Sleep disorders in myotonic dystrophy type 2: a controlled polysomnographic study and self-reported questionnaires

Area of Science:

• Neurology
• Sleep Medicine
• Genetic Disorders

Background:

• Limited data exists on sleep disorders in myotonic dystrophy type 2 (DM2).
• Sleep disturbances are common in neuromuscular disorders.
• Understanding sleep in DM2 is crucial for patient management.

Purpose of the Study:

• To investigate the sleep-wake cycle and daytime sleepiness in DM2 patients.
• To compare sleep patterns in DM2 with DM1 patients and healthy controls.
• To identify prevalent sleep disorders in DM2.

Main Methods:

• Recruited 12 DM2 patients, 12 healthy controls, and 18 DM1 patients.
• Assessed subjective sleep quality using the Pittsburgh Sleep Quality Index (PSQI).
• Evaluated excessive daytime sleepiness (EDS) with Epworth Sleepiness Scale and Daytime Sleepiness Scale.
• Conducted 48-hour polysomnography and Multiple Sleep Latency Test.

Main Results:

• All 12 DM2 patients had sleep efficiency <90%, significantly lower than controls and DM1.
• Sleep-disordered breathing (7/12) and periodic limb movements of sleep (3/8) were common in DM2.
• Six DM2 patients exhibited REM sleep without atonia; none in controls or DM1.
• DM2 patients reported poorer sleep quality (higher PSQI scores) than controls and DM1.

Conclusions:

• Sleep quality is significantly poorer in DM2 patients compared to DM1 patients and healthy controls.
• Sleep apnea is the most prevalent sleep disorder in DM2.
• Obstructive sleep apnea and sleep fragmentation likely cause EDS in DM2.
• Periodic limb movements of sleep (PLMS) are a frequent finding in DM1.