Systematic Review Reveals Poor Sleep Quality in Neuromyelitis Optica Spectrum Disorder

Published in the International Journal of MS Care, a systematic review revealed significantly poorer sleep quality among patients with neuromyelitis optica spectrum disorder (NMOSD) than controls.¹ This finding suggests sleep disturbances are a major contributor to the disease burden and may arise from the disruption of sleep circuitry, in addition to physical and psychological complications.

Among 13 studies including 1041 patients with NMOSD, a consistent and significant pattern of disturbed sleep was demonstrated across subjective metrics based on patient surveys and objective metrics such as polysomnography. In the review, investigators observed that an estimated 70% of patients with NMOSD from the studies could be classified as poor sleepers.

“The main implication is that patients with NMOSD have abnormal sleep patterns and should have sleep study performed,” senior author Edward Margolin, MD, FRCS(C), full professor at the department of ophthalmology and visual sciences and department of neurology at the University of Toronto Faculty of Medicine, told NeurologyLive®. “Further research is needed but most importantly treating clinicians should be aware of the fact that patients with NMOSD have abnormal sleep and as sleep is a fundamental part of our overall well-being, this should be addressed/thought of.”

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Investigators conducted a literature search using Ovid MEDLINE, Embase, and Scopus databases between inception and September 3, 2020. All the studies included in the review reported at least 1 measure of sleep quality in patients with NMOSD. The researchers compared the Pittsburgh Sleep Quality Index (PSQI) scores of patients from 4 studies (n = 183) with those from a data set of controls (n = 9284).2-5

In these studies, the standardized mean difference between PSQI scores of patients with NMOSD and those of controls was 0.72 (95% CI, 0.57-0.86; P <.001). Investigators observed that decreased sleep quality was significantly associated with decreased quality of life and increased anxiety, depression, and disability status among patients with NMOSD. Additionally, authors observed that sleep disturbances among the patients with NMOSD were similar in severity to those in patients with multiple sclerosis.

“It is possible that damage to circadian circuity, direct effects of inflammation, aminergic projecting system abnormalities, glymphatic system impairment caused by NMOSD autoantibodies, and development of sleep disorders underlie the observed sleep pathologies,” Margolin and colleagues wrote.¹ “Targeted treatments must address specific sleep abnormalities in this population to avoid broad therapies that may not specifically address the specific sleep problem in an individual patient.”

The number of studies included in the review and variability among measuring tools used were limited, which made it difficult for the investigators to precisely assess the magnitude of sleep deficits in patients with NMOSD. Another limitation of the review was that none of the studies compared the relative contribution of each of the aforementioned factors with poor sleep and only 2 studies evaluated the prevalence of pain on sleep. In addition, the studies did not assess the impact of disease localization or lesion burden on sleep quality and did not compare differences in sleep quality in patients with and without AQP4 antibodies.

“The pathophysiology of NMOSD and its relationship to sleep is multifaceted and complex. Certain pathologic processes may uniquely occur in each patient, causing a large spectrum of sleep disorders, ranging from normal sleep to chronic insomnia to symptomatic narcolepsy. It is still unclear what factors are driving poor sleep in NMOSD,” Margolin et al noted.¹ “Ultimately, although there are many theorized causes of poor sleep in NMOSD, the most likely explanation involves a combination of many of these factors.”

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REFERENCES
1. Eshtiaghi A, Eapen-John D, Zaslavsky K, Vosoughi R, Murray BJ, Margolin E. Sleep Quality in Neuromyelitis Optica Spectrum Disorder: A Systematic Review. Int J MS Care. 2022;24(3):124-131. doi:10.7224/1537-2073.2021-019
2. Miao X, Shi Z, Chen H, Zhou H, Yang R. The impact of pain, anxiety and depression on sleep quality in Chinese patients with neuromyelitis optica spectrum disorders. Neurol Asia. 2017; 22(3): 235–241.
3. Shi Z, Chen H, Lian Z, Liu J, Feng H, Zhou H. Factors that impact health-related quality of life in neuromyelitis optica spectrum disorder: anxiety, disability, fatigue and depression. J Neuroimmunol. 2016;293:54-58. doi:10.1016/j.jneuroim.2016.02.011
4. Song Y, Pan L, Fu Y, et al. Sleep abnormality in neuromyelitis optica spectrum disorder. Neurol Neuroimmunol Neuroinflamm. 2015;2(3):e94. Published 2015 Apr 16. doi:10.1212/NXI.0000000000000094
5. Seok JM, Choi M, Cho EB, et al. Fatigue in patients with neuromyelitis optica spectrum disorder and its impact on quality of life. PLoS One. 2017;12(5):e0177230. Published 2017 May 23. doi:10.1371/journal.pone.0177230