title: Prognostic indicators of unilateral vocal fold paralysis.
abstract: OBJECTIVE
  To determine the possible prognostic indicators of unilateral vocal fold paralysis (UVFP) and survey the timing and values of preset laryngeal electromyography (LEMG) rules for UVFP.
  
  
  METHODS
  Cohort study with retrospective data analysis.
  
  
  METHODS
  Voice clinic of a tertiary medical center.
  
  
  METHODS
  Complete data for 45 patients diagnosed with idiopathic or iatrogenic UVFP. The LEMG was performed between 3 weeks and 6 months from the onset of symptoms.
  
  
  METHODS
  At least 6 months after symptom onset and 3 months after LEMG.
  
  
  RESULTS
  Thirteen subjects showed resolved vocal fold motion (29%), and 32 had persistent vocal fold paralysis (71%). According to the LEMG decision rules proposed by Munin et al in 2003, the predictive values for positive results, negative results, sensitivity, specificity, and accuracy of LEMG were 78.9%, 71.4%, 93.8%, 38.5%, and 77.8%, respectively. We found the false-positive rate to be as high as 50% if LEMG was performed less than 2 months after symptom onset, and only 7.7% if LEMG was performed at least 2 months after symptom onset. After excluding 14 LEMG data recorded at less than 2 months, the predictive values for positive results, negative results, sensitivity, specificity, and accuracy of LEMG were 92.3%, 60%, 92.3%, 60.0%, and 87.1%, respectively. The predictive values of positive results and accuracy significantly improved without compromising sensitivity.
  
  
  CONCLUSIONS
  This study confirms that LEMG is a clinically useful tool that can offer prognostic information for UVFP especially if it is done at least 2 months after symptom onset.
authors.affiliation: School of Medicine, National Defense Medical Center, and Department of Medicine, Chung-Shan Medical University, Taichung, Taiwan. ccwang@vghtc.gov.tw
authors.forename: Chen-Chi
authors.initials: CC
authors.lastname: Wang
authors.forename: Ming-Hong
authors.initials: MH
authors.lastname: Chang
authors.forename: Ching-Ping
authors.initials: CP
authors.lastname: Wang
authors.forename: Shi-An
authors.initials: SA
authors.lastname: Liu
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D020127:Recovery of Function / Q000502:physiology*; D012189:Retrospective Studies; D012737:Sex Factors; D013997:Time Factors; D014826:Vocal Cord Paralysis / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*