Respiratory and laryngeal function during spontaneous speaking in teachers with voice disorders

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.

Impact of Pulmonary Function on Voice Outcomes After Injection Laryngoplasty for Unilateral Vocal Fold Paralysis

OBJECTIVES

Pulmonary function is closely associated with voice quality especially in patients with voice disorder including unilateral vocal fold paralysis (UVFP). Injection laryngoplasty (IL) is the standard treatment for patients with UVFP. We investigated the subjective and objective voice outcomes according to pulmonary function test (PFT) before IL in patients with UVFP.

METHOD

We retrospectively analyzed the patients who underwent IL for UVFP between 2004 and 2021 (N = 1201), and finally investigated 261 patients with PFT results before IL. The patients were classified into three groups according to results of PFT: normal (n = 189, 72%), mild (n = 40, 15%), and moderate (n = 32, 13%) obstructive pattern. Aspiration symptoms and subjective and objective voice parameters of voice handicap index (VHI), GRBAS score, maximal phonation time (MPT), Jitter, Shimmer, and noise to harmonic ratio (NHR) were compared between normal and abnormal (mild or moderate obstructive pattern) PFT groups.

RESULTS

Age (68.0 ± 9.1 and 61.2 ± 12.6, respectively) was significantly higher and males were more common (84.7% and 57.7%, respectively) in abnormal PFT than in normal PFT. Aspiration showed significant improvement in all groups. The subjective and objective voice parameters significantly improved after IL in normal and mild obstruction groups, but MPT, Shimmer, and VHI did not significantly improve in the moderate obstruction group. The improvement in VHI-30 after IL was significantly higher in the normal group (20.0 ± 29.5) than in the mild (10.3 ± 32.8) or moderate (9.9 ± 33.2) obstruction group (P = 0.035). Improved amounts of MPT, Jitter, Shimmer, and NHR were not significantly different among the groups, but improvement of VHI was smallest in the moderate obstructive pattern group.

CONCLUSION

Voice parameters showed significant improvement after IL in both normal and mild obstructive pattern groups, but MPT and VHI did not significantly improve in the moderate obstructive pattern group. In addition, patients with normal pulmonary function had marked improvement of subjective symptoms after IL in comparison with patients with abnormal pulmonary function.

Use of a Vortex Whistle for Measures of Respiratory Capacity

OBJECTIVES

A vortex whistle produces a tone which has a frequency proportional to the inlet air flow rate. The objectives of this study were to replicate previous studies demonstrating the use of a vortex whistle as an accurate flow meter, and to assess the degree of relationship between measures of vital capacity (VC) obtained using low-cost methods (vortex whistle and hand-held spirometry) vs. pneumotach-based spirometry.

METHODOLOGY

A vortex whistle was designed using 3D modeling software and manufactured using a 3D printer with non-toxic, biodegradable polylactic acid (PLA). The digitized vortex whistle tone was analyzed using custom software to produce a frequency vs. time contour. As the frequency is proportional to flow, the integral of this curve corresponds to the overall volume by a linear relationship. The accuracy of vortex whistle volume estimates were assessed using (1) controlled flow rates from a consistent volume calibration syringe, and (2) with 66 subjects between the ages of 18-30 yrs. in comparison to hand-held spirometry and two pneumotach systems.

RESULTS

Observations from the calibration syringe experiment confirmed that the vortex whistle and software are able to effectively track the flow rate, with a correlation coefficient between the average flow and the average frequency of r² = 0.9965. Results from the human VC testing showed that measures obtained using both vortex whistles and hand-held spirometry correlated very strongly (r > 0.94) with computerized pneumotach systems, and the strength of correlations obtained via vortex whistles vs. hand-held spirometry were highly comparable.

DISCUSSION & CONCLUSIONS

When coupled with the analysis software described herein, valid and reliable frequency/flow curves and volume estimates may be obtained using a vortex whistle that are highly comparable to the hand-held spirometer. The use of the vortex whistle has the potential to bring measures of basic respiratory function to clinicians and patients alike at a fraction of the cost of currently used spirometric methods.

Enhancing the Vortex Whistle for Measures of Respiratory Capacity via CFD and CAA

A vortex whistle produces a fundamental frequency proportional to the inlet flow rate. Recent investigations using vortex whistles have focused on the use of this relationship to quantify aspects of respiratory function. Despite promising results, there is a lack of understanding of the physical mechanisms underlying vortex whistle function. This paper begins with a principled study of the aero-acoustic properties of the vortex whistle. First a high-fidelity computation fluid dynamics (CFD) simulation was developed to predict the unsteady flow field induced by the vortex whistle when the expiratory flow is applied. A computational aero-acoustic analysis (CAA) was applied to predict the acoustic response of the vortex whistle and to capture the frequency and level of the signature spectral peaks. The CFD is validated against prior experimental data on the vortex whistle. The CFD was used to: (a) determine the source of the vortex whistle harmonics; and (b) investigate the effect of an outlet tube terminator, proposed by Awan and Awan (2020). The CFD and CAA indicated that the harmonics are generated by the cylindrical cavity of the vortex whistle, and the outlet terminator increases harmonic signal-to-noise ratio by increasing the pressure fluctuation within the cylindrical cavity. These results support the addition of the outlet tube terminator and provide insight into future design modifications, that will enhance the reliability of the vortex whistle analyses and enable additional measures of respiratory capacity.

