The Minimal Important Difference of Acoustic Voice Quality Index in the Treatment of Voice Disorders.

OBJECTIVES: The acoustic voice quality index (AVQI) is a reliable tool that objectively assesses dysphonia levels using six acoustic parameters. Despite its high criterion-related concurrent validity, diagnostic accuracy, and minimal detectable change derived from test-retest reliability, the minimal important difference (MID) of the AVQI has not been tested before. This study aimed to estimate the MIDs of AVQI for improvement audibly perceived by clinicians and self-reported improvement by patients. METHODS: A retrospective study was conducted on 110 patients who received treatment for voice disorders. Patients completed AVQI and Voice Handicap Index-10 (VHI-10) questionnaires before and after the therapy. The MIDs of the AVQI were estimated using the anchor of either auditory-perceptual judgment of total dysphonia levels by clinicians or the VHI-10 questionnaire by patients. A distribution-based approach was also used to complement the results. RESULTS: First, using the auditory-perceptual anchor, a decrease of 0.95 in the AVQI was estimated as the MID for clinicians' perception, as a result of the receiver operating curve. Then, using the patient-reported anchor, an improvement of 1.36 in the AVQI was estimated as the MID for patients' voice-related disability. The distribution-based approach also ensured the anchor-based results of both the MIDs. CONCLUSIONS: The AVQI is a reliable and valid tool for evaluating voice quality, and a 0.95 decrease in the AVQI represents a meaningful improvement for clinicians' perception, whereas a 1.36 decrease in the AVQI influences patients' self-reported disability. This study contributes to understanding the minimal change necessary for clinicians to make informed decisions and ensure patient satisfaction. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:2805-2811, 2024.

The Significant Influence of Hoarseness Levels in Connected Speech on the Voice-Related Disability Evaluated Using Voice Handicap Index-10.

OBJECTIVES: This retrospective study examines the influence of voice quality in connected speech (CS) and sustained vowels (SV) on the voice-related disability in patients' daily living documented by Voice Handicap Index-10 (VHI-10). METHODS: A total of 500 voice recordings of CS and SV samples from 338 patients with voice disturbances were included, along with the patients' age, diagnoses, maximum phonation time, and VHI-10. Dataset-1 comprised of 338 untreated patients, whereas Dataset-2 included 162 patients before and after phonosurgeries. As a preliminary study, the concurrent and diagnostic validities based on auditory-perceptual judgments were examined for cepstral peak prominence (CPP) and CPP smoothed (CPPS) for CS and SV tasks. Next, simple correlations and multivariate regression analyses (MRA) were performed to identify which of the acoustic measures for the CS or SV tasks significantly influenced the total score or improvement of VHI-10. RESULTS: The preliminary study confirmed high correlations with hoarseness levels as well as the excellent diagnostic accuracy of CPP and CPPS for both CS and SV tasks. In Dataset-1, the simple correlations and MRA results showed that cepstral measures in both tasks demonstrated moderate correlations with, and significant contribution to the total score of VHI-10, respectively. However, in Dataset-2, the changes of cepstral measures, as well as the median pitch after phonosurgeries in the CS tasks only, showed significant contributions to the improvement of VHI-10. CONCLUSION: The study demonstrated that the hoarseness levels in both the CS and SV tasks equivalently influenced the VHI-10 scores, and that the post-surgical change of voice quality only in the CS tasks influenced the improvement of voice-related disability in daily living.

Intertext Variability of Smoothed Cepstral Peak Prominence, Methods to Control It, and Its Diagnostic Properties.

OBJECTIVES: This study aimed to estimate the intertext variability of smoothed cepstral peak prominence (CPPS), examine whether sound-processing techniques improved its variability and diagnostic capability, and evaluate the degree of intertext variability in detail with reference to the CPPS variabilities in sustained vowels. STUDY DESIGN: This was a retrospective study. METHODS: Text readings of 58 Japanese syllables were recorded from 210 speakers with different diagnoses and varying degrees of dysphonia, and were divided into six passages. Applying the sound-processing techniques to those passages, we prepared three sample types: (1) nonprocessed, (2) only-loud, and (3) only-voiced samples. The intertext CPPS variability and diagnostic properties were compared across the passages and sample types. For detailed analysis, we subsequently extracted 63 normophonic speakers who maintained constant quality in their vowel utterances to evaluate the degree of intertext CPPS variability in relation to the variabilities between repeated identical vowels and across different vowels. RESULTS: Although several combinations of passages showed moderate-to-large CPPS variabilities, those variabilities were decreased by either technique, especially the deletion of silent segments, which resulted in the best diagnostic accuracy. The degree of intertext CPPS variability for the only-voiced samples was comparable to that of the CPPS variabilities in sustained vowels. CONCLUSIONS: The sound-processing technique removing silent segments should be applied to enhance the diagnostic properties of CPPS. The additional technique of deleting unvoiced segments is worth adopting if clinicians and researchers seek to attenuate the influence of text differences in calculating CPPS values.

