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. 2021 Oct 27;13(21):5379. doi: 10.3390/cancers13215379

Figure 2.

Figure 2

Preoperative and postoperative voice parameters with different severity of recurrent laryngeal nerve dysfunction. In Group A (blue line), B (red line), and C (gray line), post-dissection R2 signals were <50%, 50–90%, and >90% lower than pre-dissection R1 signals, respectively. Fmax = Maximum pitch frequency; Fmin = Minimum pitch frequency; PR = Pitch range; Mean F0 = mean fundamental frequency; NHR = noise-to-harmonic ratio; IVST = Index of Voice and Swallowing Handicap of Thyroidectomy; IVST-T = Total IVST score; IVST-V = IVST score of voice domain score; IVST-S= IVST score of swallowing domain. The units of each voice parameter were as follows: Fmax(Hz), Fmin(Hz), PR(semitone), Jitter(%), Shimmer(%), NHR(value); IVST-T(score); IVST-V(score); IVST-S(score). Period I = Preoperative period (within two months prior to surgery); period II = Immediate postoperative period (median duration of three days; range of one to seven days); period III = Short-term postoperative period (median duration of 12 days; range of seven–30 days); period IV = Long-term postoperative period (median duration of 40 days, range of 30–90 days). Asterisk represents p value < 0.05, showed significant difference.