[The importance of larynx electromyography for the differential diagnosis of vocal cord fixation]. / Importancia de la electromiografía laríngea para el diagnóstico diferencial de la fijación de las cuerdas vocales.

Fourteen patients have been studied, with precedents of endotracheal intubation, suffering dysphonia and fixation of one vocal cord (13 cases) or both (1 case). The lack of neutrogen signs was confirmed through conventional electromyography, and objectivity because the clinical findings pointing to a direct traumatism of the vocal cord, the cricoarytenoid joint or an inflammatory origin of the damage. We support the limitation of electromyographic procedures of the larynx facing the conductive techniques and concede the possibility of the use of magnetic stimulation with this purpose.

[Electromyographic study of psychogenic dysphonias]. / Estudio electromiográfico de las disfonías psicógenas.

Psychogenic dysphonia traditionally has been considered a case of dystonia in which the functional disturbance is attributed to a disturbance in the synchronization of the laryngeal abductor and adductor muscles. Five patients with psychogenic dysphonia were studied by telelaryngoscopy and conventional laryngeal electromyography. This excluded the neuromuscular origin of the damage and confirmed the diagnosis. A complete glottic gap was present during phonation at the beginning of the exploration, but at the end of the examination, direct laryngoscopy revealed complete glottic closure with normal phonation. Laryngeal electromyography showed no abnormalities suggestive of a neuromuscular origin. In every case, the effort patterns of motor unit potentials were normal and denervation activity was absent in resting conditions.

[Standard electromyography for the diagnosis and prognosis of laryngeal neuromuscular disorders]. / Electromiografía convencional en el diagnóstico y pronóstico de los trastornos neuromusculares de la laringe.

The clinical use of the laryngeal electromyography is still scanty; nevertheless, in our experience it has been shown to be an efficient and objective test in the study of the neurological disorders of the larynx and in the prognosis of recovery after vocal cord paralysis. We have performed conventional electromyography of the thyroarytenoid and cricothyroid muscles in 25 patients with laryngoscopically--confirmed vocal cord paralysis of different etiology. Positive sharp waves, fibrillation potentials and decreased or absent activity on maximal voluntary effort provided enough evidence of denervation in those cases of neurogenic origin. An increased number of polyphasic potentials and increased length of the motor unit potentials recruited in reduced interference patterns were considered suggestive of reinervation, which has an outstanding prognostic value on laryngeal neuropathy. Voluntary motor units, even in some clinically non-mobile vocal cords, were identified in recruitment patterns. Laryngeal electromyography can be done as an office procedure with a minimum of discomfort. It gives objective evaluation of the neuromuscular status, and shows direct evidence of cord function, being useful to distinguish from supranuclear and mechanical disorders of the larynx. It has also shown to be efficient as recovery predictor after vocal cord paralysis.