The effects of vocal exertion on lung volume measurements and acoustics in speakers reporting high and low vocal fatigue

Purpose

Vocal exertion is common and often results in reduced respiratory and laryngeal efficiency. It is unknown, however, whether the respiratory kinematic and acoustic adjustments employed during vocal exertion differ between speakers reporting vocal fatigue and those who do not. This study compared respiratory kinematics and acoustic measures in individuals reporting low and high levels of vocal fatigue during a vocal exertion task.

Methods

Individuals reporting low (N = 20) and high (N = 10) vocal fatigue participated in a repeated measures design study over 2 days. On each day, participants completed a 10-minute vocal exertion task consisting of repeated, loud vowel productions at elevated F0 sustained for maximum phonation time. Respiratory kinematic and acoustic measures were analyzed on the 1^st vowel production (T0), and the vowels produced 2 minutes (T2), 5 minutes (T5), 7 minutes (T7), and 10 minutes (T10) into the vocal exertion task. Vowel durations were also measured at each time point.

Results

No differences in respiratory kinematics were observed between low and high vocal fatigue groups at T0. As the vocal exertion task progressed (T2-T10), individuals reporting high vocal fatigue initiated phonation at lower lung volumes while individuals with low vocal fatigue initiated phonation at higher lung volumes. As the exertion task progressed, total lung volume excursion decreased in both groups. Differences in acoustic measures were observed, as individuals reporting high vocal fatigue produced softer, shorter vowels from T0 through T10.

Conclusions

Individuals reporting high vocal fatigue employed less efficient respiratory strategies during periods of increased vocal demand when compared with individuals reporting low vocal fatigue. Individuals reporting high vocal fatigue had shorter maximum phonation time on loud vowels. Further study should examine the potential screening value of loud maximum phonation time, as well as the clinical implications of the observed respiratory patterns for managing vocal fatigue.

Integrative Review and Framework of Suggested Mechanisms in Primary Muscle Tension Dysphonia

PURPOSE

Despite the high prevalence of primary muscle tension dysphonia (MTD-1), its underlying mechanisms and their interrelationships have yet to be fully identified. The objectives of this integrative review were (a) to describe and classify the suggested underlying mechanisms for MTD-1, (b) to appraise the empirical evidence supporting each of the proposed mechanisms, and (c) to summarize the information in an integrative model.

METHOD

PubMed, Scopus, and CINAHL were searched for all publications pertaining to muscle tension dysphonia. Papers were retained if they included theoretical or empirical data pertaining to underlying mechanisms of MTD-1. A total of 921 papers initially qualified for screening, of which 100 remained for consideration in this review. Underlying mechanisms of MTD-1 were extracted using a consensus approach.

RESULTS

Seven broad categories of putative mechanisms involved in MTD-1 were identified: psychosocial, autonomic, sensorimotor, respiratory, postural, inflammatory, and neuromuscular. These categories were further divided into 19 subcategories detailed in the body of this review article. Based on the reviewed evidence, our proposed integrative model presents MTD-1 as an idiosyncratic motor adaptation to physiological perturbation or perceived threat. Under this model, physiologically or psychologically aversive stimuli can instigate a series of motor adaptations at multiple levels of the nervous system, ultimately disturbing muscle activation patterns and their biomechanical outcomes. Importantly, these adaptations appear to have the potential to become chronic even after threatening stimuli are withdrawn.

CONCLUSIONS

The proposed model highlights the importance of personalized rehabilitation in MTD-1 treatment. Limitations of the literature are discussed to provide guidance for future research aimed at improving our understanding of MTD-1.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19586065.

Impact of Vocal Effort on Respiratory and Articulatory Kinematics

PURPOSE

The goal of this study was to examine the effects of increases in vocal effort, without changing speech intensity, on respiratory and articulatory kinematics in young adults with typical voices.

METHOD

A total of 10 participants completed a reading task under three speaking conditions: baseline, mild vocal effort, and maximum vocal effort. Respiratory inductance plethysmography bands around the chest and abdomen were used to estimate lung volumes during speech, and sensor coils for electromagnetic articulography were used to transduce articulatory movements, resulting in the following outcome measures: lung volume at speech initiation (LVSI) and at speech termination (LVST), articulatory kinematic vowel space (AKVS) of two points on the tongue dorsum (body and blade), and lip aperture.

