title: Electrophysiological testing is correlated with myasthenia gravis severity.
abstract: Electrophysiological studies play an important role in the diagnosis of myasthenia gravis (MG). The objectives of this study was to explore the correlation of jitter and decrement with various clinical symptoms and signs and disease severity.
  
  
  
  We performed a retrospective chart review of 75 MG patients who attended the neuromuscular clinic from April 2013 to May 2014. We compared clinical characteristics between patients with high jitter (>100 µs) and decrement (>10%), and patients with lower values to explore the correlations and optimal thresholds of jitter and decrement for different clinical features.
  
  
  
  High jitter and decrement values were associated with more severe disease, manifested by more frequent symptomatic bulbar and limb muscle weakness, more frequent ocular and limb muscle weakness on examination, higher quantitative MG score, and generalized disease.
  
  
  
  The yield of the electrophysiological assessment in MG extends beyond disease diagnosis and correlates with disease severity and the presence of generalized disease. Muscle Nerve 56: 445-448, 2017.
authors.affiliation: Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Division of Neurology, Department of Medicine, University Health Network, University of Toronto, Toronto General Hospital, 200 Elizabeth Street, Room 5 EB 309, Toronto, Ontario, Canada, M5G 2C4.
authors.forename: Alon
authors.identifier: 0000-0002-9020-2399
authors.initials: A
authors.lastname: Abraham
authors.affiliation: Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Division of Neurology, Department of Medicine, University Health Network, University of Toronto, Toronto General Hospital, 200 Elizabeth Street, Room 5 EB 309, Toronto, Ontario, Canada, M5G 2C4.
authors.forename: Ari
authors.initials: A
authors.lastname: Breiner
authors.affiliation: Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Division of Neurology, Department of Medicine, University Health Network, University of Toronto, Toronto General Hospital, 200 Elizabeth Street, Room 5 EB 309, Toronto, Ontario, Canada, M5G 2C4.
authors.forename: Carolina
authors.initials: C
authors.lastname: Barnett
authors.affiliation: Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Division of Neurology, Department of Medicine, University Health Network, University of Toronto, Toronto General Hospital, 200 Elizabeth Street, Room 5 EB 309, Toronto, Ontario, Canada, M5G 2C4.
authors.forename: Hans D
authors.initials: HD
authors.lastname: Katzberg
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, Mount Sinai, Hospital and Lunenfeld Tanenbaum Research Institute, University of Toronto, Toronto, Canada.
authors.forename: Leif E
authors.initials: LE
authors.lastname: Lovblom
authors.affiliation: Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Division of Neurology, Department of Medicine, University Health Network, University of Toronto, Toronto General Hospital, 200 Elizabeth Street, Room 5 EB 309, Toronto, Ontario, Canada, M5G 2C4.
authors.forename: Mylan Ngo
authors.initials: MN
authors.lastname: Rt
authors.affiliation: Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Division of Neurology, Department of Medicine, University Health Network, University of Toronto, Toronto General Hospital, 200 Elizabeth Street, Room 5 EB 309, Toronto, Ontario, Canada, M5G 2C4.
authors.forename: Vera
authors.initials: V
authors.lastname: Bril
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004576:Electromyography / Q000379:methods*; D055724:Electrophysiological Phenomena / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000175:diagnosis* / Q000503:physiopathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index
keywords: QMGS; disease severity; myasthenia gravis; optimal thresholds; repetitive nerve stimulation; single fiber EMG