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

Accuracy Analysis of the Multiparametric Acoustic Voice Indices, the VWI, AVQI, ABI, and DSI Measures, in Differentiating between Normal and Dysphonic Voices

The study aimed to investigate and compare the accuracy and robustness of the multiparametric acoustic voice indices (MAVIs), namely the Dysphonia Severity Index (DSI), Acoustic Voice Quality Index (AVQI), Acoustic Breathiness Index (ABI), and Voice Wellness Index (VWI) measures in differentiating normal and dysphonic voices. The study group consisted of 129 adult individuals including 49 with normal voices and 80 patients with pathological voices. The diagnostic accuracy of the investigated MAVI in differentiating between normal and pathological voices was assessed using receiver operating characteristics (ROC). Moderate to strong positive linear correlations were observed between different MAVIs. The ROC statistical analysis revealed that all used measurements manifested in a high level of accuracy (area under the curve (AUC) of 0.80 and greater) and an acceptable level of sensitivity and specificity in discriminating between normal and pathological voices. However, with AUC 0.99, the VWI demonstrated the highest diagnostic accuracy. The highest Youden index equaled 0.93, revealing that a VWI cut-off of 4.45 corresponds with highly acceptable sensitivity (97.50%) and specificity (95.92%). In conclusion, the VWI was found to be beneficial in describing differences in voice quality status and discriminating between normal and dysphonic voices based on clinical diagnosis, i.e., dysphonia type, implying the VWI's reliable voice screening potential.

Validation of Subharmonics Quantification Using Two-Stage Cepstral Analysis

OBJECTIVES

Hoarseness is primarily perceived as breathiness or roughness. Despite the various tools that quantitatively assess hoarseness, roughness has been difficult to quantify because of its complex acoustic structure, such as subharmonics. The parameter obtained from the two-stage cepstral analysis is promising for evaluating roughness. Thus, this study aimed to improve the accuracy of the parameter using a customized pitch setting and investigate the relationship between roughness and subharmonics.

STUDY DESIGN

The design is a retrospective study.

METHODS

Two-stage cepstral analysis was used to analyze the voice recordings of 455 participants, speech impaired and normal controls, using the Analysis of Dysphonia in Speech and Voice and Praat software. For validation, the ground truth of subharmonics was visually quantified using a narrowband spectrogram. The reliability and validity of the two-stage cepstral analysis and subharmonics measures on spectrograms were evaluated.

RESULTS

The two-stage cepstral analysis showed a very strong correlation (r = 0.963) between the two software programs. Intra- and inter-rater reliability of the subharmonics measures on spectrograms were also good. Two-stage cepstral analysis showed that even with customized pitch settings, the diagnostic systems and correlations for perceptual roughness and subharmonics were weak to moderate. The subharmonics measures on spectrograms showed a strong correlation with roughness and moderate diagnostic accuracy of subharmonics.

CONCLUSIONS

The two-stage cepstral analysis showed some improvement in diagnostic accuracy and correlation with customized pitch settings, but it did not sufficiently detect subharmonics or roughness. The analysis using subharmonics measures on spectrograms proved the high correlation between subharmonics and roughness, indicating that developing acoustic analysis parameters that sufficiently detect subharmonics is necessary.

