Self-Reported Sleep Quality and Sleep Disordered Breathing in Chronic Spinal Cord Injury: More than a Snore
Assessment of secondary complications accompanying SCI.
A web-based survey, sleep questionnaires, and in-lab polysomnography examined sleep quality, sleep habits, excessive daytime sleepiness, and risk/prevalence for sleep disordered breathing (SDB) in persons with chronic SCI. Survey-derived sleep complaints/ disorders were prevalent after SCI, and may compromise physical/cognitive well-being Polysomnography reveals an extremely high prevalence of SDB.
Rationale: Disorders of sleep are often considered a routine annoyance of daily life, yet are now significantly associated with, and commonly considered a forerunner to, cardiometabolic diseases (CMDs). As CMDs and their risk components are frequently associated with spinal cord injuries, sleep disorders may represent a potential antagonist to psychological well-being, cognitive acuity, and physical health. Thus, a web-based survey, sleep questionnaires, and in-lab polysomnography were used to examine sleep quality, sleep habits, prevalence of excessive daytime sleepiness (EDS), and risk/prevalence for sleep disordered breathing (SDB) in participants with chronic (> 1 year) SCI. Methods: The survey was accessible from March 2011 on the worldwide web, and advertised through SCI consumer organizations in the United States, Australia, New Zealand, and Canada. Epworth Sleepiness Score (ESS), Berlin Sleep Questionnaire, Sleep Quality, Sleep Habits Questionnaire, general health, and demographic questions were included. The survey targets 500 respondents. In-lab polysomnography was completed on 19 study participants. Results: To date, 183 individuals with SCI have completed the survey. Participants were; age 45.4 ± 12.9 (mean ± s.d.) years, BMI 24.04± 4.9 kg/m2, 78.7% white, 5.1% Black, 1.7 Asian, and 12.9% Latino. They were highly educated, with 48.9% reporting a college or professional degree; 37.7% were part-time or full-time employed, 18% were retired, and 46.1% were married. The mean time from injury was 15.1 ± 10.8 years, with 52.8% reporting SCI at a cervical level. The mean self-reported total sleep time (major sleep period) during weekdays was 6.6± 1.6 hours, and on weekends was 7.1 ± 1.9 hours. Insomnia symptoms during the preceding month were reported as ‘often’ or ‘almost always’ having difficulty with the following: sleep initiation (37.1%), sleep maintenance (37.7%), early morning rising (29.7%), and non-refreshing sleep (42.9%). EDS, defined by ESS ≥ 10, was reported by 30% of the population, while 38% ranked their sleep quality as ‘fairly bad’ to ‘very bad’ in the preceding month. Overall, 33% of the population was at high risk for SDB. In polysomnography studies EDS was reported by 32% of participants, 32% were high risk for SDB (based on Berlin screening tool), and 47% reported poor sleep quality (Pittsburgh Sleep Quality Index [PSQI] >=6). 74% of participants had objective clinical evidence of SDB when undergoing in-lab polysomnography (Apnea-Hypopnea Index [AHI]HI >=5) with a mean AHI of 17 ± 15. Conclusions: Sleep complaints and disorders are prevalent in individuals with SCI and may play an important role in compromising physical and cognitive well-being. Polysomnography reveals an extremely high prevalence of SDB. Studies are underway to further characterize potential causes for SDB, associations with CMD, and the utility of nocturnal positive airway pressure as a countermeasure to both SDB and CMD risks accompanying SCI.