RESULTS

With increases in vocal effort, and no statistical changes in speech intensity, speakers showed: (a) no statistically significant differences in LVST, (b) statistically significant increases in LVSI, (c) no statistically significant differences in AKVS measures, and (d) statistically significant reductions in lip aperture.

CONCLUSIONS

Speakers with typical voices exhibited larger lung volumes at speech initiation during increases in vocal effort, paired with reduced lip displacements. To our knowledge, this is the first study to demonstrate evidence that articulatory kinematics are impacted by modulations in vocal effort. However, the mechanisms underlying vocal effort may differ between speakers with and without voice disorders. Thus, future work should examine the relationship between articulatory kinematics, respiratory kinematics, and laryngeal-level changes during vocal effort in speakers with and without voice disorders.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.17065457.

Vocal Acoustics and Aerodynamics During Scripted Reading Compared to Spontaneous Speech

BACKGROUND

Examination of vocal acoustics and phonatory aerodynamics during connected speech provide a more ecologically valid approach to voice assessment than single phoneme measures. The purpose of the current investigation was to determine if differences exist in vocal acoustics and aerodynamics between reading and spontaneous speech tasks in patients with common voice disorders.

METHODS

The Emory University Institutional Review Board approved this retrospective study. The voice records of 100 patients (74 females and 26 males) diagnosed with benign voice disorders and referred for voice evaluation at the Emory Voice Center between November 2018 and March 2019 were analyzed. These consisted of reading a scripted passage (the Rainbow Passage) and spontaneous speech (describing how to make a peanut butter and jelly sandwich). Data collected included gender, voice diagnosis, mean fundamental frequency (F₀), mean airflow during voicing, and mean inspiratory airflow (MIA).

RESULTS

Univariate analysis assessed normality of the data. Variables with normal distribution utilized paired t test. Non-normal data were log transformed. Mean F₀ was not significant for complete case analysis (P = 0.053) but gender based stratified analysis, for females (mean difference = 4.68 Hz; 95% CI = 0.359, 9.0012; P = 0.03). Gender-related statistical differences were also found in MIA in women (P = 0.0001), and P = 0.0003 for MIA in men. The direction and range of change between scripted reading and the spontaneous speech tasks in all metrics varied widely. No consistent patterns were noted in gender, age and diagnosis across the parameters studied. However, clinically salient findings in the range of MIA were noted in a small subgroup of participants.

CONCLUSIONS

This study suggests that multiple testing stimuli for phonatory aerodynamic and acoustic outcomes measurement may be appropriate for use depending on the need and vocal challenges of the individual patient. Clinically, both structured reading and spontaneous speech provide valuable insight into the vocal capabilities of the patient.

Computational simulations of respiratory-laryngeal interactions and their effects on lung volume termination during phonation: Considerations for hyperfunctional voice disorders

Glottal resistance plays an important role in airflow conservation, especially in the context of high vocal demands. However, it remains unclear if laryngeal strategies most effective in controlling airflow during phonation are consistent with clinical manifestations of vocal hyperfunction. This study used a previously validated three-dimensional computational model of the vocal folds coupled with a respiratory model to investigate which laryngeal strategies were the best predictors of lung volume termination (LVT) and how these strategies' effects were modulated by respiratory parameters. Results indicated that the initial glottal angle and vertical thickness of the vocal folds were the best predictors of LVT regardless of subglottal pressure, lung volume initiation, and breath group duration. The effect of vertical thickness on LVT increased with the subglottal pressure-highlighting the importance of monitoring loudness during voice therapy to avoid laryngeal compensation-and decreased with increasing vocal fold stiffness. A positive initial glottal angle required an increase in vertical thickness to complete a target utterance, especially when the respiratory system was taxed. Overall, findings support the hypothesis that laryngeal strategies consistent with hyperfunctional voice disorders are effective in increasing LVT, and that conservation of airflow and respiratory effort may represent underlying mechanisms in those disorders.

Clinical Features of Essential Voice Tremor and Associations with Tremor Severity and Response to Octanoic Acid Treatment

OBJECTIVES/HYPOTHESIS

The purpose of this study was to characterize the clinical features, tremor variability, and factors related to octanoic acid (OA) treatment response in essential voice tremor (EVT).

STUDY DESIGN

Prospective, double blind, placebo-controlled, crossover study with secondary analysis.

METHODS

Clinical tremor features in 16 individuals with EVT were comprehensively assessed, and correlations with acoustic tremor severity were determined. Intrasubject and intersubject variability measures were analyzed from 18 repeated measures for each acoustic tremor variable. Clinical correlates of treatment response were evaluated, and cumulative effects over a 2-week period of OA drug dosing were assessed.