Validation of the Acoustic Breathiness Index in Speakers of Finnish Language

Breathiness (perception of turbulence noise in the voice) is one of the major components of hoarseness in dysphonic voices. This study aims to validate a multiparameter analysis tool, the Acoustic Breathiness Index (ABI), for quantification of breathiness in the speaking voice, including both sustained vowels and continuous speech. One hundred and eight speakers with dysphonia (28 M, 80 F, mean age 50, SD 15.4 years) and 87 non-dysphonic controls (18 M, 69 F, mean age 42, SD 14 years) volunteered as participants. They read a standard text and sustained vowel /a:/. Acoustic recordings were made using a head-mounted microphone. Acoustic samples were evaluated perceptually by nine voice experts of different backgrounds (speech therapists, vocologists and laryngologists). Breathiness (B) from the GRBAS scale was rated. Headphones were used in the perceptual analysis. The dysphonic and non-dysphonic speakers differed significantly from each other in the auditory perceptual evaluation of breathiness. A significant difference was also found for ABI, which had a mean value of 2.26 (SD 1.15) for non-dysphonic and 3.07 (SD 1.75) for dysphonic speakers. ABI correlated strongly with B (rs = 0.823, p = 0.01). ABI's power to distinguish the groups was high (88.6%). The highest sensitivity and specificity of ABI (80%) was obtained at threshold value 2.68. ABI is a valid tool for differentiating breathiness in non-dysphonic and dysphonic speakers of Finnish.

The Performance of the Acoustic Voice Quality Index and Acoustic Breathiness Index in Synthesized Voices

OBJECTIVE

The aim of the present study was to investigate the performance of the Acoustic Voice Quality Index (AVQI) and the Acoustic Breathiness Index (ABI) in synthesized voice samples.

METHOD

The validity of the AVQI and ABI performances was analyzed in synthesized voice samples controlling the degree of predefined deviations for overall voice quality (G-scale) and breathiness (B-scale). A range of 26 synthesized voice samples with various severity degrees in G-scale with and without prominence of breathiness for male and female voices were created.

RESULTS

ABI received higher validity in the evaluation of breathiness than AVQI. Furthermore, ABI evaluated accurately breathiness degrees without considering roughness effects in voice samples and confirmed the findings of other studies with natural voices. Furthermore, ABI was more robust than AVQI in the evaluation of severe voice-disordered voice samples. Finally, AVQI represented moreover overall voice quality with an emphasis of breathiness evaluation and less roughness although roughness had a necessary component in overall voice quality evaluation.

CONCLUSION

AVQI and ABI are two robust measurements in the evaluation of voice quality. However, ABI received fewer errors than AVQI in the analyses of higher abnormalities in the voice signal. Disturbances of other subtypes of abnormal overall voice quality such as roughness were not demonstrated in the results of ABI.

Test-Retest Reliability of the Acoustic Voice Quality Index and the Acoustic Breathiness Index

OBJECTIVE

The acoustic voice quality index (AVQI) and the acoustic breathiness index (ABI) are two validated measurements for the objective-acoustic assessment of voice quality. The aim of this study was to evaluate the relative and absolute reliability of AVQI and ABI as well as detect the natural variability of vocally-healthy voices.

METHODS

Totally, 39 vocally-healthy participants received weekly an AVQI- and ABI measurement using the freeware VOXplot over a period of 3 weeks. This study is a within-subject design to assess significant differences between the test and retest measurements (test and mean of two retests) of AVQI and ABI with the paired sample t test and to investigate the reliability of these two acoustic parameters with the intraclass correlation coefficient (ICC), Bland-Altman plot, and the minimal detectable change (MDC).

RESULTS

No significant differences between the test-retest measurements of AVQI and ABI were revealed (all P-values > 0.05). The relative reliability of AVQI and ABI showed good results (eg, ICC = 0.81, and ICC = 0.92, respectively). Absolute reliability measured with the MDC yielded a test-retest value of 0.78 and 0.66 for the AVQI and ABI, respectively. Deviations within this range may be due to natural variations of the voice (random bias).

CONCLUSION

AVQI and ABI revealed high-reliability results in a test-retest measurement of vocally-healthy participants.

Formant-Aware Spectral Analysis of Sustained Vowels of Pathological Breathy Voice

OBJECTIVES

This paper reports the effectiveness of formant-aware spectral parameters to predict the perceptual breathiness rating. A breathy voice has a steeper spectral slope and higher turbulent noise than a normal voice. Measuring spectral parameters of acoustic signals over lower formant regions is a known approach to capture the properties related to breathiness. This study examines this approach by testing the contemporary spectral parameters and algorithms within the framework, alternate frequency band designs, and vowel effects.

