Weakened respiratory and upper airway muscles caused by neuromuscular disorder can cause insufficient breathing during sleep in both adults and children, leading to increased risk of obstructive sleep apnea (OSA). During obstructive OSA, a person has reduced air flow or stops breathing. In order to start breathing again, a person wakes up briefly sometimes hundreds of times per night. Often, the person does not remember waking.

Breathing difficulties may not be obvious during the day, but can significantly worsen during sleep, particularly during REM (dreaming) sleep. Symptoms of insufficient breathing during sleep include daytime fatigue, poor sleep quality, nightmares and headaches. OSA is caused by biomechanical issues such as the airway collapse and/or lack of muscular strength in the muscles related to breathing. In children, OSA may be associated with enlarged tonsils and/or adenoids.

The cause for another type of sleep apnea, central sleep apnea, occurs in the brain. Some individuals have sleep apnea that is caused by both obstructive and central nervous system factors, called mixed sleep apnea.

Obstructive sleep apnea often affects individuals with neuromuscular diseases, including congenital myasthenic syndromes, and muscular dystrophy. For example, researchers have shown that individuals with myasthenia gravis have a higher likelihood of OSA than individuals in the general population. Without proper diagnosis and treatment, these patients may experience fatigue leading to overmedication without effective treatment of the cause of fatigue.

Despite the importance of sleep, physicians may not address sleep and sleep-related breathing. Daytime fatigue and tiredness may be assumed to be caused by neuromuscular disease rather than sleep disorder. Further, OSA may not cause daytime symptoms at all.

Signs of sleep apnea include difficulty falling asleep or staying asleep, restlessness, nighttime sweating, dry mouth, headaches upon wakening, and fatigue and tiredness during the day. Problems may be noticed by a bed partner or caretaker, including loud snoring, gasping for breath, periods of decreased or absent breathing, or restlessness. An overnight sleeping test, called polysomnography, can be used to reveal the presence of sleep apnea.

Once OSA is detected, effective treatment exists. The most common treatment for OSA includes assistance with ventilation such as bilevel positive airway pressure ventilation which has been found to be effective for individuals with neuromuscular disease. Changes in sleeping position may also be considered, as OSA often worsens when individuals with OSA sleep on their back. In children with enlarged tonsils and/or adenoids, surgery may be considered. Appropriate treatment may be different in someone with a neuromuscular disease than in the general population: Make sure that your sleep physician knows your diagnosis.

Sleep impacts a person’s physical, cognitive, and emotional health. Untreated sleep apnea leads to significant problems with health and quality of life. Poor sleep can worsen daytime functioning and increase disability in those with neuromuscular disease. More specifically, untreated OSA has been associated with cardiac and metabolic problems, daytime fatigue, problems with memory and concentration, and increased chance of vehicle accidents. In children, untreated OSA is also associated with poor academic performance, failure to thrive, behavioral disorder, and bedwetting.

About 40% of those with neuromuscular disease suffer from some type of sleeping disorder. Given the importance of sleep to your health, make sure to discuss any sleep problems with your physician. Getting treatment for sleep apnea and other sleep problems can improve your sleep, health, and quality of life.

Resources:
Chan, J., et al., Obstructive Sleep Apnea in Children. American Family Physician, 69(5). Available at https://www.aafp.org/afp/2004/0301/p1147.html .
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Guilleminault, C., et al., (1998). Sleep and neuromuscular disease. Journal of Neurology and Neurosurgery in Psychiatry, 65(2): 225-32. Abstract available at https://www.ncbi.nlm.nih.gov/pubmed/9703177 .
Labbe, A., (2008). Not Enough ZZZzzzs? Quest, 15:2. https://quest.mda.org/article/not-enough-zzzzzzs .
MDA,(2006). Undiagnosed Sleep Apnea in MG Could Lead to Overmedication. https://www.mda.org/research/060927mg_sleep_apnea.html .
MDA,(2009). Breathe Easy: Respiratory Care in Neuromuscular Disorders. https://static.mda.org/publications/breathe/ .
MDA,(2009). Myotonic Muscular Dystrophy. https://www.mda.org/disease/myotonic-muscular-dystrophy .
MDA,(n.d.). Congenital Myasthenic Sydromes: Signs and Symptoms. https://mda.org/disease/congenital-myasthenic-syndromes/signs-and-symptoms .
Oztura, I., et al.,(2005). Neuromuscular Disorders and Sleep. Current Neurology and Neuroscience Reports, 5, pp 147-152.
Suresh, S., et al., (2005). Sleep-related breathing disorder in Duchenne muscular dystrophy. Journal of Paediatrics and Child Health, 41:9/10, pp 500-503.