[The value of acoustic parameters in the voice therapy for patients with unilateral vocal cord paralysis]

Objective: To investigate the value of acoustic parameters in the voice therapy for patients with unilateral vocal cord paralysis (UVCP). Methods: From May 2015 to April 2018, 51 patients with UVCP and 59 healthy controls in Department of Otorhinolaryngology Head and Neck Surgery, Tianjin First Central Hospital, were involved in this research retrospectively. The UVCP patients were diagnosed with stroboscopic laryngoscopy. The minimum glottal area (MGA) was calculated by KIPS software when the people were pronouncing/i:/. The fundamental frequency (F0), Jitter, Shimmer and NHR were detected by CSL4500 multiple acoustic voice analyzer. Results: MGA of UVCP patients was much higher than that of healthy control (male: 433.68±64.52 vs. 294.41±51.82, t=9.23, P=0.000; female: 498.80±73.42 vs. 302.03±76.54, t=13.21, P=0.000), which meaned vocal cord insufficiency.After voice therapy, MGA reduced significantly (male: 288.48±55.09, female: 258.22±57.17, t=24.41 and 31.22, P=0.000 vs. pre-therapy). MGA of untreated patients decreased in varying degrees. Compared with the voice therapy group, the MGA decreased in a significantly lower extent (24.25±22.91 vs. 188.31±54.37, t=8.97, P=0.000). The F0, Jitter, Shimmer and NHR raised significantly in UVCP patients group (P=0.000 vs. healthy control group), and they were reduced by voice therapy (all P<0.05). Each of the four acoustic parameters was relative with MGA, r=0.551, 0.867, 0.853 and 0.875 in turn, P=0.001, 0.000, 0.000, and 0.000. Conclusion: MGA and acoustic parameters can reflect the acoustic features of UVCP patients, which are useful tools in the UVCP assessment and voice therapy.