Cepstral- and Spectral-Based Acoustic Measures of Normal Voices

A review of recent literature suggested that cepstral- and spectral-based acoustic measures showed good potential as objective measures of dysphonia for clinical application. However, the small numbers of normal subjects in previous research and wide age ranges prevent a good estimation of the performance of normal speakers of various ages on these measures. Therefore, the purpose of this study was to provide normative data for Long-Term Average spectral- and cepstral-based measures for both men and women in two different age groups to aid clinicians with assessing and treating voice disorders. Sixty participants consisting of fifteen males and fifteen females, ages 20-30 years, and fifteen males and fifteen females, ages 40-50 years contributed speech samples to be analyzed in this study. Speakers were asked to sustain the vowels /a/ and /i/, read out loud four CAPE-V stimulus sentences, and the 2nd and 3rd sentence of the Rainbow Passage. Dependent variables were Cepstral Peak Prominence (CPP), Low-to-High Spectral Ratio (L/H spectral ratio), and Cepstral Peak Prominence Fundamental Frequency (CPP F0) for both vowels and connected speech. Male voice quality (CPP and L/H spectral ratio) was better in vowels /a/ and /i/, but female voice quality was better (CPP values) for connected speech. Age did not affect voice quality for vowels /a/ and /i/; however, it did affect it for connected speech. Younger speakers had better voice quality (CPP) than older speakers. In general, for both vowels and connected speech, younger women had markedly higher CPP F0 values than older women, while older men had slightly higher CPP F0 values compared to younger men. It was concluded that separate normative data should be applied clinically for all four age/gender groups. The maximum limit of the ADSV extraction range for male participants should be changed from 300 Hz to 200 Hz for connected speech readings to obtain accurate CPP F0 measures. Furthermore, due to limited research, data should be analyzed both with and without vocalic detection until it becomes clear which one is more valid. Further research is recommended to improve both the procedures and reference data available for voice quality

Acoustic measurement of overall voice quality in sustained vowels and continuous speech

Measurement of dysphonia severity involves auditory-perceptual evaluations and acoustic analyses of sound waves. Meta-analysis of proportional associations between these two methods showed that many popular perturbation metrics and noise-to-harmonics and others ratios do not yield reasonable results. However, this meta-analysis demonstrated that the validity of specific autocorrelation- and cepstrum-based measures was much more convincing, and appointed ‘smoothed cepstral peak prominence’ as the most promising metric of dysphonia severity. Original research confirmed this inferiority of perturbation measures and superiority of cepstral indices in dysphonia measurement of laryngeal-vocal and tracheoesophageal voice samples. However, to be truly representative for daily voice use patterns, measurement of overall voice quality is ideally founded on the analysis of sustained vowels ánd continuous speech. A customized method for including both sample types and calculating the multivariate Acoustic Voice Quality Index (i.e., AVQI), was constructed for this purpose. Original study of the AVQI revealed acceptable results in terms of initial concurrent validity, diagnostic precision, internal and external cross-validity and responsiveness to change. It thus was concluded that the AVQI can track changes in dysphonia severity across the voice therapy process. There are many freely and commercially available computer programs and systems for acoustic metrics of dysphonia severity. We investigated agreements and differences between two commonly available programs (i.e., Praat and Multi-Dimensional Voice Program) and systems. The results indicated that clinicians better not compare frequency perturbation data across systems and programs and amplitude perturbation data across systems. Finally, acoustic information can also be utilized as a biofeedback modality during voice exercises. Based on a systematic literature review, it was cautiously concluded that acoustic biofeedback can be a valuable tool in the treatment of phonatory disorders. When applied with caution, acoustic algorithms (particularly cepstrum-based measures and AVQI) have merited a special role in assessment and/or treatment of dysphonia severity

