title: Diagnostic Accuracy of Single Fiber Electromyography for Myasthenia Gravis in Patients Followed Longitudinally.
abstract: BACKGROUND
  The literature lacks data on accuracy of single fiber electromyography (SFEMG) for myasthenia gravis (MG) patients followed longitudinally.
  
  
  METHODS
  We included patients with a clinical suspicion of MG who received SFEMG and follow-up at our institution between 2003 and 2013. Data collected included demographics, symptom details, clinical deficits, other diagnostic testing results, MG medication regimen, duration on treatment, response to therapy, and ultimate diagnosis after follow-up. When available, information was also extracted from the MG-specific Activities of Daily Living, MG Quality of Life, and European Quality of Life assessments before and after SFEMG.
  
  
  RESULTS
  Three hundred forty eight SFEMG patients met inclusion criteria. Myasthenia gravis was ultimately diagnosed in 31% (19% ocular, 12% generalized). A sensitivity of 78% was seen for MG regardless of subtype, 73% for ocular MG, and 85% for generalized MG. A specificity of 91% was obtained for MG of either ocular or generalized subtype.
  
  
  CONCLUSIONS
  The diagnostic accuracy of SFEMG using this methodology minimizing incorporation bias is more reliable than that usually described in previous studies. There is utility in increasing diagnostic yield when SFEMG results are combined with clinical data and those from other diagnostic tests, particularly serology.
authors.affiliation: *Neuromuscular Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio, U.S.A.; and †Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH.
authors.forename: John A
authors.initials: JA
authors.lastname: Morren
authors.forename: Kerry H
authors.initials: KH
authors.lastname: Levin
authors.forename: Robert W
authors.initials: RW
authors.lastname: Shields
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000906:Antibodies / Q000097:blood; D004576:Electromyography; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D009157:Myasthenia Gravis / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology* / Q000523:psychology; D011788:Quality of Life; D012372:ROC Curve; D011950:Receptors, Cholinergic / Q000276:immunology; D012189:Retrospective Studies
chemical_list: D000906:Antibodies; D011950:Receptors, Cholinergic