Youri Maryn

Toward Improved Ecological Validity in the Acoustic Measurement of Overall Voice Quality: Combining Continuous Speech and Sustained Vowels

To improve ecological validity, perceptual and instrumental assessment of disordered voice, including overall voice quality, should ideally sample both sustained vowels and continuous speech. This investigation assessed the utility of combining both voice contexts for the purpose of auditory-perceptual ratings as well as acoustic measurement of overall voice quality. Sustained vowel and continuous speech samples from 251 subjects with (n=229) or without (n=22) various voice disorders were concatenated and perceptually rated on overall voice quality by five experienced voice clinicians. After removing the nonvoiced segments within the continuous speech samples, the concatenated samples were analyzed using 13 acoustic measures based on fundamental frequency perturbation, amplitude perturbation, spectral and cepstral analyses. Stepwise multiple regression analysis yielded a six-variable acoustic model for the multiparametric measurement of overall voice quality of the concatenated samples (with a cepstral measure as the main contributor to the prediction of overall voice quality). The correlation of this model with mean ratings of overall voice quality resulted in r(s)=0.78. A cross-validation approach involving the iterated internal cross-correlations with 30 subgroups of 100, 50, and 10 samples confirmed a comparable degree of association. Furthermore, the ability of the model to distinguish voice-disordered from vocally normal participants was assessed using estimates of diagnostic precision including receiver operating characteristic (ROC) curve analysis, sensitivity, and specificity, as well as likelihood ratios (LRs), which adjust for base-rate differences between the groups. Depending on the cutoff criteria employed, the analyses revealed an impressive area under ROC=0.895 as well as respectable sensitivity, specificity, and LR. The results support the diagnostic utility of combining voice samples from both continuous speech and sustained vowels in acoustic and perceptual analysis of disordered voice. The findings are discussed in relation to the extant literature and the need for further refinement of the acoustic algorithm.

Acoustic measurement of overall voice quality: A meta-analysisa)

Over the past several decades, many acoustic markers have been proposed to be sensitive to and measure overall voice quality. This meta-analysis presents a retrospective appraisal of scientific reports, which evaluated the relation between perceived overall voice quality and several acoustic-phonetic correlates. Twenty-five studies met the inclusion criteria and were evaluated using meta-analytic techniques. Correlation coefficients between perceptual judgments and acoustic measures were computed. Where more than one correlation coefficient for a specific acoustic marker was available, a weighted average correlation coefficient was calculated. This was the case in 36 acoustic measures on sustained vowels and in 3 measures on continuous speech. Acoustic measures were ranked according to the strength of the correlation with perceptual voice quality ratings. Acoustic markers with more than one correlation value available in literature and yielding a homogeneous weighted r of 0.60 or above were considered to be superior. The meta-analysis identified four measures that met these criteria in sustained vowels and three measures in continuous speech. Although acoustic measures are routinely utilized in clinical voice examinations, the results of this meta-analysis suggest that caution is warranted regarding the concurrent validity and thus the clinical utility of many of these measures.

The Acoustic Voice Quality Index: Toward improved treatment outcomes assessment in voice disorders

UNLABELLED Voice practitioners require an objective index of dysphonia severity as a means to reliably track treatment outcomes. To ensure ecological validity however, such a measure should survey both sustained vowels and continuous speech. In an earlier study, a multivariate acoustic model referred to as the Acoustic Voice Quality Index (AVQI), consisting of a weighted combination of 6 time-, frequency- and quefrency-domain metrics, was developed to measure dysphonia severity in both speaking tasks. In the current investigation, the generalizability and clinical utility of the AVQI are evaluated by first assessing its external cross-validity and then determining its sensitivity to change in dysphonia severity following surgical and/or behavioral voice treatment. The results, based upon a new set of normal and disordered voices compared favorably with outcomes reported earlier, indicating acceptable external validity. Furthermore, the AVQI was sensitive to treatment-related changes, validating its role as a potentially robust and objective voice treatment outcomes measure. LEARNING OUTCOMES Readers will be able to: (1) explain methodological issues surrounding the development of voice treatment outcomes measures (such as external cross-validity and responsiveness to change), (2) appreciate the relevance of measuring dysphonia severity in both sustained vowels and connected speech, (3) describe the method of obtaining the Acoustic Voice Quality Index (AVQI), (4) appreciate differences among a variety of estimates of diagnostic accuracy, and (5) discuss the AVQI as a clinically valid treatment outcomes measure.

