title: Restless legs syndrome and daytime sleepiness are prominent in myotonic dystrophy type 2.
abstract: OBJECTIVE
  Although sleep disturbances are common in myotonic dystrophy type 1 (DM1), sleep disturbances in myotonic dystrophy type 2 (DM2) have not been well-characterized. We aimed to determine the frequency of sleep disturbances in DM2.
  
  
  METHODS
  We conducted a case-control study of 54 genetically confirmed DM2 subjects and 104 medical controls without DM1 or DM2, and surveyed common sleep disturbances, including symptoms of probable restless legs syndrome (RLS), excessive daytime sleepiness (EDS), sleep quality, fatigue, obstructive sleep apnea (OSA), probable REM sleep behavior disorder (pRBD), and pain. Thirty patients with DM2 and 43 controls responded to the survey. Group comparisons with parametric statistical tests and multiple linear and logistic regression analyses were conducted for the dependent variables of EDS and poor sleep quality.
  
  
  RESULTS
  The mean ages of patients with DM2 and controls were 63.8 and 64.5 years, respectively. Significant sleep disturbances in patients with DM2 compared to controls included probable RLS (60.0% vs 14.0%, p < 0.0001), EDS (p < 0.001), sleep quality (p = 0.02), and fatigue (p < 0.0001). EDS and fatigue symptoms were independently associated with DM2 diagnosis (p < 0.01) after controlling for age, sex, RLS, and pain scores. There were no group differences in OSA (p = 0.87) or pRBD (p = 0.12) scores.
  
  
  CONCLUSIONS
  RLS, EDS, and fatigue are frequent sleep disturbances in patients with DM2, while OSA and pRBD symptoms are not. EDS was independently associated with DM2 diagnosis, suggesting possible primary CNS hypersomnia mechanisms. Further studies utilizing objective sleep measures are needed to better characterize sleep comorbidities in DM2.
authors.affiliation: Mayo Center for Sleep Medicine, Department of Neurology, Division of Cardiovascular Diseases, St. Mary's Hospital, Mayo Clinic and Foundation, Rochester, MN, USA.
authors.forename: Erek M
authors.initials: EM
authors.lastname: Lam
authors.forename: Paul W
authors.initials: PW
authors.lastname: Shepard
authors.forename: Erik K
authors.initials: EK
authors.lastname: St Louis
authors.forename: Lucas G
authors.initials: LG
authors.lastname: Dueffert
authors.forename: Nancy
authors.initials: N
authors.lastname: Slocumb
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: McCarter
authors.forename: Michael H
authors.initials: MH
authors.lastname: Silber
authors.forename: Bradley F
authors.initials: BF
authors.lastname: Boeve
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Olson
authors.forename: Virend K
authors.initials: VK
authors.lastname: Somers
authors.forename: Margherita
authors.initials: M
authors.lastname: Milone
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D006970:Disorders of Excessive Somnolence / Q000150:complications / Q000503:physiopathology*; D005221:Fatigue / Q000150:complications / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020967:Myotonic Disorders / Q000150:complications / Q000503:physiopathology*; D009223:Myotonic Dystrophy; D010146:Pain / Q000150:complications / Q000503:physiopathology; D012148:Restless Legs Syndrome / Q000150:complications / Q000503:physiopathology*; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000503:physiopathology; D012893:Sleep Wake Disorders / Q000150:complications / Q000503:physiopathology*