Laryngeal deglutition movement in Parkinson's disease.

Laryngeal muscle function is defective in Parkinson's disease (PD) patients; the intrinsic group (vocal cords) is defective during phonation and the extrinsic group (laryngeal strap muscles) is slow during deglutition. There are no studies of vocal cord motility during deglutition in PD. We investigated laryngeal motility during deglutition in 71 patients with PD in a videofluoroscopic swallowing study. Patients were subdivided into two groups by the Hoehn and Yahr disability scale, stages II and III (n = 38) and stages IV and V (n = 33). At least one abnormality of laryngeal movement was present in 68 of 71 patients (95.8%); most patients had multiple abnormalities. There was statistically significant slowing of vertical laryngeal excursion; true vocal cord closure; or delayed, incomplete, or absent opening of the true vocal cords. Patients with more advanced disease manifested more deficits of laryngeal movement. Laryngeal dysmotility in PD may be related to defective descending basal ganglionic control of medullary deglutory and phonatory motor functions.