The Role of Laryngeal Electromyography in Vocal Fold Immobility

Abstract

Aim of Study: To assess the utility of laryngeal electromyography (EMG) as a diagnostic method for patients with immobile vocal folds and to evaluate its possible role as a prognostic indicator in the management of those cases. Methodology: The study included 35 patients with unilateral vocal fold immobility (VFI) and 10 normal controls. All patients were subjected to full history taking and thorough clinical examination and radiological investigations. Laryngeal EMG was performed for all the patients and controls. Results: The specificity of EMG was 100%, while the sensitivity was 65.7% in detecting VFI. Seventeen cases (74%) with abnormal EMG data had a combined lesion of recurrent and superior laryngeal nerves and 6 cases (26%) had isolated recurrent laryngeal nerve lesion. In both groups there was no statistical difference as regards the position of the paralyzed vocal fold in either paramedian or lateral positions. Clinical follow-up with indirect laryngoscopy, 6 months later, revealed recovery in 10 of the 25 cases (40%). None of the recovered patients showed abnormal EMG data at presentation, while 13 out of 15 cases of non-recovered patients showed abnormal EMG data, i.e. the specificity of EMG was 100%, while the sensitivity was 86.6% in predicting recovery in patients with VFI. The quantitative analysis of the interference pattern was more sensitive (65.7 and 86.6%) than the conventional methods of analysis (60 and 80%) in detecting and predicting recovery in patients with immobile vocal folds, respectively. Conclusion: The clinical use of laryngeal EMG is an efficient and objective test in the study of patients with immobile vocal folds and in predicting recovery of those cases. It is also a useful tool in the diagnostic algorithm in vocal fold paralysis.