Perturbation Measures of Voice: A Comparative Study between Multi-Dimensional Voice Program and Praat

Background/Aims: Frequency and amplitude perturbations are inherent in voice acoustic signals. The assessment of voice perturbation is influenced by several factors, including the type of recording equipment used and the measurement extraction algorithm applied. In the present study, perturbation measures provided by two computer systems (a purpose-built professional voice analysis apparatus and a personal computer-based system for acoustic voice assessment) and two computer programs (Multi-Dimensional Voice Program and Praat) were compared. Methods: Correlations and inferential statistics for seven perturbation measures (absolute jitter, percent jitter, relative average perturbation, pitch perturbation quotient, shimmer in decibels, percent shimmer, and amplitude perturbation quotient) in 50 subjects with various voice disorders are presented. Results: Results indicate statistically significant differences between the two systems and programs, with the Multi-Dimensional Voice Program yielding consistently higher measures than Praat. Furthermore, correlation analyses show weak to moderate proportional relationships between the two systems and weak to strong proportional relationships between the two programs. Conclusion: Based on the literature and the proportional relationships and differences between the two systems and programs under consideration in this study, one can state that one can hardly compare frequency perturbation outcomes across systems and programs and amplitude perturbation outcomes across systems.

Objective assessment of pediatric voice disorders with the acoustic voice quality index

OBJECTIVES/HYPOTHESIS Instrumental measures of voice allow practitioners to assess the severity of voice disorders and objectively measure treatment outcomes. Instrumental measures should be calculated on both sustained vowel and connected speech samples to ensure ecological validity. However, there is a lack of appropriate, validated acoustic measurements for use in the pediatric population. The Acoustic Voice Quality Index (AVQI) is a multivariate acoustic measure of dysphonia that has been found to be reliable, valid, and have diagnostic accuracy and response to change in an adult population. This study aimed to evaluate the AVQI in a pediatric population. STUDY DESIGN This study was a prospective observational study of a sample of dysphonic and normophonic children. METHODS Sixty-seven preterm participants (born at less than 25 weeks gestation) aged between 6 and 15 years were recruited. Participants were excluded because of either inability to comply with task requirements or other speech-related factors that affected acoustic measurement. Forty normophonic term-born participants aged between 5 and 15 years were also recruited. AVQI analysis was conducted on a prolonged vowel sample and a sample of continuous speech. RESULTS The AVQI was found to have diagnostic accuracy and specificity in this population of children with and without dysphonia. It was moderately correlated with ratings of severity on the GRBAS (overall grade of hoarseness (G), roughness (R), breathiness (B), aesthenicity (A), and strain (S)), a subjective rating scale. The threshold for pathology of this sample of 3.46 showed strong sensitivity, specificity, and accuracy, with good-to-excellent likelihood ratios. CONCLUSIONS This study found that the AVQI has diagnostic accuracy in a pediatric population, suggesting that it is an appropriate assessment tool to determine the presence and severity of pediatric voice disorders.

Ventricular Dysphonia: Clinical Aspects and Therapeutic Options

Objective/Hypothesis Ventricular dysphonia, also known as dysphonia plica ventricularis, refers to the pathological interference of the false vocal folds during phonation. Despite its low incidence and prevalence, Vd is a well‐known phenomenon in voice clinics. The present report reviews symptoms, etiology, diagnosis, and therapeutic options regarding this voice disorder.

