title: Abnormal spontaneous activity in primary myopathic disorders.
abstract: Reproducible non-insertional spontaneous activity (SA), with the exception of endplate activity, is an unequivocal sign of abnormality and is one of the most useful findings obtained on electromyography.
  
  
  
  In this retrospective study we analyzed occurrence and distribution of abnormal SA in 151 patients with genetically confirmed myopathies.
  
  
  
  Complex repetitive discharges (CRDs) occurred more frequently than fibrillation potentials (fibs) and positive sharp waves (PSWs) in centronuclear myopathy (CNM) and limb-girdle muscular dystrophy type 2A (LGMD-2A), whereas fibs/PSWs were observed more often in desminopathy and facioscapulohumeral dystrophy (FSHD). Abnormal SA was commonly found in CNM (66.7%) and desminopathy (61.5%), occasionally in Duchenne (DMD) and Becker muscular dystrophy (BMD) (45.2% and 27.6%, respectively), but rarely in FSHD (14.9%) and LGMD-2A (12.0%).
  
  
  
  Abnormal SA probably occurs more frequently in disorders associated with structural changes in muscle fibers. Screening for SA may be a valuable tool for diagnosis of non-myotonic myopathies. Muscle Nerve 56: 427-432, 2017.
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Nojszewska
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Gawel
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Szmidt-Salkowska
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Kostera-Pruszczyk
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Potulska-Chromik
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Lusakowska
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Biruta
authors.initials: B
authors.lastname: Kierdaszuk
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Lipowska
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Macias
authors.affiliation: Department of Biochemistry and Molecular Biology, Centre of Postgraduate Medical Education, Marymoncka Strasse 99/103, 01-813, Warsaw, Poland.
authors.forename: Damian
authors.initials: D
authors.lastname: Gawel
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Seroka
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Kaminska
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004576:Electromyography / Q000379:methods; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009135:Muscular Diseases / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology*; D012189:Retrospective Studies; D055815:Young Adult
keywords: CRD; PSW; electromyography; fibrillation potentials; hereditary muscle diseases