Acoustic Breathiness Index for the Japanese-Speaking Population: Validation Study and Exploration of Affecting Factors.

Objectives The purposes of this study were to validate the Acoustic Breathiness Index (ABI) for the Japanese-speaking population and to determine whether it is independent of factors such as sex, age, and perceptual ratings of roughness. Method First, the concurrent validity of the ABI for perceptual breathiness was evaluated on the concatenations of continuous speech and sustained vowels from 288 patients with varying degrees of dysphonia. The diagnostic accuracy was examined on 343 samples with 55 additional normophonic speakers. Second, the validity related to responsiveness-to-change was estimated on 222 samples obtained before and after interventions for 111 voice-disordered patients. Third, the relationships between the ABI and other variables (i.e., perceptual hoarseness/breathiness/roughness, sex, and age) were explored using bivariate and multivariate analyses for the 288 patients. Results First, the concurrent validity and the responsiveness-to-change validity were confirmed by strong correlation coefficients of .890 and .878, respectively. Second, the receiver operating characteristic analysis showed the area under the curve to be 0.939, indicating excellent accuracy. The ABI of 3.44 exhibited a sensitivity of 76.3% and a specificity of 94.1%. Third, although bivariate analyses revealed a weak relationship between ABI and roughness and an ABI difference by age, multiple regression analyses showed a strong relation between only ABI and breathiness, without a meaningful contribution from roughness, sex, and age factors. Conclusion The study confirmed that the ABI is an accurate and specific tool to estimate breathiness levels in the Japanese-speaking population and neither roughness, sex, nor age significantly affects the ABI.

The Acoustic Voice Quality Index Version 03.01 for the Japanese-speaking Population.

OBJECTIVES: We aimed to determine the most appropriate syllable number for analyzing the Acoustic Voice Quality Index for the Japanese-speaking population (AVQIv3-JP) and to validate AVQIv3-JP using the determined syllable number. METHODS: First, we counted how many syllables should be included in each continuous speech (CS) sample to achieve time-balanced analysis between CS and sustained vowel samples using our previous dataset including 336 CS samples with 58 syllables. From the descriptive statistics of the counted syllable numbers, the most appropriate syllable number was identified. Subsequently, we performed validation procedures of AVQIv3-JP using our latest dataset including 455 recordings. RESULTS: Thirty Japanese syllables were judged to be the most appropriate syllable number. The concurrent validity of the AVQIv3-JP using 30 syllables was confirmed by Spearman's rho of 0.873. Subsequently, the receiver operating characteristic analysis demonstrated the excellent discriminative capability of AVQIv3-JP, showing the area under the curve of 0.915. The AVQIv3's original threshold of 2.43 in the Dutch language corresponded to sensitivity and specificity of 64.6% and 97.3%, respectively. In the present study, a threshold of 1.41 achieved the best accuracy with balanced sensitivity and specificity of 84.4% and 85.6%, respectively. Furthermore, the 95th percentile of the control participants exhibited a threshold of 2.06, showing sensitivity and specificity of 72.1% and 93.8%, respectively, as well as reasonable positive and negative likelihood ratios of 11.7 and 0.298, respectively. CONCLUSION: The AVQIv3 using 30 Japanese syllables is a reliable measurement tool for estimating the severity of voice quality and detecting abnormal voices.

Validation of the Acoustic Voice Quality Index in the Japanese Language.

OBJECTIVES: The Acoustic Voice Quality Index (AVQI) is a multivariate construct for quantification of overall voice quality based on the analysis of continuous speech and sustained vowel. The stability and validity of the AVQI is well established in several language families. However, the Japanese language has distinct characteristics with respect to several parameters of articulatory and phonatory physiology. The aim of the study was to confirm the criterion-related concurrent validity of AVQI, as well as its responsiveness to change and diagnostic accuracy for voice assessment in the Japanese-speaking population. STUDY DESIGN: This is a retrospective study. METHODS: A total of 336 voice recordings, which included 69 pairs of voice recordings (before and after therapeutic interventions), were eligible for the study. The auditory-perceptual judgment of overall voice quality was evaluated by five experienced raters. The concurrent validity, responsiveness to change, and diagnostic accuracy of the AVQI were estimated. RESULTS: The concurrent validity and responsiveness to change based on the overall voice quality was indicated by high correlation coefficients 0.828 and 0.767, respectively. Receiver operating characteristic analysis revealed an excellent diagnostic accuracy for discrimination between dysphonic and normophonic voices (area under the curve: 0.905). The best threshold level for the AVQI of 3.15 corresponded with a sensitivity of 72.5% and specificity of 95.2%, with the positive and negative likelihood ratios of 15.1 and 0.29, respectively. CONCLUSIONS: We demonstrated the validity of the AVQI as a tool for assessment of overall voice quality and that of voice therapy outcomes in the Japanese-speaking population.