Psychosocial Risk Factors Identified During the Child and Adolescent Crisis Care Program Intervention.

The circadian system regulates nearly all physiological and behavioral processes including the sleep-wake cycle and cognitive function. These processes are highly rhythmic and regulated by a central pacemaker in the suprachiasmatic nucleus of the hypothalamus, approximating 24-hour oscillations or circadian rhythms ( = about, = day). Consequently, circadian disruption can lead to fragmentation of the 24-hour rest-activity rhythm, which has been shown to increase the risk of adverse health outcomes including cognitive impairment and Alzheimer disease (AD) dementia. A growing number of studies have used actigraphy to evaluate the 24-hour rest-activity rhythm and cognitive outcomes in the general population. For example, in older adults, rest-activity fragmentation was associated with deficits in perceptual speed, semantic and working memory, and visuospatial tasks. Longitudinal studies show that fragmentation and lower amplitude of the 24-hour rest-activity rhythm are associated with a higher incidence of mild cognitive impairment (MCI) and dementia. In addition, sleep-wake timing and sleep-wake regularity (day-to-day stability of sleep-wake patterns) are associated with cognitive function. Adults with DS have a >90% lifetime risk of AD dementia because of the triplication of the amyloid precursor protein (APP) gene located on chromosome 21. Although the mean age at onset is 53.8 years, variability in the age at onset is large, indicating that a potential modifiable factor such as circadian disruption could be influencing the development and progression of AD dementia. Sleep-wake disturbances are highly prevalent in adults with DS. Compared with the general population, adults with DS have poor sleep efficiency, increased wake after sleep onset, and decreased nightly total sleep time with increased daytime napping. Although obstructive sleep apnea (OSA) is highly prevalent in individuals with DS, there is evidence suggesting that OSA alone does not fully account for these disturbances. Circadian and sleep dysregulation likely contribute to the disturbances but their role on cognitive function in adults with DS is poorly understood.