title: Concentric needle jitter on voluntary activated frontalis in 20 healthy subjects.
abstract: BACKGROUND
  Normative data for jitter parameters using a disposable concentric needle have been described in a few studies.
  
  
  METHODS
  Jitter, expressed as the mean consecutive difference (MCD), was measured in the frontalis muscle in 20 subjects by voluntary contraction.
  
  
  RESULTS
  Mean MCD for individual studies (20, gaussian), all potentials (400, non-gaussian), and 18th highest value (20, gaussian) were 19.9 ± 2.9 μs, 19.9 ± 6.6 μs, and 26.9 ± 4.4 μs, respectively.
  
  
  CONCLUSIONS
  The suggested upper normal limit for mean MCD is 26 μs and for outliers is 36 μs.
authors: Faculdade de Medicina de São José do Rio Preto (FAMERP), Department of Neurological Sciences, Rua Luiz Antônio da Silveira 1661, 15025-020, São José do Rio Preto, São Paulo, Brazil. jaris@terra.com.br
authors: João A
authors: JA
authors: Kouyoumdjian
authors: Erik V
authors: EV
authors: Stålberg
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D004576:Electromyography / Q000295:instrumentation / Q000379:methods; D055724:Electrophysiological Phenomena; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D009339:Needles; D016011:Normal Distribution; D011446:Prospective Studies; D055815:Young Adult