Unilateral Vocal Fold Paralysis Workup

Updated: Jan 26, 2021
  • Author: Thomas L Carroll, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Imaging Studies

Although rarely obtained today for the workup of unilateral vocal fold paralysis (UVFP), chest radiography is sometimes the first screening evaluation for a patient with UVFP of unknown etiology, ordered by a physician for other comorbid chest symptoms. This may reveal a chest malignancy as the cause of the UVFP. A Pancoast tumor, mediastinal mass, or even massive cardiomegaly may be found. The latter has rarely been shown to be a cause of UVFP when enlargement of the left atrium that causes a stretch injury to the left recurrent laryngeal nerve is present (Ortner syndrome).

CT scanning or MRI of the path of the vagus/recurrent laryngeal nerve should be performed as part of a workup for a UVFP of unknown etiology. The imaging should include the entire path of the vagus/recurrent laryngeal nerve involved. A left UVFP involves imaging from the base of skull to the mid chest (through the arch of the aorta). The right UVFP evaluation should extend from the base of the skull through the clavicle. Although CT is usually the test of choice, the decision between CT scanning and MRI is personal and can be decided by the otolaryngologist and radiologist.


Other Tests

Voice evaluation

Voice evaluation by a speech-language pathologist is often helpful to determine the degree of maladaptive compensatory behavior present. In addition, voice recording provides documentation of the baseline voice quality and ability. This is important because treatment for the vocal fold paralysis usually begins shortly after evaluation. Often, this voice evaluation includes an objective analysis of the voice quality of the patient, including acoustic and aerodynamic analysis (air flow and laryngeal efficiency) of speech production.

Laryngeal electromyography (LEMG)

LEMG is an electrophysiologic evaluation of the muscles of the larynx. This test is performed using an EMG needle percutaneously under local or no anesthesia. The LEMG most often involves an evaluation of the thyroarytenoid/lateral cricoarytenoid muscle complex, which is reflective of the recurrent laryngeal nerve innervation and the cricothyroid muscle, which is indicative of the superior laryngeal nerve status/function.

LEMG findings can be diagnostic and prognostic and can therefore be a useful tool to guide therapy. LEMG can be used to differentiate between vocal fold immobility caused by cricoarytenoid joint pathology and that caused by vocal fold paralysis. The timing of LEMG is crucial in accurately determining the prognosis of spontaneous recovery of the paralyzed vocal fold. LEMG is most predictive of outcome if performed 6 weeks to 6 months after the onset of symptoms. LEMG can shorten the time until permanent treatment is implemented, subsequently reducing the time of the patient's dysphonia and the number of temporary treatments required.