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. 2021 Nov 30;12:755231. doi: 10.3389/fendo.2021.755231

Figure 2.

Figure 2

Voice parameter changes (Δ) with different vocal cord movement (VFM) outcomes: R Group (Blue line) and U Group (Red line). 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. period I, Preoperative period (within 2 months before surgery); period II, Immediate postoperative period (median duration of 3 days; range of 1-7 days); period III, Short-term postoperative period (median duration of 12 days; range of7-30 days); period IV, Long-term postoperative period (median duration of 40 days, range of 30-90 days). The equation for calculating postoperative change in objective voice analysis (Fmax, Fmin, PR, Mean F0, Jitter, Shimmer, NHR) data was Δ= (B - A)/A, the unit is %; the equation for calculating postoperative change in subjective voice analysis (IVST-T, IVST-V, IVST-S) data was Δ= B – A, the unit is score. Where A and B are preoperative and postoperative values, respectively. The preoperative Δ is 0 in all the voice parameter. p value <0.05, showed significant difference.