Observations on so-called idiopathic vocal cord paralysis.

A series of 238 patients with laryngeal paralysis seen during a six-year period (1976-1982) were studied with serial 16-mm motion picture filmstrips. There were 39 cases in which no etiological disease process could be found responsible for the paralysis; these were called "idiopathic." In all 39 cases, both the superior and recurrent laryngeal nerves were paralyzed indicating that the lesion involved the central (nuclear) lower motor neurons of the dorsal and ventral nucleus ambiguus. The high incidence of upper respiratory infections suggests a viral etiology in many cases. The ability to separate a pure recurrent from a combined superior and recurrent laryngeal paralysis on morphological indirect endoscopic appearance has significant diagnostic and therapeutic implications.