Sleep-Related Breathing Disorders in Multiple Sclerosis: Prevalence, Features and Associated Factors

Background: Multiple sclerosis (MS) represents a risk factor for sleep disorders, but there are conflicting results about the prevalence and severity of sleep-related breathing disorders (SRBD) in MS. Most available data come from self-administered questionnaires. Objective: To conduct a polysomnographic study in MS focused on SRBD, compared to a group of healthy controls (HC), also considering the neuroimaging findings. To evaluate the impact of SRBD on vigilance, fatigue and depression in MS. Methods: In this cross-sectional, observational, instrumental study, 67 MS patients (men/women: 20/47; mean age: 50.6 +/- 8.2 years) underwent PSG and maintenance of wakefulness test. Findings were compared to 67 age-, sex-, BMI-matched HC, by using parametric (Student's t-test) and nonparametric statistics (chi-squared test). A subgroup analysis was then performed, evaluating the influence of brainstem (mesencephalic, pontine and medullary) lesions at neuroimaging on instrumental and clinical data: MS patients with at least one brainstem lesion vs MS patients without vs HC. Results: The frequency of SRBD was comparable in MS patients and HC. No MS patient had a central apnea index >= 2/h. The respiratory disturbance index (RDI) did not correlate to clinical parameters such as fatigue and depression. Patients with MS were drowsier than HC (47% vs 26%, p = 0.019) and showed a worse sleep pattern, in terms of duration, efficiency and architecture. Conclusion: Our study does not provide evidence of an association between MS-specific symptoms such as fatigue, sleepiness, depression and central or obstructive apneas, even in the presence of brainstem lesions.