Aerodynamic measures of glottal function: what extra can they tell us and how do they guide management?

Laryngeal Aerodynamics, Acoustics, and Hypernasality in Children With Cleft Palate

OBJECTIVE

The objective of this study was to examine the relationship between laryngeal aerodynamics, acoustics, and hypernasality in children with cleft palate with or without lip (CP ± L).

METHOD

This study used a prospectively performed cross-sectional design. Fifty-six children between the ages of 6 and 17 years with CP ± L participated (Mage= 11.7, SD = 3.4; male = 32, female = 24). Children were separated into four groups based on auditory-perceptual ratings of hypernasality made using the Cleft Audit Protocol for Speech-Augmented-Americleft Modification protocol. Laryngeal aerodynamic measures including subglottal pressure, transglottal airflow, laryngeal aerodynamic resistance (LAR), and phonation threshold pressure were collected. Acoustic measures of smoothed cepstral peak prominence (CPP) and low-to-high ratio on sustained vowels and connected speech were also considered. Analyses controlled for age, sex, auditory-perceptual ratings of voice quality, and speech intelligibility.

RESULTS

Children with minimally or mildly hypernasal resonance demonstrated significantly increased subglottal pressure, reduced transglottal airflow, and increased LAR, when compared with children with balanced or moderately hypernasal resonance. CPP on sustained vowel was significantly lower for children with moderate hypernasality when compared with all other groups-suggesting poorer voice quality. Other acoustic measures were in or near normative pediatric range.

CONCLUSIONS

Children with CP ± L and minimal or mildly hypernasal resonance demonstrated aerodynamic voice measures indicative of vocal hyperfunction. These findings suggest that children with CP ± L may compensate for velopharyngeal dysfunction on a laryngeal level, thus increasing the risk of laryngeal pathology. Future study should explore the relationship between laryngeal function and velopharyngeal port closure and consider how voice problems can be prevented or mitigated in children with CP ± L.

Effects of Increasing Vocal Tract Insertion Depth in Semi-Occluded Vocal Tract Exercises on an Excised Canine Model

INTRODUCTION

Straw phonation therapy, a form of semi-occluded vocal tract (SOVT) exercise, is commonly used to help treat various voice disorders. Although straw phonation therapy has been studied extensively for decades, the impact of straw depth on vocal function remains unexplored. This study aims to quantify the effects of various straw vocal tract insertion depths (VTID) into the vocal tract on common aerodynamic parameters such as phonation threshold pressure (PTP), phonation threshold flow (PTF), and phonation threshold power (PTW) in an ex vivo canine model. It was hypothesized that increasing the VTID of the straw would reduce the PTP, PTF, and PTW.

METHODS

Five excised canine larynges were mounted on a pseudolung apparatus and attached to a simulated vocal tract in an acoustic sound booth. Two straw depths (20.0 and 60.0 mm) were tested to determine the effect of VTID on ease of phonation as indicated by the aerodynamic parameters of PTP, PTF, and PTW. The control had no straw and a VTID of 0.0 mm. The straw diameter and length above the simulated vocal tract were consistent between the straws. Sustained phonation was achieved, and aerodynamic data was collected and analyzed.

RESULTS

Both straw treatment groups exhibited significant reductions in PTP and PTW compared to the control. However, there were no significant differences between the 20.0 or 60.0 mm straw depths in PTP, PTF, or PTW.

CONCLUSION

The presence of a straw significantly reduced PTP and PTW, but VTID did not appear to influence these outcomes. This supports previous straw phonation therapy research suggesting that straw phonation therapy is beneficial primarily due to the presence of the straw rather than the depth of insertion. Future studies should explore the combined effects of varying straw diameters, lengths, and depths to optimize SOVT therapy for clinical use.

Aerodynamic Threshold Measures for Reflecting Glottal Closure in Voice Disorders

PURPOSE

Previous work suggested that phonation threshold pressure (PTP), phonation threshold flow (PTF), and phonation threshold power (PTW) could be effective aerodynamic measures for quantifying glottal incompetence. This study examined how these measures could reflect varying extent of incomplete glottal closure in individuals with voice disorders.