Models and Analysis of Vocal Emissions for Biomedical Applications

The MAVEBA Workshop proceedings, held on a biannual basis, collect the scientific papers presented both as oral and poster contributions, during the conference. The main subjects are: development of theoretical and mechanical models as an aid to the study of main phonatory dysfunctions, as well as the biomedical engineering methods for the analysis of voice signals and images, as a support to clinical diagnosis and classification of vocal pathologies

Optimizing acoustic and perceptual assessment of voice quality in children with vocal nodules

Thesis (Ph. D.)--Harvard-MIT Division of Health Sciences and Technology, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 105-109).Few empirically-derived guidelines exist for optimizing the assessment of vocal function in children with voice disorders. The goal of this investigation was to identify a minimal set of speech tasks and associated acoustic analysis methods that are most salient in characterizing the impact of vocal nodules on vocal function in children. Hence, a pediatric assessment protocol was developed based on the standardized Consensus Auditory Perceptual Evaluation of Voice (CAPE-V) used to evaluate adult voices. Adult and pediatric versions of the CAPE-V protocols were used to gather recordings of vowels and sentences from adult females and children (4-6 and 8-10 year olds) with normal voices and vocal nodules, and these recordings were subjected to perceptual and acoustic analyses. Results showed that perceptual ratings for breathiness best characterized the presence of nodules in children's voices, and ratings for the production of sentences best differentiated normal voices and voices with nodules for both children and adults. Selected voice quality-related acoustic algorithms designed to quantitatively evaluate acoustic measures of vowels and sentences, were modified to be pitch-independent for use in analyzing children's voices. Synthesized vowels for children and adults were used to validate the modified algorithms by systematically assessing the effects of manipulating the periodicity and spectral characteristics of the synthesizer's voicing source.(cont.) In applying the validated algorithms to the recordings of subjects with normal voices and vocal nodules, the acoustic measure tended to differentiate normal voices and voices with nodules in children and adults, and some displayed significant correlations with the perceptual attributes of overall severity of dysphonia, roughness, and/or breathiness. None of the acoustic measures correlated significantly with the perceptual attribute of strain. Limitations in the strength of the correlations between acoustic measures and perceptual attributes were attributed to factors that can be addressed in future investigations, which can now utilize the algorithms that were developed in this investigation for children's voices. Preliminary recommendations are made for the clinical assessment of pediatric voice disorders.by Asako Masaki.Ph.D

Models and Analysis of Vocal Emissions for Biomedical Applications

The International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications (MAVEBA) came into being in 1999 from the particularly felt need of sharing know-how, objectives and results between areas that until then seemed quite distinct such as bioengineering, medicine and singing. MAVEBA deals with all aspects concerning the study of the human voice with applications ranging from the newborn to the adult and elderly. Over the years the initial issues have grown and spread also in other fields of research such as occupational voice disorders, neurology, rehabilitation, image and video analysis. MAVEBA takes place every two years in Firenze, Italy. This edition celebrates twenty-two years of uninterrupted and successful research in the field of voice analysis

VOice analysis with Iphones: a low Cost Experimental Solution

Background: Acoustic voice analysis requires a resource intensive setup, including a soundproof booth. This project evaluates smartphone microphone and recording environment impacts on voice sample collection for acoustic voice analysis. A proprietary analysis algorithm is presented for validation. Methods: Microphone and recording environment were evaluated using previously collected voice samples presented in four conditions to test two microphones and two recording environments. Prospective samples were used to test the proprietary algorithm, whereby samples were analyzed using this and Praat. Results: Microphone and recording environment had small, clinically unimportant impacts on most measurements. The proprietary algorithm reliably analyzed sustained vowels, with strong correlation to the Praat results. Continuous speech analysis was less reliable. Conclusion: Smartphone microphones are adequate for voice sample collection. Quiet, non-soundproof settings can be used for voice collection. The proprietary algorithm represents a reliable method to analyze sustained vowel samples. Some improvements are necessary before continuous speech analysis can be considered valid

Does the Acoustic Voice Quality Index (AVQI) correlate with perceived creak and strain in normophonic young adult Finnish females?

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