Sleep Complaints, Sleep and Breathing Disorders in Myotonic Dystrophy Type 2.

PURPOSE OF REVIEW: To update the current knowledge concerning sleep complaints and breathing disorders in myotonic dystrophy type 2 (DM2) and to better understand if sleep and breathing symptoms may add a further clinical definition of DM2. RECENT FINDINGS: Although DM2 has been poorly evaluated, the most relevant sleep disorders are sleep-disordered breathing (SDB) (37.5-66.7%) and restless legs syndrome (RLS) (50-60%). Excessive daytime somnolence (EDS) is not consistent with SDB, and a large percentage of patients with sleep complaints (58-69%) report pain. In addition, respiratory dysfunctions are reported in 6 to 15% of DM2 patients, albeit few data are available regarding pulmonary restriction, hypoventilation, and non-invasive ventilation (NIV). SDB, RLS, and pain may contribute to sleep fragmentation and EDS in DM2. In addition, few studies report hypoventilation and pulmonary restriction, although there are no studies at all on NIV, except for limited clinical experiences. These findings suggest performing a careful pulmonary examination and NIV when required. Furthermore, sleep studies and respiratory evaluation should be recommended if OSA or respiratory muscle dysfunctions are suspected. A large polysomnographic study should be performed to clarify the link between sleep disorders, pain, and sleep disruption in DM2.