2026 Workshop Handout Bundle-W08A - EMG Laryngeal Handout

W08A - EMG Laryngeal Handout - Munin

Pdf Summary

This review describes how laryngeal electromyography (LEMG) can diagnose recurrent laryngeal nerve (RLN), superior laryngeal nerve (SLN), and vagal injuries and guide prognosis and treatment for vocal fold (VF) dysfunction. Such injuries—often related to surgery in the neck or chest—can impair voice, swallowing, and breathing. Laryngoscopy identifies abnormal VF movement, while LEMG helps distinguish neuropathy from mechanical fixation and localize nerve involvement.<br /><br />LEMG assesses laryngeal muscle activity at rest and during tasks such as voicing, sniffing, and pitch elevation. Interpretation combines qualitative findings, including spontaneous activity and motor-unit recruitment, with quantitative analysis. In the thyroarytenoid–lateral cricoarytenoid (TA-LCA) muscles, approximately 400 turns per second is a reference for normal recruitment; lower values support neuropathy. Testing for electrical synkinesis is also important: after nerve injury, misdirected reinnervation can cause adductor muscles to activate inappropriately during sniffing. Synkinesis worsens the expected likelihood of VF motion recovery and cannot reliably be identified by laryngoscopy alone.<br /><br />LEMG is most useful when performed at appropriate intervals after injury. Serial testing can track denervation and reinnervation; findings obtained around or after two months may be especially informative for identifying a poor prognosis. Combining recruitment, spontaneous activity, motor-unit characteristics, quantitative turns, synkinesis, and timing improves prognostic accuracy.<br /><br />The resulting prognosis supports individualized care, including observation, temporary VF injection or augmentation, permanent medialization, or laryngeal reinnervation. LEMG can also help guide management of bilateral paralysis and clarify unexpected treatment failure. The authors recommend a coordinated approach involving an electromyographer and laryngologist. While LEMG has technical limitations and no established RLN or SLN conduction study is available, it can provide clinically valuable information beyond examination alone and help avoid unnecessary delays in treatment.

Keywords

laryngeal electromyography

recurrent laryngeal nerve

superior laryngeal nerve

vagal injury

vocal fold dysfunction

laryngoscopy

synkinesis

nerve prognosis

laryngeal reinnervation

vocal fold paralysis