METHOD

Thirty individuals formally diagnosed with glottal incompetence, including 10 with hypofunctional disorders (hypo group) and 20 with hyperfunctional disorders (hyper group), and 30 individuals with normal voice (control group) participated in the study. PTP was measured indirectly by intra-oral pressure during production of bilabial stop consonant-vowel syllables, PTF was measured during the sustained vowel /a/, and PTW was obtained as the product of PTP and PTF. The extent of incomplete glottal closure was quantified by normalized glottal gap (NGG) and normalized glottal gap area (NGGA) based on image analysis of videostroboscopic recordings of sustained /i/.

RESULTS

Significant differences in all threshold measures (p < .05) were found among three participant groups with medium-to-large effect sizes (ηp2 = .128-.220), with significantly higher values for the hypo group than the control group and no significant differences between the hyper and control groups. Receiver operating characteristic (ROC) analysis showed the highest diagnostic or classification accuracy contrasting between the hypo and control groups (area under the ROC curve = .717-.757), with the highest classification accuracy for PTW. There were significant, moderate-to-strong positive correlations with NGG and NGGA for the disorders group (Pearson's r = .4244-.6226) and the hypo group (r = .5689-.8949).

CONCLUSIONS

These measures could be effective for identifying glottal incompetence, especially for hypofunctional disorders. PTW could be more sensitive than PTP and PTF in reflecting the extent of incomplete glottal closure, consistent with theoretical predictions. Their relative sensitivities for quantifying distinct incomplete glottal closures specific to different voice disorders should be evaluated in future studies.

Identification and analysis of Nonlinear behaviors of vocal fold biomechanics during phonation to assess efficacy of surgery for benign laryngeal Diseases

BACKGROUND

Current voice assessments focus on perceptive evaluation and acoustic analysis. The interaction of vocal tract pressure (PVT) and vocal fold (VF) vibrations are important for volume and pitch control. However, there are currently little non-invasive ways to measure PVT. Limited information has been provided by previous human trials, and interactions between PVT and VF vibrations and the potential clinical application remain unclear. Here, we propose a non-invasive method for monitoring the nonlinear characteristics of PVT and VF vibrations, analyze voices from pathological and healthy individuals, and evaluate treatment efficacy.

METHOD

Healthy volunteers and patients with benign laryngeal lesions were recruited for this study. PVT was estimated using an airflow interruption method, VF vibrational frequency was calculated from accelerometer signals, and nonlinear relationships between PVT and VF vibrations were analyzed. Results from healthy volunteers and patients, as well as pre- and post-operation for the patients, were compared.

RESULTS

For healthy volunteers, nonlinearity was exhibited as an initial increase and then prompt decrease in vibrational frequency at the end of phonation, coinciding with PVT equilibrating with the subglottal pressure upon airflow interruption. For patients, nonlinearity was present throughout the phonation period pre-operatively, but showed a similar trend to healthy volunteers post-operatively.

CONCLUSION

This novel method simultaneously monitors PVT and VF vibration and helps clarify the role of PVT. The results demonstrate differences in nonlinear characteristics between healthy volunteers and patients, and pre-/post-operation in patients. The method may serve as an analysis tool for clinicians to assess pathological phonation and treatment efficacy.

Examining Relationships Between GRBAS Ratings and Acoustic, Aerodynamic and Patient-Reported Voice Measures in Adults With Voice Disorders

OBJECTIVE

To determine if auditory-perceptual voice ratings performed using the GRBAS scale correlate with acoustic and aerodynamic measures of voice. A secondary aim was to examine the relationship between GRBAS ratings and patient-reported quality of life scales.

METHODS

GRBAS ratings, acoustic, aerodynamic and patient-reported quality of life ratings were collected from the University of Wisconsin Madison Voice and Swallow Outcomes Database for 508 adults with voice disorders. Acoustic measures included noise to harmonic ratio, jitter%, shimmer%, highest fundamental frequency (F0) of vocal range, lowest F0 of vocal range, maximum phonation time and dysphonia severity index. Aerodynamic measures included phonation threshold pressure, subglottal pressure, mean transglottal airflow and laryngeal airway resistance. Patient-reported quality of life measures included the Vocal Handicap Index (VHI) and Glottal Function Index (GFI).

