Prognostic Indicators of Unilateral Vocal Fold Paralysis

Objectives: 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. Design: Cohort study with retrospective data analysis. Setting: Voice clinic of a tertiary medical center. Patients: 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. Main Outcome Measure: 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. Conclusion: 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.