Down syndrome (DS) is the most common chromosomal disorder with an estimated 250,700 children, teens, and adults living with DS in the United States in 2008 (CDC.gov). The life expectancy for individuals with DS has increased due to improved medical care, educational interventions, and identification and management of underlying psychiatric and behavioral problems. This has resulted in increased median age to 49 years, and the life expectancy of a 1-year-old child with DS to more than 60 to 65 years (Bittles et al. Dev Med Child Neurol. 2004;46[4]:282).

Sleep medicine specialists have been very involved in the care of the pediatric DS population but with the improved survival, more adult patients with DS are presenting to sleep clinics for their care. The complexity of caring for adult patients with DS poses a challenge to sleep specialists, especially with the paucity of literature and clinical guidelines.

OSA is more prevalent in children with DS (30% to 55%) compared with control subjects (2%). This high OSA prevalence further increases to 90% in adults with DS and is associated with more oxygen desaturation, hypoventilation, and sleep disruption (Trois et al. J Clin Sleep Med. 2009;5[4]:317). Childhood risk factors for OSA in DS are mostly related to hypotonia, relatively large tongue, tonsillar and adenoid hypertrophy, and the small airway. Obesity, hypothyroidism, and, more importantly, advancing age contribute to the increased risk of OSA in adults with DS. Central sleep apnea is relatively rare in adults with DS (Esbensen. Int Rev Res Ment Retard. 2010;39(C):107).

A bidirectional relationship exists between sleep disorders and mood and cognitive problems in this population. The frequency of OSA diagnosis is increased in adults with DS who present with new-onset mood disorder or declining adaptive skills (Capone et al. Am J Med Genet A. 2013;161A[9]:2188). OSA in DS is associated with sleep disruption, decreased slow wave sleep, and intermittent hypoxemia that are thought to contribute to the mechanism of declining cognitive function and memory. Given that individuals with DS are genetically at increased risk for diffuse senile plaque formation in the brain (a characteristic pathologic finding in Alzheimer’s disease brain), the super-imposed sleep fragmentation and intermittent hypoxia may accelerate the cognitive decline (Fernandez et al. J Alzheimers Dis Parkinsonism. 2013;3[2]:124).

In addition, sleep in adults with DS is characterized by a high incidence of sleep fragmentation and circadian misalignment with delayed sleep onset and early morning awakenings (Esbensen. J Intellect Disabil Res. 2016;60[1]:68). The DS population is also at increased risk for developing depression, anxiety, obsessive-compulsive tendencies, and behavioral issues. It is also worth noting that there is a tenfold increase in autism spectrum disease in this population, and a rare condition of developmental regression in adolescents with DS has recently been recognized. Patients usually present with rapid, atypical loss of previously attained skills in cognition, socialization, and activities of daily living that may further complicate their care. The regression occurs with maladaptive behaviors that develop in relation to new transitions, hormonal or menstrual changes, or major life events (Jensen et al. Br Med J. 2014;349:g5596). As a result, new behavioral sleep problems may emerge, or challenges to the treatment of existing sleep disorders may ensue. All of the aforementioned conditions alone or in combination pose additional challenges for the management of sleep problems in this population.

Adults with DS continue to manifest the same spectrum of health problems as children with DS. Adults with DS also tend toward premature aging, which puts them at risk for additional health problems seen in the geriatric population (Covelli et al. Int J Rehabil Res. 2016;39[1]:20). Adults with DS will age earlier and two times faster than control subjects (Nakamura et al. Mech Ageing Dev. 1998;05:89). Coexisting obesity and worsening cognitive function that further increase after the age of 40 will make multiple aspects of medical management very challenging (Carfi et al. Front Med. 2014;1:51).

The care of the adult patient with DS can be best delivered through a multidisciplinary team, led by physicians well informed about the specific needs of this population. The role of the sleep specialist is essential, given the implications of sleep on health and cognitive and behavioral function. The approach to diagnosing disorders of sleep timing, quality, and duration includes a focused history. Incorporating actigraphic monitoring provides additional information that can be relevant and useful. The value of the parent-reported sleep diary becomes less and less reliable as patients enter adolescence and adulthood. Attended sleep studies are widely utilized for diagnosing sleep-disordered breathing, but their value in guiding therapy is debatable. There are multiple factors that can affect the validity of a single night of sleep testing for the individual patient. Such factors include poor sleep achieved in a strange environment and sleep position variations when compared with sleep at home. There is no evidence yet to support the use of portable sleep testing in this population.

Establishing and maintaining routines are critical in different aspects of the care of this special population, particularly in relation to behavioral sleep problems. Success is dependent on the caregiver’s approach and level of involvement in their care, the individual’s intellectual ability, and the presence of other comorbidities. Management of obesity with counseling on healthy diet and participation in exercise programs are also integral parts of their care.

Although treatment with positive airway pressure (PAP) is thought to be effective in treating OSA in DS, little data are available to support its efficacy and benefits. Treatment of OSA with PAP can be very challenging. Our sleep center experience incorporates a personalized approach with gradual PAP desensitization in addition to positive feedback and a reward system to encourage and maintain use. We also utilize behavioral therapy to encourage avoidance of supine sleep in order to decrease the severity of OSA in patients who do not accept or tolerate PAP. Surgical interventions based on assessment of the upper airway during sleep through dynamic imaging or sleep endoscopy may also be considered. A recent report of hypoglossal nerve stimulation therapy in an adolescent with severe OSA suggests a potentially new alternative option for therapy (Diercks et al. Pediatrics. 2016;137(5). doi: 10.1542/peds.2015-3663.

It seems intuitive that the management of sleep disorders in adult patients with DS positively contributes to their care and promotes their overall wellbeing. Adult patients with DS continue to present particular diagnostic and therapeutic challenges that have become even more complex as their life expectancy has increased. Further research and clinical guidelines are momentously needed in order to guide the management of sleep disorders for this particularly challenging patient population.

Dr. Shaib is Associate Professor of Medicine, Medical Director, Baylor St Luke’s Center for Sleep Medicine, Department of Medicine, Section of Pulmonary, Critical Care, and Sleep Medicine, Baylor College of Medicine, Houston, Texas.

Sleep Strategies: Sleep in adults with Down syndrome