RESULTS

GRBAS ratings were significantly correlated with several acoustic and aerodynamic measures, VHI and GFI. The strongest significant correlations for acoustic measures were observed between GRBAS ratings of overall voice quality and perturbation measures (jitter% r = 0.58, shimmer% r = 0.45, noise to harmonic ratio r = 0.36, Dysphonia Severity Index r = -0.56). The strongest significant correlation for aerodynamic voice measures was observed between GRBAS ratings of breathiness and transglottal airflow (r = 0.23), subglottal pressure (r = 0.49), and phonation threshold pressure (r = 0.26). GRBAS ratings were also significantly correlated with both VHI and the GFI scales. R values were higher for the VHI, but remained largely in low range for both scales.

CONCLUSIONS

Although GRBAS ratings were significantly correlated with multiple objective voice and patient related quality of life ratings, r values were low. These findings support the need for multiple voice measures when performing voice evaluations as no single voice measure was highly correlated with voice quality as measured by the GRBAS scale.

Parkinsonics: A Randomized, Blinded, Cross-Over Trial of Group Singing for Motor and Nonmotor Symptoms in Idiopathic Parkinson Disease

Introduction

Parkinson's disease (PD) frequently causes communication difficulties due to various voice impairments and there are few treatment options for vocal/communication complaints. We assessed the effects of weekly group singing on PD patients' objective vocal and motoric function, cognition, mood, self-efficacy, and quality of life.

Methods

Thirty-two participants were randomly assigned to either a singing group or a facilitated discussion group weekly over 12 weeks. After 12 weeks, participants crossed over for an additional 12 weeks. Evaluations were performed at baseline and every six weeks for 30 weeks. Objective voice measures included volume/loudness (decibels), held vowel duration, jitter, shimmer, and harmonic-to-noise ratio. Additional outcome measures included patient-centered quality of life, voice-related quality of life, MDS-UPDRS, Montreal Cognitive Assessment, and questionnaires assessing depression, self-efficacy, and overall well-being.

Results

Twenty-six participants (16 M/10F; Hoehn & Yahr stage 2.3 (range 2-3); and age 68.6 (55-89)) completed the study. Across participants in both groups (intention-to-treat analyses), there was significant improvement from baseline in average loudness on the Cookie Theft picture description at 24 weeks (end of interventions), corresponding with improved minimal reading volumes at 24 weeks and 30 weeks (end of study). Similarly, there were improvements in minimal loudness on Rainbow passage reading at 24 and 30 weeks. There were improvements observed in the Emotional Well-Being (mean delta -12.7 points, p = 0.037) and Body Discomfort (mean delta -18.6 points, p = 0.001) domains of the PDQ-39 from baseline to week 24 in the overall cohort and greater improvement in the Communication domain for Group S than Group D after 12 weeks of singing (delta -12.9 points, p = 0.016). Baseline differences between the participant groups (age, gender, Hoehn & Yahr stage, and several voice loudness measures) and observed improvements during the weekly discussion group period limited our ability to attribute all of the above results specifically to singing (per-protocol analyses). No significant changes in other assessed outcome measures were found.

Conclusions

Weekly group singing may improve some aspects of conversational voice volume and quality of life in PD. Some improvements were sustained at least six weeks after interventions ended. Further investigations of the mechanism of benefit and randomized controlled studies (without crossover) to assess the longitudinal effects of singing in PD are necessary.

Multidimensional voice assessment: the immediate effects of Lax Vox® in singers with voice complaints

ABSTRACT Purpose: to multidimensionally assess the effect of the Lax Vox® vocal technique on singers with voice complaints. Methods: a comparative intrasubject study that assessed 30 singers - 13 males and 17 females, aged 18 to 55 years - who self-reported voice complaints and had voice problems symptoms. The participants were submitted to voice assessment with perceptive-auditory, acoustic, aerodynamic, and electroglottographic voice analysis, as well as laryngeal assessment with high-speed videolaryngoscopy. The participants were assessed at two moments: 1) at the beginning of the data collection; and 2) five minutes after performing the Lax Vox® vocal technique. The groups were compared with appropriate statistical tests, with a 5% significance level. Results: in the acoustic analysis, there was an increase in the fundamental frequency for males, after using the Lax Vox® vocal technique. In the aerodynamic assessment, there was an increase in the airflow mean values during vocalization, as well as in aerodynamic power after using the Lax Vox® vocal technique in both groups. Conclusion: the Lax Vox® vocal technique, in the studied singers with a complaint of dysphonia, promoted an increase in the fundamental frequency, for males. In the aerodynamic parameters, in both sexes, it promoted an increase in the airflow and aerodynamic power.

