title: Major involvement of trunk muscles in myotonic dystrophy type 1.
abstract: OBJECTIVE
  The motor impairments in Myotonic Dystrophy 1 (DM1) are assumed to progress from distal toward proximal parts of the extremities in the Juvenile and Adult forms of DM1. On occasion and late in progress spine deformity is observed. In this study we have examined whether and to what extent trunk muscles are impaired in DM1, and if this impairment is correlated with the duration of the disorder, walking capacity, mobility, balance, and CTG-repeats.
  
  
  METHODS
  Manual muscle testing (MMT) of skeletal muscle strength in trunk and extremities, reassessment of the mutation size, time since first symptom, the 6 min walk test (6MWT), Rivermead mobility index (RIM) and Timed up & go (TUG) were sampled in 38 adult DM1 outpatients.
  
  
  RESULTS
  We found significant impairment in trunk muscles. Trunk muscle strength decreased significantly with increasing mutation size (r = -0.64, P < 0.001). Reduced walking capacity, mobility and balance were significantly related to decreased trunk muscle strength.
  
  
  CONCLUSIONS
  DM1 affects trunk muscle groups. The trunk impairments seem to occur relatively early in disease progression. Awareness of trunk impairments may be of importance for everyday functioning and for understanding the risk of injuries due to falls reported among DM1 patients. It may also help in identification of DM1 patients and considered outcome measure in future clinical trials.
authors.affiliation: Department of Neurology, Drammen Hospital, Vestre Viken Health Trust, Drammen, Norway. grosolba@gmail.com, gro.solbakken@vestreviken.no.|Department of Neurology, Oslo University Hospital, Oslo, Norway. grosolba@gmail.com, gro.solbakken@vestreviken.no.
authors.forename: G
authors.initials: G
authors.lastname: Solbakken
authors.affiliation: Department of Neurology, Oslo University Hospital, Oslo, Norway.
authors.forename: K
authors.initials: K
authors.lastname: Ørstavik
authors.affiliation: Department of Neurology, Drammen Hospital, Vestre Viken Health Trust, Drammen, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Hagen
authors.affiliation: Department of Neurology, Oslo University Hospital, Oslo, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: E
authors.initials: E
authors.lastname: Dietrichs
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|NevSom - Department of Rare Disorders and Disabilities, Oslo University Hospital, Oslo, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Naerland
mesh_terms: D000328:Adult; D017668:Age of Onset; D042622:DNA Repeat Expansion; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009154:Mutation / Q000235:genetics; D009223:Myotonic Dystrophy / Q000235:genetics / Q000503:physiopathology*; D009460:Neurologic Examination; D004856:Postural Balance; D013909:Thorax / Q000503:physiopathology; D016138:Walking; D055815:Young Adult
keywords: balance; mobility; muscle strength; myotonic dystrophy; myotonic dystrophy protein kinase; trunk