2022 Workshop Handout Bundle-EMG Laryngeal

EMG Laryngeal - Munin

Pdf Summary

This document discusses the utility of laryngeal electromyography (LEMG) in evaluating vocal fold immobility. Laryngoscopy is commonly used to identify immobility, but it does not provide information about the electrophysiologic status of the larynx. The document highlights that there is no neurologic diagnosis or prognosis for spontaneous recovery based on laryngoscopy alone.<br /><br />The document then discusses the innervation of the larynx, including the superior laryngeal nerve (SLN) and the recurrent laryngeal nerve (RLN). Lesions in these nerves can cause difficulty with high tones, poor vocal quality, and sensory loss in the larynx.<br /><br />It mentions various causes of vocal fold weakness, including post-viral syndrome, surgical trauma, endotracheal tube trauma, tumors, direct laryngeal trauma, and neuromuscular diseases.<br /><br />The document provides localization rules for LEMG lesions, distinguishing between lesions in the RLN and SLN based on abnormality in the thyroarytenoid muscle and cricothyroid muscle. Techniques for LEMG are also discussed, including needle insertion and activation methods.<br /><br />The limitations of LEMG are mentioned, such as its inability to demonstrate conduction block or differentiate focal lesions from systemic diseases without additional testing. The document also explains what information can be learned through LEMG, such as the presence of axon discontinuity (denervation) and decreased motor unit recruitment.<br /><br />The document discusses the concept of electrical synkinesis and its impact on LEMG interpretation. It also mentions that active motor unit potentials and polyphasic potentials within 6 months from injury are predictive of recovery, while fibrillations and positive sharp waves are not predictive. The consensus statement on LEMG for the diagnosis and treatment of vocal cord paralysis is referenced.<br /><br />Finally, the document concludes with an invitation for questions.

Keywords

laryngeal electromyography

vocal fold immobility

laryngoscopy

neurologic diagnosis

recurrent laryngeal nerve

vocal fold weakness

LEMG techniques

axon discontinuity

motor unit recruitment

vocal cord paralysis