The physical significance of acoustic parameters and its clinical significance of dysarthria in Parkinson's disease

Dysarthria is universal in Parkinson's disease (PD) during disease progression; however, the quality of vocalization changes is often ignored. Furthermore, the role of changes in the acoustic parameters of phonation in PD patients remains unclear. We recruited 35 PD patients and 26 healthy controls to perform single, double, and multiple syllable tests. A logistic regression was performed to differentiate between protective and risk factors among the acoustic parameters. The results indicated that the mean f0, max f0, min f0, jitter, duration of speech and median intensity of speaking for the PD patients were significantly different from those of the healthy controls. These results reveal some promising indicators of dysarthric symptoms consisting of acoustic parameters, and they strengthen our understanding about the significance of changes in phonation by PD patients, which may accelerate the discovery of novel PD biomarkers.

Acoustic and Aerodynamic Analyses of the Voice of Prelingually Deaf Young Men After Cochlear Implantation

OBJECTIVE

The purpose of this study was to characterize the acoustic and aerodynamics of the voice of young men with prelingual deafness after cochlear implantation (CI) to provide a theoretical basis for their rehabilitation after CI.

METHODS

The CI group included 17 young men with prelingual deafness who implanted cochlear at 18-24 years old. The control group included 17 normally hearing young men at the same age. The 10-item Voice Handicap Index, acoustic parameters, and aerodynamic parameters were evaluated.

RESULTS

For the acoustic parameters, the F0, SDF0, and Jitter of the CI group were higher than those of the Control group, and these differences were statistically significant. Additionally, The difference in mean shimmer and mean NHR values between the CI group and the Control group was not statistically significant For the aerodynamic parameters, the subglottal pressure and aerodynamic power of the CI group were significantly higher than those of the Control group, whereas the MPT was significantly shorter.

DISCUSSION

Due to excessive stress on the laryngeal muscle and limited pneumo-phono-articulatory coordination, the young men in the CI group had a thin voice and poor voice control and muscle coordination, and they exhibited excessive laryngeal resistance. We propose that after CI, in addition to regular hearing and speech rehabilitation, voice training is also extremely important for prelingually deaf young men.

Medidas acústicas e aerodinâmicas em cantores: comparação entre homens e mulheres

RESUMO Objetivo Comparar medidas acústicas e aerodinâmicas da voz em homens e mulheres cantores. Método Trata-se de um estudo transversal, observacional, comparativo, com amostra de conveniência. Participaram do estudo 30 homens e 30 mulheres cantores. Foi realizada avaliação das medidas acústicas (intensidade e frequência fundamental) e aerodinâmicas (tempo de expiração, pressão aérea, fluxo de ar expirado e vozeado, volume expiratório, potência e resistência aerodinâmica, impedância acústica e eficiência aerodinâmica) durante a emissão da sílaba /pá/ em frequência e intensidade habituais, sete vezes consecutivas. Estas emissões permitem a extração de medidas de pressão aérea (obtidas da consoante plosiva /p/ que estima a pressão glótica) e das medidas de fluxo aéreo e acústicas da voz (obtidas da vogal /a/ da sílaba /pá/). Resultados Na comparação de homens e mulheres cantores, as mulheres apresentam maiores valores de frequência fundamental, e não houve diferenças na avaliação de valores das medidas aerodinâmicas entre os gêneros. Conclusão Os valores das medidas aerodinâmicas não se diferenciam entre mulheres e homens cantores.

