title: Determining jitter values in the very young by use of the e-norms methodology.
abstract: The diagnosis of myasthenia gravis in very young infants is a challenging one. In young infants, stimulated single-fiber electromyography (StimSFEMG) is the most appropriate technique, but it has serious limitations due to the absence of reference values in this subpopulation. Here we present our efforts to derive a reference range of jitter in a patient cohort of infants <3 years of age using the extrapolated norms, or e-norms, technique.
  
  
  
  The e-norms method was used to calculate jitter mean consecutive difference (MCD) descriptive statistics for children <3 years of age.
  
  
  
  The e-norms derived jitter upper MCD limit was 45 μs in children <1 year, 33 μs in those <2 years, and 26 in those <3 years of age.
  
  
  
  In the absence of jitter reference values for the very young, the e-norms method can be used as an alternative to derive these values from laboratory cohorts. Muscle Nerve 55: 51-54, 2017.
authors.affiliation: Department of Clinical Neurophysiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Pitt
authors.affiliation: Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.
authors.forename: Joe F
authors.initials: JF
authors.lastname: Jabre
mesh_terms: D000367:Age Factors; D002675:Child, Preschool; D015331:Cohort Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D009157:Myasthenia Gravis / Q000175:diagnosis*; D012016:Reference Values
keywords: e-norms; jitter; neuromuscular transmission; pediatric; single-fiber EMG