KAREN H.CALHOUNMDRONALD B.KUPPERSMITHMD
IN MY INSTITUTION, our experience with LEMG has been primarily in the assessment of the conditions of patients with immobile vocal folds and in the diagnosis and treatment of movement disorders affecting the larynx. Our techniques vary from those reported in that we most commonly use a monopolar electrode, which records a larger sample of the muscle activity. While we have found bipolar electrodes useful in quantitative measurements of muscle activation, we do not find them particularly helpful in clinical practice. In our hands, the bipolar techniques are more sensitive to placement and movement, and amplitude values are limited due to the small test area between the electrodes. Although LEMG is a nice adjunctive assessment tool, it is limited in that there are subjective elements in technique and in the interpretation of degree of recruitment and inappropriate muscle activity. In the evaluation of immobile vocal folds, we find a spectrum of responses ranging from denervation with fibrillation potentials, to reinnervation with polyphasic potentials and prolonged motor unit potentials, to frequently normal motor unit potentials in the absence of scarring or obvious mechanical fixation at the other end of the spectrum.
Ford CN. Laryngeal EMG in Clinical Neurolaryngology. Arch Otolaryngol Head Neck Surg. 1998;124(4):476-477. doi:10.1001/archotol.124.4.476