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.
Cohort study with retrospective data analysis.
Voice clinic of a tertiary medical center.
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.
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.
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.