Study Objectives: The prevalence of obstructive sleep apnea (OSA) in persons with multiple sclerosis (MS) remains unknown, and little information exists regarding the relative contributions of OSA to symptoms of MS-related fatigue in the presence of other clinical and sleep-related confounders. The objectives of this study were to investigate the prevalence of diagnosed OSA and OSA risk among MS patients, and to assess relationships between fatigue severity, OSA, OSA risk, and sleep quality among persons with MS. Methods: N = 195 MS patients completed a questionnaire comprised of items regarding OSA diagnosis, sleep quality and quantity, daytime symptoms, and 4 validated scales: the Epworth Sleepiness Scale, Fatigue Severity Scale, Insomnia Severity Index, and STOP-Bang questionnaire. Medical records were also accessed to examine clinical characteristics that may predict fatigue or OSA risk. Results: N = 41 patients (21%) carried a formal diagnosis of OSA. N = 110 (56%) of all patients, and 38 (93%) of those with diagnosed OSA had STOP-Bang scores ≥ 3, indicating an elevated OSA risk. In regression models, the most signifi cant predictors of higher FSS scores were higher STOP-Bang scores (p = 0.01), higher number of nocturnal symptoms (p < 0.0001), and higher disability level (p < 0.0001). Conclusions: Sleep disturbances, and OSA in particular, may be highly prevalent yet underrecognized contributors to fatigue in persons with MS.
S C I E N T I F I C I N V E S T I G A T I O N SM ultiple sclerosis (MS) is an autoimmune disease of the central nervous system that causes myelin destruction and axonal damage in the brain and spinal cord. Multiple sclerosis is the leading cause of non-traumatic neurological disability among young adults, and is associated with a variety of debilitating symptoms, including fatigue.Fatigue affects up to 90% of multiple sclerosis patients at some point during their disease course.1-4 This highly debilitating symptom imposes signifi cant socioeconomic consequences 5 and is a leading cause of diminished quality of life among individuals with MS.3 Although MS-related fatigue is often multifactorial, identifi cation of treatable causes that may contribute to its severity is an essential element of management of this symptom.Obstructive sleep apnea (OSA) may exacerbate fatigue severity in MS. This treatable disorder of sleep and breathing is a known cause of fatigue and related symptoms in general population studies, 6 and constitutes a signifi cant risk factor for cardiovascular disease, metabolic syndrome, motor vehicle accidents, reduced productivity, cognitive dysfunction, and poor quality of life.7-14 Yet, despite its impact in the general population, the extent to which OSA contributes to fatigue in persons with MS is poorly understood, and the prevalence of OSA in MS remains unclear. Whereas some contend that the prevalence of OSA is higher in MS patients than in the general population, heterogeneity in subjects studied, sample sizes, and outcome measures have led to highly variable e...