Sleep Disorder Treatments in Muscular Dystrophy Not 'One Size Fits All'

Classifying patients with myotonic dystrophy type 1 (DM1) into 3 sleep disturbance categories will help better target new therapies, a study published in the Journal of Neuromuscular Diseases found.

DM1 is the most common adult muscular dystrophy, and many patients are inflicted with various sleep and respiratory disorders.

“Excessive daytime sleepiness is a common problem for people with myotonic dystrophy, affecting between 33% and 80% of patients,” said lead investigator Dr Sophie D. West, MD. “Other contributing causes can be attributed to poor sleep patterns, obstructive sleep apnea (OSA), respiratory failure, periodic limb movements during sleep, or narcolepsy features.”

From May 2011 to May 2015, patients with DM1 who had symptoms of daytime sleepiness at their annual review at the John Walton Muscular Dystrophy Research Center were referred for an overnight sleep assessment.

The investigators used the Epworth Sleepiness Score (ESS), and found that of the 120 individuals with DM1, 18% had OSA, 27% had respiratory failure, and 30% had intrinsic sleepiness.

The participants were divided into 4 groups: OSA, daytime respiratory failure, ESS, and a control group with no sleep-related symptoms. The treatments were matched to the symptoms, including continuous positive airway pressure (CPAP) for OSA, non-invasive ventilation (NIV) for respiratory failure, and modafinil for excessive daytime sleepiness.

Overall, the results of the study showed only 29% of patients benefited from the therapies and continued them. According to the authors, the result was lower than expected in other patient groups. They suggest that further research needs to be done to determine which DM1 patients are most likely to benefit from targeted therapy and to determine the most effective ways to deliver these therapies to patients with DM1.

The investigators recommend a standard classification of DM1 patients into 3 sleep disturbance types to better target therapies. Patients with high ESS, but no restless leg syndrome or sedative use, should try modafinil. For OSA with no daytime respiratory failure, CPAP should be used. For patients with daytime respiratory failure and an abnormal sleep study, the use of NIV is recommended.

“This is valuable data for those people in the myotonic dystrophy community with excessive sleepiness, to support them in having detailed sleep tests and targeted individualized therapies, hopefully to improve their symptoms,” Dr West concluded.