Elsevier

Journal of Voice

Volume 24, Issue 2, March 2010, Pages 228-234
Journal of Voice

Laryngeal Electromyography: Clinical Application

https://doi.org/10.1016/j.jvoice.2008.08.005Get rights and content

Summary

Laryngeal electromyography (LEMG) is a valuable adjunct in clinical management of patients with voice disorders. LEMG is valuable in differentiating vocal fold paresis/paralysis from cricoarytenoid joint fixation. Our data indicate that visual assessment alone is inadequate to diagnose neuromuscular dysfunction in the larynx and that diagnoses based on vocal dynamics assessment and strobovideolaryngoscopy are wrong in nearly one-third of cases, based on LEMG results. LEMG has also proven valuable in diagnosing neuromuscular dysfunction in some dysphonic patients with no obvious vocal fold movement abnormalities observed during strobovideolaryngoscopy. Review of 751 patients suggests that there is a correlation between the severity of paresis and treatment required to achieve satisfactory outcomes; that is, LEMG allows us to predict whether patients will probably require therapy alone or therapy combined with surgery. Additional evidence-based research should be encouraged to evaluate efficacy further.

Introduction

Laryngeal electromyography (LEMG) is a technique to assess the integrity of laryngeal nerves and muscles. It was introduced in 1944 by Weddel et al1 and developed further by Faaborg-Andersen, Buchtal, and others in the 1950s.2, 3, 4 LEMG has become increasingly important clinically throughout the last decade of the 20th century and first decade of the 21st century, as reviewed by Sataloff et al.5 However, despite extensive use of LEMG, in a 2003 practice parameter report, Sataloff et al6 highlighted the surprising paucity of high-quality, evidence-based research confirming or refuting the clinical value of LEMG. The practice parameter highlighted the need for additional data regarding the clinical value of LEMG. Several papers published recently have added important information to the literature.7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 This report has been prepared to help clarify further the clinical value of LEMG.

Section snippets

Materials and methods

All subjects are patients of the senior author (R.T.S) and his associates. All subjects had undergone dynamic voice assessment and strobovideolaryngoscopy with flexible and rigid endoscopes, using a protocol that has been published previously.25 If laryngeal movement abnormalities or asymmetries were seen, patients were referred for LEMG. LEMG is easy to perform, presents minimal risk to patients, and is a well-tolerated in-office procedure. Our patients are referred to a neurologist (S.M) who

Results

Strobovideolaryngoscopic findings are summarized in Table 2. Patients with a diagnosis of arytenoid dislocation also underwent laryngeal CT as well as arytenoid palpation in nearly all cases. LEMG in these patients was normal or revealed mild paresis insufficient to explain vocal fold immobility. LEMG was helpful in these patients in establishing or confirming the diagnosis of mechanical fixation, as reported previously.26, 27, 28, 29

Table 3 summarizes laryngeal nerve function as assessed by

Discussion

LEMG has become a common adjunct in the care of voice patients. The procedure may be performed by a neurologist, physiatrist, or laryngologist skilled in electrodiagnostic medicine. The most appropriate electrode choice (monopolar, bipolar, concentric, hooked wire, or single fiber) varies depending on the clinical information desired. We use monopolar electrodes routinely to obtain a global assessment of neuromuscular function of individual laryngeal muscles. Under specific circumstances, we

Conclusion

Our experience and the data reported in this study suggest that LEMG provides useful prognostic information regarding the likelihood of recovery of satisfactory phonatory function without surgery, following vocal fold paresis or paralysis. Patients with mild paresis are less likely to require laryngeal surgery than those with severely reduced recruitment response. Laryngeal EMG also provides valuable diagnostic information for differentiating vocal fold paresis or paralysis from mechanical

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