METHODS

Sustained vowel recordings (/a/, /i/, and /u/) of speakers with voice disorders in the German Saarbrueken Voice Database were considered (n: 367). Recordings with signal irregularities, such as subharmonics or with roughness perception, were excluded from the study. Four speech language pathologists perceptually rated the recordings for breathiness on a 100-point scale, and their averages were used in the analysis. The acoustic spectra were segmented into four frequency bands according to the vowel formant structures. Five spectral parameters (intraband harmonics-to-noise ratio, HNR; interband harmonics ratio, HHR; interband noise ratio, NNR; and interband glottal-to-noise energy, GNE, ratio) were evaluated in each band to predict the perceptual breathiness rating. Four HNR algorithms were tested.

RESULTS

Multiple linear regression models of spectral parameters, led by the HNRs, were shown to explain up to 85% of the variance in perceptual breathiness ratings. This performance exceeded that of the acoustic breathiness index (82%). Individually, the HNR over the first two formants best explained the variances in the breathiness (78%), exceeding the smoothed cepstrum peak prominence (74%). The performance of HNR was highly algorithm dependent (10% spread). Some vowel effects were observed in the perceptual rating (higher for /u/), predictability (5% lower for /u/), and model parameter selections.

CONCLUSIONS

Strong per-vowel breathiness acoustic models were found by segmenting the spectrum to isolate the portion most affected by breathiness.

Voice Quality in Telephone Interviews: A preliminary Acoustic Investigation

OBJECTIVES

To investigate the impact of standardized mobile phone recordings passed through a telecom channel on acoustic markers of voice quality and on its perception by voice experts in normophonic speakers.

METHODS

Continuous speech and a sustained vowel were recorded for fourteen female and ten male normophonic speakers. The recordings were done simultaneously with a head-mounted high-quality microphone and through the telephone network on a receiving smartphone. Twenty-two acoustic voice quality, breathiness and pitch-related measures were extracted from the recordings. Nine vocologists perceptually rated the G, R and B parameters of the GRBAS scale on each voice sample. The reproducibility, the recording type, the stimulus type and the gender effects, as well as the correlation between acoustic and perceptual measures were investigated.

RESULTS

The sustained vowel samples are damped after one second. Only the frequencies between 100 and 3700Hz are passed through the telecom channel and the frequency response is characterized by peaks and troughs. The acoustic measures show a good reproducibility over the three repetitions. All measures significantly differ between the recording types, except for the local jitter, the harmonics-to-noise ratio by Dejonckere and Lebacq, the period standard deviation and all six pitch measures. The AVQI score is higher in telephone recordings, while the ABI score is lower. Significant differences between genders are also found for most of the measures; while the AVQI is similar in men and women, the ABI is higher in women in both recording types. For the perceptual assessment, the interrater agreement is rather low, while the reproducibility over the three repetitions is good. Few significant differences between recording types are observed, except for lower breathiness ratings on telephone recordings. G ratings are significantly more severe on the sustained vowel on both recording types, R ratings only on telephone recordings. While roughness is rated higher in men on telephone recordings by most experts, no gender effect is observed for breathiness on either recording types. Finally, neither the AVQI nor the ABI yield strong correlations with any of the perceptual parameters.

CONCLUSIONS

Our results show that passing a voice signal through a telecom channel induces filter and noise effects that limit the use of common acoustic voice quality measures and indexes. The AVQI and ABI are both significantly impacted by the recording type. The most reliable acoustic measures seem to be pitch perturbation (local jitter and period standard deviation) as well as the harmonics-to-noise ratio from Dejonckere and Lebacq. Our results also underline that raters are not equally sensitive to the various factors, including the recording type, the stimulus type and the gender effects. Neither of the three perceptual parameters G, R and B seem to be reliably measurable on telephone recordings using the two investigated acoustic indexes. Future studies investigating the impact of voice quality in telephone conversations should thus focus on acoustic measures on continuous speech samples that are limited to the frequency response of the telecom channel and that are not too sensitive to environmental and additive noise.

