common among TD infants (approximately 26%), the most common type of co-sleeping for infants with DS was the second part of the night (almost 18%). Infants with DS not only displayed significantly poorer sleep efficiency but also higher scores on the depression/withdrawal subscale of the Infant-Toddler Social and Emotional Assessment (ITSEA) and lower adaptive behavior scores, both signifying delays in socio-emotional outcomes. Co-sleeping frequency was not correlated to sleep efficiency and any of the daytime regulation variables. Nonetheless, these findings suggest a need to assess co-sleeping behaviors in further detail and determine its impact on other sleep parameters and developmental outcomes in children at risk for sleep problems. In the first study, one of the prominent findings involved differing sleep practices between groups, specifically co-sleeping behavior and parents’ perceptions surrounding a bedtime routine. The second study addressed co-sleeping patterns and daytime regulation; therefore, in Study 3 we evaluated the associations between bedtime routine consistency, daytime functioning, and overall sleep quality, relationships not previously studied in this population from 6- to 24-months of age. Findings indicated that parents engaged in a consistent bedtime routine with their infant and their perception of the importance of the routine on their infant’s development increased with time. Growth curve models showed that a consistent bedtime routine was related to less externalizing behavior and fewer vocalizations particularly in the TD group and a 10-point difference in adaptive behavior scores with each assessed time point and longer sleep times regardless of group. Significant group differences were found such that infants with DS displayed less internalizing behavior and poor sleep efficiency compared to TD infants. The results highlight the impact of a consistent bedtime routine for all children, typical and atypical. Altogether, the three papers provide insight into sleep practices that, to our knowledge, have not been studied in the DS population. We note how parent-level factors such as works schedules, decision to co-sleep, and implementing a consistent bedtime routine impact infant sleep behavior. The last study proposes a strength-based approach not deficit-based approach to studying atypical development. Future work should further investigate different factors influencing infant sleep and development while also considering parental sleep behavior to obtain a holistic assessment of sleep among families with DS.