Development of Excised Larynx

The larynx is a complex organ which has a role in a variety of functions such as phonation, breathing, and swallowing. To research these functions, it is widely accepted that in vivo studies provide more anatomically and physiologically relevant findings. However, invasive procedures are generally needed to measure variables such a subglottal pressure, vocal fold tension and stiffness, and cricothyroid muscle stretch. Performing studies using excised larynges is a useful technique which makes it possible to not only measure phonation parameters but control them as well. Early studies using excised larynges mainly focused on controlling specific parameters and mathematical modeling simulations. The use of these studies has helped further research in laryngeal anatomy, imaging techniques, as well as aerodynamic, acoustic, and biomechanical properties. Here, we describe the progress of this research over the past 5 years. The number of accepted animal models has increased and ideas from excised larynx studies are starting to be applied to treatment methods for laryngeal disorders. These experiments are only valid for an excised situation and must continue to be combined with animal experimentation and clinical observations.

The Utility of Pulmonary Function Testing in Patients Presenting With Dysphonia

OBJECTIVE

We aimed to evaluate the utility of pulmonary function testing (PFT), particularly forced expiratory flow (FEF) 25-75%, in patients presenting with dysphonia.

STUDY DESIGN

A retrospective chart review was carried out.

METHODS

Records of 199 patients who presented with dysphonia were reviewed to determine whether in-office PFTs, which we perform routinely, lead to new pulmonary diagnoses or the need for additional pulmonary medications, after assessment by a pulmonologist. Of particular interest was evaluating if FEF25-75% of predicted values less than 80% can be used as a marker for occult pulmonary disease in patients presenting with dysphonia.

RESULTS

Of the 199 patient charts reviewed, 129 were female and 70 were male. The age of patients ranged from 18 to 88 years, with a mean of 46.8 years. The body mass index ranged from 17.5 to 53.4 kg/m². One hundred five (52.8%) patients had FEF25-75% values less than 80% of predicted (poor midflow values). Of these patients, 76 (72.4%) were referred to a pulmonologist, 22 of 76 (28.9%) completed the referral, and 17 of 22 (77.3%) received a new pulmonary diagnosis or change in medications. Of the 155 patients without a history of pulmonary disease, 76 had poor midflow values, 57 (75%) of these patients were referred, and 12 of 57 (21%) completed the referral. Eight (67%) of these 12 patients were diagnosed with a previously unrecognized pulmonary disorder. Of the 44 patients with a prior history of pulmonary disease, 29 (65.9%) had poor midflow values. Nineteen (65.5%) of these patients were referred, and 9 (47%) received a new pulmonary diagnosis or a change in their medications. There were 51 classically trained singers and 148 nonclassically trained singers or nonsingers. There was no significant difference in average midflow values between the two groups (80.96 ± 24.7 and 80.73 ± 28.4, respectively) or in the percentage of classically trained singers with poor midflow values compared with nonsingers (53.5% vs. 49%, respectively).

CONCLUSION

This study suggests that patients with dysphonia may have unrecognized underlying pulmonary disease, and PFT should be considered as part of the routine initial voice evaluation for patients presenting with dysphonia.

A feasibility study on non-invasive oxidative metabolism detection and acoustic assessment of human vocal cords by using optical technique

Voice disorder such as vocal fatigue is a common and complex multifaceted clinical problem that presents a significant impact on quality of life. In this study, the functional near-infrared diffuse optical technique (fNIRS-DOT) was proposed as a novel approach for human vocal cords oxidative metabolism detection and acoustic assessment simultaneously to provide a multidimensional assessment of voice disorder. A totally of 60 healthy subjects included 30 male and 30 female adults of age-matched were recruited and performed a vocal loading task to trigger a mild inflammation of the vocal cords in this study. In the results of oxidative metabolism, the vocal cords expressed hypoxia after vocal loading task in both male and female groups that could provide relevant information on the relationship between tissue oxygen consumption and supply for vocal cords diagnosis. Additionally, the results of optical acoustic assessment revealed the worse/changes voice quality after vocal loading task. Therefore, integration of non-invasive oxidative metabolism detection and acoustic assessment by using optical technique could provide more relevant information for diagnosis of voice disorders. The multi-functional vocal cords detection system could provide a good feasibility for clinical applications such as diagnosis and therapeutic monitoring of voice disorder.