Validation of Acoustic Breathiness Index (ABI) in the South Indian Population

BACKGROUND

Acoustic Breathiness Index (ABI) is an acoustic model which equates to the auditory-perceptual (A-P) measure of breathiness. Globally, ABI has been validated in multiple languages. To date, empirical studies validating ABI in the South Indian population have not been carried out. Moreover, there is only minimal evidence on the impact of language and gender on ABI.

OBJECTIVES

This study attempted to validate ABI in languages of Malayalam and Kannada with "B" and "G" of GRBAS. The authors also examined the influence of language and gender on ABI.

METHODS

The authors retrospectively analyzed a dataset consisting of 160 voice samples (91 normophonic and 69 dysphonic). Five speech-language pathologists perceptually evaluated these samples on the GRBAS scale. PRAAT software was used to calculate ABI for each voice sample. The authors also determined the effects of language and gender on ABI. Following this, ABI's concurrent validity and diagnostic accuracy were examined relating to "B" and "G" of the GRBAS scale.

RESULTS

The judges reached a moderate agreement on the perceptual evaluation of voice quality. The authors observed neither language nor gender differences in ABI. The concurrent validity of ABI was strong (r = 0.761) when correlated against "B". Further, evaluations revealed that an ABI value of >3.66 could distinguish between breathy and non-breathy voice samples with an area under the curve of 0.816 (Sensitivity = 61.73%; Specificity = 94.93%). On the other hand, the concurrent validity of ABI in correlation with "G" did not yield the optimal result.

CONCLUSIONS

ABI is a valid acoustic tool for identifying breathiness in the languages of Malayalam and Kannada. ABI correlates better with "B" than "G" on the GRBAS scale. ABI is independent of language and gender.

The cepstral spectral index of dysphonia, the acoustic voice quality index and the acoustic breathiness index as novel multiparametric indices for acoustic assessment of voice quality

PURPOSE OF REVIEW

The objective assessment of voice quality using acoustic measures is an important pillar of voice diagnostics. This article reviews three recent acoustic measures and their clinical use in phoniatrics and laryngology.

RECENT FINDINGS

Two acoustic parameters, the cepstral spectral index of dysphonia (CSID) and the acoustic voice quality index (AVQI), have gained importance as validated multiparametric indices in the objective assessment of hoarseness because they include both continuous speech and sustained vowels. The acoustic breathiness index (ABI), another multiparametric index, assesses breathiness admixture during phonation and identifies it robustly, unaffected by other characteristics of dysphonia such as roughness.

SUMMARY

Acoustic measurements are useful diagnostic tools when used correctly with an appropriate recording system, consideration of environment and use of software programs. CSID, AVQI and ABI objectively improve the detection of voice quality abnormalities. In addition to their proven validity, their application is simple and their usability for clinicians is high.

Objective Analysis Of Voice Quality In Patients With Thyroid Pathology

OBJECTIVE

The goal of this study is to analyze the voice in patients with thyroid pathology through two objective indexes with great diagnostic accuracy. Overall vocal quality was evaluated with the Acoustic Voice Quality Index (AVQI v.03.01) and the breathy voice with the Acoustic Breathiness Index (ABI).

DESIGN

Observational case-control study.

SETTING

Hospital Universitario Nuestra Señora de Candelaria.

PARTICIPANTS

Fifty-eight subjects, 29 controls and 29 thyroidectomy candidates.

MAIN OUTCOME MEASURES

All participants with thyroid pathology completed the Spanish version of Voice Handicap Index-10. Also, patient complaints relating to possible laryngeal dysfunction were assessed through closed questions. A sustained vowel and three phonetically balanced sentences were recorded for each subject (118 samples). AVQI v.03.01 and ABI were assessed using the Praat program. Two raters perceptually evaluated each voice sample by using the Grade parameter of GRABS scale.

