Establishment And Clinical Application Of Evaluation System Of Voice Quality

Nowadays there is much concern about voice health with the improvement of social communication and living standard. Perceptual evaluation of voice quality is the most widely used evaluation methods. But the reliability of evaluation results was influenced by the immanent subjectivity and some correlation factors. The objective assessment makes it possible to evaluate voice quality objectively and quantitatively. The validity of acoustic assessments in clinical applications remains unproven, clinical data have not shown that jitter and shimmer are absolute or independent indices of voice pathology or perceptual hoarseness. The true value of clinical acoustic analysis might be masked by the confounding effects due to assessment system, gender, the method and status of phonation. Reasonable application of different parameters to evaiuate voice quality is needed.According to the above-mentioned backgrounds, we carried on some studies as follows:①Study on the stability of perceptual evaluation of voice quality;②Establish of male and female objective multi-parameters models of voice quality and test of its stability.Objective1. To explore the factors that influence the stability of evaluation results judged by a jury through a standard research on perceptual evaluation measurements of voice quality.2. To explore the gender variability of objective parameters and the correlation with perceptual evaluation of voice quality, and to establish an objective multi-parameters model with research and clinical practicality, then make the evaluation of voice objectification and quantification.Methods1. Voice samples from 300 patients with dysphonia and 100 control subjects with normal voice were recorded and assessed by a jury composed of 6 experienced listeners from different hospitals. The voice samples were discourse voices and ordered randomly 3 times and the mean of 3 evaluations using visual analogue scale were the final results. The jury was instructed to classify voice samples according to the G (grade), R (rough) and B(breathy) components of the GRBAS scale on a 4-point scale ranging from 0 for normal to 3 for severe dysphonia. Kappa value was used to analyze the concordance of evaluation results and regression analysis was used to research the effects of the extent of voice disorder to the stability of perceptual evaluation.2. Objective parameters including F0, jitter, shimmer, FOSD, NNE, HNR and MPT from 271 patients with dysphonia and 69 control subjects with normal voice were measured. And the voice samples of those people were assessed by a jury composed of 5 experienced listeners from different hospitals. The voice samples were discourse voices and ordered randomly 3 times and the mean of 3 evaluations using visual analogue scale were the final results. The jury was instructed to classify voice samples according to the G components of the GRBAS scale on a 4-point scale ranging from 0 for normal to 3 for severe dysphonia. The gender variability of objective parameters and the correlation among those parameters were analyzed, then discriminant analysis were used to establish the objective multi-parameters models of voice quality, and the probability of voice grading was calculated using discriminant function.3. Objective parameters including F0, jitter, shimmer, FOSD, NNE, HNR and MPT from 170 patients with dysphonia and 13 control subjects with normal voice were measured. And the voice samples of those people were assessed by a jury composed of 5 experienced listeners from different hospitals. The voice samples were discourse voices and ordered randomly 3 times and the mean of 3 evaluations using visual analogue scale were the final results. The jury was instructed to classify voice samples according to the G components of the GRBAS scale on a 4-point scale ranging from 0 for normal to 3 for severe dysphonia. The probability of voice grading was calculated using the discriminant function which had been established before.Results1. Results of perceptual evaluation of voice quality:The discordance of evaluation exists both between the jury and in listeners themselves. The concordance of listeners themselves of each evaluation parameter was not bad, good, or even very good, and the concordance of evaluation of G was the best(kαppαvalue:0.46～0.85), then R(kαppαvalue:0.41～0.84) and B(kαppαvalue:0.41～0.81). The concordance between the jury was worse than that in themselves. And except a listener whose concordance of evaluation was under the requirement, the concordance of evaluation of G was the best(kappa value:0.43～0.96), then R(kappa value:0.33～0.78) and B(kappa value:0.002～0.45). The stability of evaluation of normal voice and severe voice disorder was better than mild and moderate voice disorder.2. Results of gender variability of objective assessment parameters:①In normal voice group, F0, FOSD, NNE and MPT had gender variability.②In mild voice disorder group, all parameters except for MPT had gender variability.③In moderate voice disorder group, all parameters except for jitter had gender variability.④In severe voice disorder group, all parameters except for FOSD and MPT had gender variability.3. Results of the establishment of objective multi-parameters models:①All parameters except for F0 had high correlation with G and the variance tendency of these parameters values was coherent with the extent of voice disorder, and there were statistical differences between adjacent groups. The correlation of NNE and HNR with G were the best to male, while MPT and NNE were the best to female.②The concordance of perceptual evaluation and objective multi-parameters evaluation was 81.6% to male, and in normal, mild, moderate and severe voice disorder group, it was 93.8%,75.4%,80.9% and 85.7% respectively.③The concordance of perceptual evaluation and objective multi-parameters evaluation was 83.2% to female, and in normal, mild, moderate and severe voice disorder group, it was 93.2%,77.8%,80.5% and 84.6% respectively. All mis-grading voices were in the adjacent voice group.4. Results of the verification of objective multi-parameters models:The concordance of perceptual evaluation and objective multi-parameters evaluation was 85.3% to male and 83.0% to female.Conclusion1. The discordance between the jury was the main factor that influences the stability of perceptual evaluation. The evaluation parameters and extent of voice disorder will influence the stability of perceptual evaluation of the jury.2. Gender differences of objective parameters in voice disorder groups were obviously than in normal voice group.3. Male and female objective multi-parameters models were established respectively consist of jitter, shimmer, FOSD, NNE, HNR and MPT using discriminant analysis. And the concordance of perceptual evaluation and objective multi-parameters evaluation was good (more than 80%).4. The application of discriminant probability made up the disadvantage of 4-point scale, and made the evaluation of voice disorder more perfect and accurate.5. We established an objective multi-parameters model with research and clinical practicality, it will help to avoid complicated and time consuming perceptual evaluation, and made the evaluation of voice objectification and quantification.