Spectral, cepstral, and multivariate exploration of tracheoesophageal voice quality in continuous speech and sustained vowels.

The quality of tracheoesophageal voice can vary substantially. Although previous research has identified acoustic differences between various types of voicing (i.e., laryngeal, tracheoesophageal, esophageal, etc.), acoustic analysis has failed to quantify the degree of alaryngeal voice quality. This study assessed the value of several cepstral, spectral, and perturbation measures in quantifying the overall quality of tracheoesophageal voice production.

External Validation of the Acoustic Voice Quality Index Version 03.01 With Extended Representativity

Objectives: The Acoustic Voice Quality Index (AVQI) is an objective method to quantify the severity of overall voice quality in concatenated continuous speech and sustained phonation segments. Recently, AVQI was successfully modified to be more representative and ecologically valid because the internal consistency of AVQI was balanced out through equal proportion of the 2 speech types. The present investigation aims to explore its external validation in a large data set. Methods: An expert panel of 12 speech-language therapists rated the voice quality of 1058 concatenated voice samples varying from normophonia to severe dysphonia. The Spearman rank-order correlation coefficients (r) were used to measure concurrent validity. The AVQI’s diagnostic accuracy was evaluated with several estimates of its receiver operating characteristics (ROC). Results: Finally, 8 of the 12 experts were chosen because of reliability criteria. A strong correlation was identified between AVQI and auditoryperceptual rating (r = 0.815, P = .000). It indicated that 66.4% of the auditory-perceptual rating’s variation was explained by AVQI. Additionally, the ROC results showed again the best diagnostic outcome at a threshold of AVQI = 2.43. Conclusions: This study highlights external validation and diagnostic precision of the AVQI version 03.01 as a robust and ecologically valid measurement to objectify voice quality.

The improvement of internal consistency of the Acoustic Voice Quality Index

PURPOSE This investigation aims to explore the improvement of the relatively new hoarseness severity quantification method, called Acoustic Voice Quality Index (AVQI), which measures the concatenation of continuous speech (CS) and sustained phonation (SP) segments. Earlier investigations indicated that the proportion of the SP is more dominant in the final AVQI result than the CS. METHOD Sixty voice samples were selected with different voice pathologies and equal distribution of hoarseness severity ranged from normal to severe. Every voice sample varied in three different durations: voice duration-one (VD-1) with seventeen syllables text plus three seconds of SP, voice duration-two (VD-2) with customized length of CS plus three seconds of SP, and voice duration-three (VD-3) with a whole text plus three seconds SP. All voice samples were perceptually judged on overall voice quality by five experienced voice clinicians. AVQIs precision and concurrent validity were assessed in all three VDs. Finally, the internal consistency across all three VDs was analyzed. RESULTS No significant differences were found in the perceptual evaluation of overall voice quality across all three VDs by acceptable rater reliability. The concurrent validity distinguished in all three VDs as a marked degree of correlation (i.e., ranged from rs=0.891 to rs=0.929) with no significant differences across all three VDs. The best precision was found in VD-2. Finally, the internal consistency showed in VD-2 a balanced out impact of the final AVQI score with no significant differences from both speech tasks. CONCLUSION Although AVQI currently uses the speech material of VD-1, the present study demonstrated the best results in VD-2 (i.e., precision and internal consistency). These features of VD-2 facilitate higher representativity and improve the validity of this objective diagnostic instrument.

The effects of adenoidectomy and tonsillectomy on speech and nasal resonance

This article presents a review of literature concerning speech and nasal resonance following adenoidectomy and/or tonsillectomy. In order to comprehend speech-related postoperative changes, the role of the adenoid and the tonsils in speech is discussed as well as the concept of veloadenoidal closure separating oral and nasal cavities. Moreover, the effects of adenoidal and tonsillar hypertrophy on speech and nasal resonance are debated.