Multiple Sclerosis (MS) is a chronic disease of the central nervous system (CNS) that disrupts the flow of information within the brain and body. MS involves the immune system mistakenly attacking the protective covering of nerve fibers (demyelination), which leads to scarring. Sleep Apnea (SA) is a separate breathing disorder characterized by repeated pauses in breathing during sleep, causing fragmented rest and decreased oxygen levels. Research indicates a significant relationship between the two, suggesting that MS can contribute to the development of sleep apnea. This connection highlights a potentially treatable factor that may be worsening symptoms for many people living with MS.
The Epidemiological Link Between MS and Sleep Apnea
The prevalence of sleep apnea among individuals with multiple sclerosis is significantly higher than in the general population. Research consistently shows a strong co-morbidity, with some studies suggesting that up to 50% of MS patients may suffer from Obstructive Sleep Apnea (OSA). This elevated risk exists even when accounting for typical risk factors for sleep apnea, such as age and body weight.
The high frequency of sleep apnea suggests that the neurological disease itself plays a direct or indirect role in its development. Sleep apnea in MS patients is associated with worse outcomes, including increased fatigue and accelerated cognitive decline. Successfully treating the sleep disorder can potentially improve these debilitating symptoms, which are often mistakenly attributed solely to the MS disease process. Therefore, screening for sleep-disordered breathing is important for every individual diagnosed with MS.
Neurological Mechanisms of Sleep Disruption
The direct link between multiple sclerosis and sleep apnea is rooted in the location of demyelinating lesions within the central nervous system. MS can cause both major types of sleep apnea: Central Sleep Apnea (CSA) and Obstructive Sleep Apnea (OSA). CSA occurs when the brain fails to send necessary signals to the breathing muscles, resulting in no respiratory effort during an apneic event.
MS-related lesions that form in the brainstem are the primary cause of CSA in this population. The brainstem houses the respiratory control centers that regulate the drive to breathe and maintain upper airway muscle tone during sleep. Demyelination in this region disrupts these pathways, leading to a failure of respiratory effort. Studies show that MS patients with brainstem lesions exhibit significantly higher central apnea indices.
Obstructive Sleep Apnea (OSA), which is far more common, results from the physical collapse of the upper airway despite the brain’s continued signal to breathe. While often related to anatomical features, MS contributes to OSA through neuromuscular weakness. Lesions affecting the nerves that control the upper airway muscles can lead to insufficient muscle tone during sleep. Additionally, the general muscle weakness and fatigue experienced by many MS patients may indirectly worsen the severity of an existing obstructive component.
Recognizing Sleep Apnea Symptoms in MS Patients
Identifying sleep apnea in individuals with multiple sclerosis can be a diagnostic challenge due to the high degree of symptom overlap. The most common consequence of sleep apnea is excessive daytime fatigue and sleepiness. Since debilitating fatigue is also a prevalent symptom of MS, affecting up to 90% of patients, sleep apnea symptoms are often masked or incorrectly attributed to the underlying MS.
Common signs of sleep apnea include loud, habitual snoring and observed pauses in breathing during the night. Individuals might also wake up gasping or choking, or experience non-restorative sleep, meaning they wake up feeling unrefreshed. Morning headaches are another frequent symptom that should prompt a discussion with a healthcare provider.
Patients should also be aware of signs of brainstem dysfunction, such as difficulty with swallowing (dysphagia) or speaking (dysarthria), as these indicate a higher risk for both OSA and CSA. Because sleep apnea symptoms closely mirror MS-related fatigue and cognitive impairment, healthcare providers should maintain a low threshold for evaluation. Failure to recognize and treat sleep apnea can exacerbate cognitive difficulties and reduce the overall quality of life for the patient.
Diagnosis and Management Strategies
The definitive diagnosis of sleep apnea requires a formal sleep study, even in patients with multiple sclerosis. Polysomnography (PSG) is the most comprehensive type, performed overnight in a sleep laboratory to monitor brain activity, oxygen levels, heart rate, and breathing patterns. While at-home tests screen for Obstructive Sleep Apnea, in-laboratory PSG is preferred for MS patients because it is more effective at detecting Central Sleep Apnea (CSA), a specific concern for this population.
For management, Positive Airway Pressure (PAP) therapy is the standard first-line treatment for both types of sleep apnea. Continuous Positive Airway Pressure (CPAP) delivers a constant stream of pressurized air to keep the airway open during sleep. Bi-level Positive Airway Pressure (BiPAP) is sometimes used, delivering different pressures for inhalation and exhalation, which may be easier to tolerate.
When prescribing PAP therapy, the medical team must consider the patient’s existing neurological deficits. MS-related symptoms like hand tremors, muscle weakness, or dexterity issues can make handling the mask or cleaning the equipment challenging. Specialized mask interfaces and adaptive equipment may be necessary to ensure treatment compliance. Lifestyle adjustments, such as maintaining a healthy weight and avoiding alcohol before bed, can also help reduce sleep apnea severity.