Electromyography of the larynx and related technics.

Electrodiagnosis of the laryngeal muscles by electromyography, neuromyography and reflexmyography enables diagnosis, follow up and prognosis of vocal cord palsies as well as indications for surgery. The development of new endoscopes now permits direct inspection of the oropharyngeal and endolaryngeal muscles. A method of transoral electromyography of laryngeal muscles in the awake patient has been established using these zoom-endoscopes for supervision of the transoral placement of needle or hooked-wire electrodes into the muscular agonists and antagonists of the larynx. Both spontaneous and voluntary activity may be recorded since the patient can follow instructions. Combined with this endoscopic electromyography of the larynx neuromyography by electrostimulation of the laryngeal nerves with surface electrodes considerably enhances diagnosis and prognosis of recurrent nerve lesions. Furthermore, the reflex arc of the upper and lower laryngeal nerves can be tested with electric stimulation and measurement of the response activity during reflex glottic closure. Classification of degenerative and nondegenerative palsies is enabled by these procedures. In addition, these neurophysiological methods are useful for diagnosis of functional larynx disorders of other origin.