Laryngeal electromyography and prognosis of unilateral vocal fold paralysis--a long-term prospective study

Abstract

Objectives/hypothesis: To confirm the value of using laryngeal electromyography (LEMG) to predict the long-term prognosis of unilateral vocal fold paralysis (UVFP), and elucidate the adequate timing of LEMG.

Study design: Prospective cohort prognosis study.

Methods: The LEMG data of 84 patients with UVFP were prospectively collected, and 81 patients received follow-up at least 6 months after symptom onset. If the paralyzed vocal fold had <20% recruitment reduction during phonation compared to the normal vocal fold signals, and absence of fibrillation when the patient was silent, the prognosis was considered to be good (negative finding). Otherwise, the prognosis was considered to be poor (positive finding). The association between UVFP outcome and LEMG prognostic rules and the accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of LEMG were calculated.

Results: The mean duration of LEMG after symptom onset was 3.7 months, and follow-up after symptoms onset was 18.4 months. Sixty-six of 71 patients with a positive finding had persistent UVFP; four of 10 patients with a negative finding recovered vocal fold motion. LEMG results were significantly associated with the outcome of UVFP (P = .007). The overall accuracy, sensitivity, specificity, PPV, and NPV of LEMG were 86.4%, 91.7%, 44.4%, 93.0%, and 40.0%, respectively. When LEMG was done more than 2 months after symptom onset, the PPV was 97.9%.

Conclusions: LEMG has a high PPV in predicting the long-term outcome of UVFP patients with poor prognosis. Permanent laryngeal framework surgery is feasible if patients have positive findings at least 2 months after symptom onset.

Keywords: Fibrillation; laryngeal electromyography; prognosis; recruitment reduction; vocal fold paralysis.