The clinical value of laryngeal electromyography in laryngeal immobility.

Although laryngeal electromyography (LEMG) is commonly performed, there are no data confirming its efficacy. We evaluated 40 patients with a laryngoscopic diagnosis of unilateral vocal-fold immobility who underwent LEMG of the thyroarytenoid (TA) and cricothyroid (CT) muscle, with the immobile side of each muscle being compared to the normal side. The immobile side compared to the normal side showed more fibrillation potentials and positive sharp waves for the TA (p=0.04), longer MUAP duration for the TA (p=0.04) and CT (p=0.01), more polyphasic potentials for the TA (p=0.002), and more frequent decreased recruitment for the TA (p<0.01) and CT (p=0.008). Specificity and positive predictive value were around 90%. Sensitivity, negative predictive value and accuracy were around 50%. These results suggest that altered LEMG findings are reliable and they can be used to determine the innervation status of an immobile muscle. Conversely, when the LEMG is normal, the results should be reviewed.