title: Reference values for jitter recorded by concentric needle electrodes in healthy controls: A multicenter study.
abstract: BACKGROUND
  The aim of this study was to create reference values for jitter measured with concentric needle electrodes.
  
  
  METHODS
  Operators worldwide contributed recordings from orbicularis oculi (OO), frontalis (FR), and extensor digitorum (ED) muscles in healthy controls. Criteria for acceptable signal quality were agreed upon in advance. Fifteen or 20 recordings of acceptable quality from each muscle were required for voluntary and electrical stimulation recordings, respectively.
  
  
  RESULTS
  Recordings from 59 to 92 subjects were obtained for each muscle and activation type. Outlier limits for mean consecutive difference and individual jitter data for voluntary activation were: OO, 31 and 45 µs; FR, 28 and 38 µs; ED, 30 and 43 µs; and for electrical stimulation they were: OO, 27 and 36 µs; FR, 21 and 28 µs; ED, 24 and 35 µs.
  
  
  CONCLUSIONS
  Reference jitter values from concentric needle electrode recordings were developed from signals of defined quality while seeking to avoid creating supernormal values.
authors.affiliation: Department of Neuroscience, Clinical Neurophysiology, Uppsala University, Uppsala, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Stålberg
authors.affiliation: Department of Neurology, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Donald B
authors.initials: DB
authors.lastname: Sanders
authors.affiliation: Department of Clinical Neurophysiology, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
authors.forename: Sajjad
authors.initials: S
authors.lastname: Ali
authors.affiliation: Clinical Neurophysiology, Karolinska University Hospital, Stockholm, Sweden.|The Wellcome Trust for Neuroimaging, University College of London, London, UK.
authors.forename: Gerald
authors.initials: G
authors.lastname: Cooray
authors.affiliation: Institute of Clinical Neurophysiology, University Medical Center Ljubljana, Ljubljana, Slovenia.
authors.forename: Lea
authors.initials: L
authors.lastname: Leonardis
authors.affiliation: Department of Clinical Medicine, The Artic University of Norway, Tromsø, Norway.|Department of Clinical Neurophysiology, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Sissel
authors.initials: S
authors.lastname: Löseth
authors.affiliation: Department of Neurology and Neurosurgery, Medical School, Universidade de São Paulo, São Paulo, Brazil.|Fleury Medicina e Saúde, São Paulo, Brazil.
authors.forename: Flavia
authors.initials: F
authors.lastname: Machado
authors.affiliation: San Rafael University Hospital, Granada, Spain.|Department of Clinical Neurophysiology, Ibermutuamur, Granada, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Maldonado
authors.affiliation: Department of Clinical Neurophysiology, Vithas Virgen del Mar Hospital, Almeria, Spain.|Doctoral Program in Clinical Medicine and Public Health, University of Granada, Granada, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Martinez-Aparicio
authors.affiliation: Department of Neuroscience, Clinical Neurophysiology, Uppsala University, Uppsala, Sweden.
authors.forename: Arne
authors.initials: A
authors.lastname: Sandberg
authors.affiliation: Department of Neurology, Mayo Clinic College of Medicine, Scottsdale Arizona, USA.
authors.forename: Benn
authors.initials: B
authors.lastname: Smith
authors.affiliation: Department of Neuroscience, Clinical Neurophysiology, Uppsala University, Uppsala, Sweden.|Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Widenfalk
authors.affiliation: Neuromuscular Investigation Laboratory, Faculdade Medicina São José do Rio Preto, São Paulo, Brazil.
authors.forename: João
authors.initials: J
authors.lastname: Aris Kouyoumdjian
mesh_terms: D000328:Adult; D001703:Biophysics; D004558:Electric Stimulation; D004566:Electrodes; D004576:Electromyography; D005071:Evoked Potentials / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D009469:Neuromuscular Junction / Q000502:physiology*; D012016:Reference Values; D013223:Statistics as Topic
keywords: SFEMG; concentric needle electrode; healthy controls; jitter; reference material