How common are sleep disturbances in multiple sclerosis? 1

Sleep disruption and sleep-disordered breathing (repetitively stopping breathing or insufficient breathing during sleep), may be important factors in the management of multiple sclerosis (MS). MS is a chronic autoimmune disease of the central nervous system. Types of sleep-disordered breathing include obstructive sleep apnea and central sleep apnea. Obstructive sleep apnea occurs when breathing efforts continue but the upper airway becomes severely narrowed or blocked during sleep, limiting airflow. In central sleep apnea, the drive to breathe from the brain is impaired. Both obstructive and central sleep apnea result in low oxygen levels and adverse health outcomes. MS and sleep-disordered breathing are examples of motor impairment and when combined can be problematic.  Indeed, recent findings have shown a potential link between sleep-disordered breathing and fatigue, a very common and debilitating symptom in MS (Veauthier et al. 2011). Sleep-disordered breathing and sleep disturbance also worsen cognitive function in MS (Braley et al. 2016). Furthermore, treating obstructive sleep apnea may reduce fatigue and improve cognition in MS (Veauthier et al. 2013). Therefore, sleep disruption may be an important modifiable factor contributing to fatigue and impaired cognition in MS. To date, the extent of sleep disruption and symptoms of sleepiness in MS have not been well characterised. Further, it is not clear if home sleep testing is well tolerated in this population. Accordingly, this pilot study aimed to investigate sleep-disordered breathing and perceived sleep quality and sleepiness in a clinical cohort of 21 MS patients. We used a home sleep study device to look for the presence of obstructive sleep apnea and central sleep apnea, and used validated questionnaires to assess sleep quality, sleepiness, and its impact.

WHAT DID WE FIND?

We found a higher than expected rate of central sleep apnea in 16% of our cohort. Central sleep apnea might occur in the context of MS, as MS may damage areas of the brain that control breathing. Excessive daytime sleepiness and poor sleep quality was common, at 33% and 71% respectively, reinforcing that these are important issues for MS patients. We also found that home sleep studies were well tolerated by our cohort, indicating that home testing is feasible in the MS population.

SIGNIFICANCE AND IMPLICATIONS

The higher than expected rate of central sleep apnea found has potential implications for the management of patients with MS. Like obstructive sleep apnea, central sleep apnea might be linked with fatigue in people with MS. Perhaps treating central sleep apnea will reduce fatigue in MS, however further studies will be needed to determine this effect. Our findings will also help inform future studies aimed at characterising and understanding the causes and manifestations of sleep disordered breathing and its impact in people with MS.

PUBLICATION

Lin M, Krishnan AV, Eckert DJ (2016). Central sleep apnea in multiple sclerosis: a pilot study. Sleep Breath. Epub ahead of print. DOI: 10.1007/s11325-016-1442-9.

KEY REFERENCES

Braley TJ, Kratz AL, Kaplish N, Chervin RD (2016). Sleep and Cognitive Function in Multiple Sclerosis. Sleep 39(8): 1525-1533.

Veauthier C, Gaede G, Radbruch H, Gottschalk S, Wernecke KD, Paul F (2013). Treatment of sleep disorders may improve fatigue in multiple sclerosis. Clin Neurol Neurosurg 115(9): 1826-1830.

Veauthier C, Radbruch H, Gaede G, Pfueller CF, Dörr J, Bellmann-Strobl J, Wernecke KD, Zipp F, Paul F, Sieb JP (2011). Fatigue in multiple sclerosis is closely related to sleep disorders: a polysomnographic cross-sectional study. Mult Scler 17(5): 613-622.