RESULTS

Acoustic analysis shows that 55.17% of subjects present values above the pathological threshold of the AVQI, and 58.62% above that of the ABI. Results of the Student's test comparisons of the AVQI and ABI values between the control group and the thyroid group show significantly higher values of AVQI (t_[56]  = -3.85, p < .001) and ABI (t_[54.39]  = -4.82, p < .001) in thyroidectomy candidates.

CONCLUSION

A mild decrease in vocal quality is part of the symptomatology presented by thyroidectomy candidates.

Validation of the acoustic breathiness index to the Brazilian Portuguese language

OBJECTIVE

To assess the concurrent validity and the diagnostic accuracy of the Acoustic Breathiness Index (ABI) in Brazilian Portuguese.

METHODS

The counting numbers 1-20 and the vowel /a/ of 150 subjects were recorded (37 vocally healthy and 113 with dysphonia). The analyzed samples were the counting number 1-11 and 3 s of the sustained vowel. Nine voice specialists performed the perceptual judgment of the degree of breathiness. The Spearman Correlation and the receiver operating characteristic (ROC) curve were used to assess ABI's concurrent validity and diagnosis accuracy.

RESULTS

Results from five listeners were chosen for the study analyses due to moderate and substantial intra-rater reliability (Cohen's Kappa values = 0.520-0.772) and moderate inter-rater reliability (Fleiss Kappa = 0.353). The ABI presented a high concurrent validity (r = 0.746); 55.6% of the breathiness vocal deviation can be explained by the acoustic analysis (r² = 0.556). The ROC curve presented good diagnostic accuracy (85.2%). At a threshold of 2.94, the sensitivity was 75.3% and the specificity was 93.4%.

CONCLUSION

The ABI is a valid tool for screening and patient's follow-up regarding breathy vocal qualities in the Brazilian Portuguese language.

The validity of the Acoustic Breathiness Index in the evaluation of breathy voice quality: A Meta-Analysis

BACKGROUND

The evaluation of voice quality with acoustic measurements is useful to objectify the diagnostic process. Particularly, breathiness was highly evaluated and the Acoustic Breathiness Index (ABI) might have promising features.

OBJECTIVE OF REVIEW

The goal of the present meta-analysis is to quantify, from existing cross-validation studies, the evidence for the diagnostic accuracy of ABI, including its sensitivity and specificity.

TYPE OF REVIEW

Meta-analysis.

SEARCH STRATEGY

We searched in MEDLINE, Google Scholar and Science Citation Index, and as manual search for the term Acoustic Breathiness Index from inception to February 2020. Studies were included that used equal proportion of continuous speech and sustained vowel segments, a recording hardware with a sufficient standard for voice signal analyses, the software Praat for signal processing and the customised Praat script, and two groups of subjects (vocally healthy and voice-disordered). Furthermore, the diagnostic accuracy of ABI was measured.

EVALUATION METHOD

The primary outcome variable was ABI. The score ranged from 0 to 10 with varying thresholds according to different languages to determine the absence or presence of breathiness. A meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses of diagnostic test accuracy study guidelines. Data were extracted, and the risk of bias was assessed using the QUADAS-2 tool. The pooled sensitivity and specificity of ABI were determined using a summary receiver operating characteristic (SROC) approach to calculate also a weighted threshold value of ABI with its sensitivity and specificity.

RESULTS

A total of 34 unique citations were screened, and 10 full-text articles were reviewed, including six studies. In total, 3603 voice samples were considered for further analysis separating into 467 vocally healthy and 3136 voice-disordered voice samples. The pooled sensitivity was 0.84 (95% CI, 0.83-0.85), and the pooled specificity was 0.92 (95% CI, 0.89-0.94). The area under the curve of the SROC curve of this analysis showed an excellent value of 0.94. The weighted ABI threshold was determined at 3.40 (sensitivity: 0.86, 95% CI, 0.84-0.87.; specificity: 0.90, 95% CI 0.88-0.92).

CONCLUSIONS

The results confirm the ABI as robust and valid objective measure for evaluating breathiness.