title: Decomposition-based quantitative electromyography in the evaluation of muscular dystrophy severity.
abstract: BACKGROUND
  Electromyography is useful in the diagnosis of myopathies, but its utility in determining disease severity requires further investigation. In this study we aimed to determine whether decomposition-based quantitative electromyography (DQEMG) could indicate the severity of involvement in a cohort of patients with muscular dystrophies (MDs).
  
  
  METHODS
  Fifteen patients with facioscapulohumeral (FSHD), limb-girdle (LGMD), and Becker (BMD) muscular dystrophy, and 7 healthy controls, participated in this investigation. Knee extensor isometric strength differentiated the "more severe" and "less severe" MD groups. The vastus lateralis (VL), biceps brachii (BB), and tibialis anterior (TA) muscle groups were investigated using DQEMG.
  
  
  RESULTS
  All muscles from the MD group showed changes in mean MUP (motor unit potential) AAR (area-to-amplitude ratio), and turns, compared with controls (P < 0.05). More severely affected muscles (VL and BB) also had shortened mean MUP durations compared with controls (P < 0.01).
  
  
  CONCLUSIONS
  DQEMG was capable of indicating the severity of MD involvement, as changes in MUP morphology reflected the progressive nature of the disease.
authors.affiliation: School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 339 Windermere Road, London, Ontario N6A 5A5, Canada.
authors.forename: Kendra L
authors.initials: KL
authors.lastname: Derry
authors.forename: Shannon L
authors.initials: SL
authors.lastname: Venance
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Doherty
mesh_terms: D000328:Adult; D015331:Cohort Studies; D003627:Data Interpretation, Statistical; D018450:Disease Progression; D004576:Electromyography / Q000379:methods*; D055724:Electrophysiological Phenomena; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology; D009136:Muscular Dystrophies / Q000175:diagnosis* / Q000503:physiopathology*; D049288:Muscular Dystrophies, Limb-Girdle / Q000175:diagnosis / Q000503:physiopathology; D020388:Muscular Dystrophy, Duchenne / Q000175:diagnosis / Q000503:physiopathology; D020391:Muscular Dystrophy, Facioscapulohumeral / Q000175:diagnosis / Q000503:physiopathology; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult