Acoustic parameters for the evaluation of voice quality in patients with voice disorders.

BACKGROUND

To investigate the value of the standard deviation of the fundamental frequency (F0 SD), jitter, and shimmer for the evaluation of voice quality and the description of vocal characteristics in patients with voice disorders.

METHODS

This prospective cohort study included 4 groups: vocal cord polyps (VCP) group (n=55), early-stage (stage I-II) laryngeal carcinoma (ELC) group (n=35), mutational falsetto (MF) group (n=17), and a normal control group (n=29). The participants were asked to emit a sustained vowel /a/ and raise the pitch gradually. Acoustic parameters, including F0, F0 SD, jitter, and shimmer, were recorded and analyzed.

RESULTS

The F0 SD was highest in the MF group. The F0 SD in the MF group and the ELC group was significantly higher than that in the VCP group and the control group (P<0.05), and the F0 SD in the VCP group was significantly higher than that in the control group (P<0.05). However, there was no significant difference in F0 SD between the MF group and the ELC group (P>0.05). The jitter and shimmer in the ELC group were significantly higher compared to the other groups (P<0.05), and the jitter and shimmer in the VCP group were significantly higher than those in the MF group and the control group (P<0.05). There were no significant differences in jitter or shimmer between the MF group and the control group (P>0.05).

CONCLUSIONS

F0 SD, jitter, and shimmer are important parameters for the evaluation of pitch variation during sustained phonations, and can discriminate between MF and voice disorders.