Assessing Sleep Disorders in Neuromyelitis Optica Spectrum Disorder: A Comparison of Qualitative and Quantitative Approaches

Abstract

Objectives: This study aimed to: 1) evaluate the macrostructure of sleep and identify the presence of sleep disorders such as hypersomnia, fatigue, apnea risk, and restless legs syndrome (RLS) in neuromyelitis optica spectrum disorder (NMOSD) patients, using both questionnaires and quantitative tests; 2) assess the correlation between the data from these questionnaires and quantitative tests in NMOSD patients, and predict which patients may require further investigation. Methods: The study population comprised 26 consecutive NMOSD patients, along with a control group of 20 healthy volunteers. Polysomnography (PSG) and the Multiple Sleep Latency Test (MSLT) were conducted, along with the administration of various questionnaires, including the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepinesss Scale (ESS), STOP-Bang scale, RLS diagnostic questionnaire, RLS Severity Scale, and the Beck Depression Inventory (BDI). These assessments were performed prospectively to evaluate sleep quality, daytime sleepiness, the detection of obstructive sleep apnea syndrome (OSAS), the presence of RLS, the severity of RLS, and the presence of depressive symptoms. Results: An increase in the NREM1 ratio was observed in NMOSD patients compared to healthy controls, with higher values for total apnea hypopnea index (AHI), REM AHI, and NREM AHI, while the minimum O2 saturation was lower. However, no significant differences were observed between the groups regarding sleep efficiency, periodic legs movement (PLM) index, arousal index, sleep latency, and REM latency. According to the MSLT data analysis, we found that sleep latency was shorter, and hypersomnia/narcolepsy occurred more frequently. There was no significant difference in the STOP-Bang score between the two groups. The ESS score, PSQI score, presence of RLS, and body mass index (BDI) score were significantly higher in the patient group. Conclusion: Our findings suggest that the macrostructure of sleep is significantly impacted in NMOSD patients, with a higher prevalence of OSAS, hypersomnia/ narcolepsy, and RLS. To enhance the quality of life in these patients, it is crucial to investigate sleep disorders early using qualitative methods and to implement appropriate treatments at an early stage.