Correlation of acoustic voice analysis and Voice Handicap Index in patients with postoperative unilateral vocal cord paralysis after thyroid surgery

Abstract

Unilateral vocal cord paralysis is frequently observed in patients who undergo thyroid surgery. This study explored the correlation between acoustic voice analysis (objective measure) and Voice Handicap Index (VHI, a self-assessment tool). One hundred and forty patients who had thyroid surgery with or without postoperative unilateral vocal cord paralysis (PVCP and NPVCP) were included. The patients were evaluated by the VHI and Dysphonia Severity Index (DSI) tools. VHI scores were significantly higher in PVCP patients than in NPVCP patients. Jitter (%) and shimmer (%) were significantly increased, whereas DSI was significantly decreased in PVCP patients. Receiver operating characteristics curve revealed that VHI scores were associated with the diagnosis of PVCP, of which VHI total score yielded an area under the curve (AUC) of 0.81. Among acoustic parameters, DSI was highly associated to PVCP (AUC=0.82, 95%CI=0.75 to 0.89). Moreover, we found a correlation between VHI scores and voice acoustic parameters. Among them, DSI had a moderate correlation with functional and VHI scores, as suggested by an R value of 0.41 and 0.49, respectively. VHI scores and acoustic parameters were associated with the diagnosis of PVCP.

Figure 1. A, Voice Handicap Index (VHI) parameters including emotional score, functional score, physical score, and total score between patients with and without postoperative unilateral vocal cord paralysis (PVCP and NPVCP). The data are reported as box plots (median and interquartile range) with all the data points. ***P<0.001 from Mann-Whitney test. B, Receiver operating characteristics (ROC) curve analysis showing the diagnostic values of the parameters for PVCP.

Figure 2. A, Voice acoustic analysis compared the parameters including jitter (%), shimmer (%), and Dysphonia Severity Index (DSI) between patients with and without postoperative unilateral vocal cord paralysis (PVCP and NPVCP). The data are shown as box plots with all the data points. ***P<0.001 Mann Whitney test. B, Receiver operating characteristics (ROC) curve analysis was performed to determine the diagnostic values of parameters including jitter (%), shimmer (%), and DSI among patients who underwent thyroid surgery.

Figure 3. A, Spearman correlation analysis displayed the correlation of jitter (%) to Voice Handicap Index (VHI) parameters including emotional score, functional score, physical score, and total score in patients with postoperative unilateral vocal cord paralysis after thyroid surgery. B, Spearman correlation analysis displayed the correlation of shimmer (%) to VHI parameters including emotional score, functional score, physical score, and total score in patients with postoperative unilateral vocal cord paralysis after thyroid surgery. C, Spearman correlation analysis displayed the correlation of Dysphonia Severity Index (DSI) to VHI parameters including emotional score, functional score, physical score, and VHI total score in patients with postoperative unilateral vocal cord paralysis after thyroid surgery.