From Larynx to Vocal Ability: New Electro-Physiological Data

Abstract

The objectives of phoniatric diagnostics and therapy are the small muscles of the voice- and speech-producing organs. Electrodiagnostics of functional and neuromuscular disorders in this field are difficult, because of the hidden anatomical situation. On the other hand electrodiagnostics enable an objective diagnosis and documentation. The method offers the possibility of electromyography of the larynx, palate and tongue during voluntary muscle contraction and neuromyography after electrostimulation of the afferent nerve, especially the X cranial nerve and reflex myography after electrostimulation of the contralateral nerve. The theory on which the method is based is described for both healthy and diseased neuromuscular units. The convenience of application of the electrodes during zoom endoscopy under surface anesthesia in the alert patient is shown, with special emphasis on 80 micron copper wire electrodes, especially in disorders of coordination. Apart from being well tolerated by the patients, the method enables a clear differentiation of organic lesions, i.e. into degenerative and non-degenerative paralysis. In addition to this, electromyogram reflex measurements can verify psychogenic aphonia or other functional dysfunctions. Myopathies and neurological diseases that cause voice and speech disorders can be diagnosed using electrodiagnostics. At present the main field for this method undoubtedly is the differential diagnosis of palsies; but due to its objective measurement and quantitation of disorders of coordination it should also be used in the diagnosis of speech and voice disorders of different etiologies. Computerized electromyography analysis and electro-stimulation with train should enable an even more detailed analysis in the future.