RESULTS

Participants with EVT were 90% female with a mean age of 70.31 (±8.68) years at the time of testing. Neurologist-rated body tremor beyond the vocal tract region was present in 69% of participants, and multiple vocal tract regions contributed to the voice tremor. The mean frequency of amplitude tremor was 4.67 Hz (±0.88). Respiratory tremor was evident in 50% of participants. Participants experienced moderate voice-related disability as assessed on the Voice Handicap Index-10 (19.38, ±8.50), and increased speaking effort. Acoustic tremor severity was significantly associated with severity of tremor affecting vocal tract structures. Overall intrasubject consistency was strong (single measures intraclass correlation coefficient = 0.701, P < .01), with high intersubject variability. Acoustic tremor severity was significantly, positively associated with treatment response, and results suggested a cumulative OA benefit for magnitude of amplitude tremor.

CONCLUSIONS

This study identified common clinical correlates of EVT and demonstrated positive associations between acoustic tremor severity, severity of affected vocal tract structures, and response to treatment.

LEVEL OF EVIDENCE

2 Laryngoscope, 2021.

Neuromuscular and biomechanical adjustments of the speech mechanism during modulation of vocal loudness in children with cerebral palsy and dysarthria

ABSTRACChildren with cerebral palsy (CP) are characterized as difficult to understand because of poor articulation and breathy voice quality. This case series describes the subsystems of the speech mechanism (i.e., respiratory, laryngeal, oroarticulatory) in four children with CP and four matched typically developing children (TDC) during the modulation of vocal loudness. TDC used biomechanically efficient strategies among speech subsystems to increase vocal loudness. Children with CP made fewer breathing adjustments but recruited greater chest wall muscle activity and neuromuscular drive for louder productions. These results inform future clinical research and identify speech treatment targets for children with motor speech disorders.

[Physiotherapy treatment of vegetative disorders in patients with voice disorders]

OBJECTIVE

To increase the effectiveness of treatment of hypotonic functional dysphonia using physiotherapy in patients with neurovegetative disorders.

MATERIAL AND METHODS

The study included 42 patients, aged from 25 to 64 years, with disturbed vocal function, which included anamnestic analysis, an objective study of ENT organs by conventional methods, a video stroboscopy of the larynx, a cytological study of smears from the laryngeal mucosa, and the determination of the functional state of the autonomic nervous system (ANS).

RESULTS

The clinical-physiological study of VNS shows neurovegetative dysfunction (inadequate autonomic support of activity) in 10 patients. In these patients, the traditional conservative treatment was ineffective. Acupuncture used for treatment of neurovegetative disorders in these patients significantly improves the results of traditional treatment.

CONCLUSION

The results indicate an increase in the effectiveness of physiotherapy treatment (reflexotherapy using magnetic-infrared laser radiation and acupuncture) of ANS condition. These measures can be carried out in conjunction with traditional methods of treatment or in the case of their low efficiency.

Isolated and Combined Respiratory Training for Muscle Tension Dysphonia: Preliminary Findings

PURPOSE

The purpose of this study was to determine the feasibility of altering speech breathing patterns and dysphonia severity through training increased levels of lung volume use during speech. It was hypothesized that respiratory-based training would increase lung volume levels during speech as well as improve acoustic voice measures, and that the addition of laryngeal-based treatment would further improve voice acoustics by treatment completion.

METHOD

A multiple baseline, single subject design was replicated over six participants with primary muscle tension dysphonia as a preliminary investigation of novel respiratory treatment methods. Following four baseline probes (1-4), two phases of treatment were implemented over 6 weeks. Respiratory lung volume-based training (RLVT) and subsequent performance was probed at sessions 5 to 7 and laryngeal-based training was added to the RLVT and probed at sessions 8 to 10. Visual biofeedback was used during RLVT to assist the motor learning process. Respiratory outcome measures of lung volume initiation, termination and excursion were objectively measured using respiratory plethysmography (InductoTrace), and cepstral and spectral-based acoustic measures were also determined at each time point.

RESULTS

All participants showed improvement in one or more respiratory measures as well as reduced acoustic dysphonia severity following phase 1 of RLVT alone. Two participants achieved further marked improvement in acoustic voice measures after laryngeal-based training was added in phase 2 of treatment, but this was generally also accompanied by further improvement or stabilization of respiratory measures.

CONCLUSION

Results from this preliminary study support the feasibility of RLVT for improving speech breathing behavior, and suggest that RLVT alone can improve objectively measured dysphonia severity.

The Impact of Respiratory Function on Voice in Patients with Presbyphonia

BACKGROUND AND OBJECTIVE

Presbyphonia is an age-related voice disorder characterized by vocal fold atrophy and incomplete glottal closure during phonation. The extent to which the effects of presbyphonia may be compounded by age-related declines in the respiratory system and further impact communication and quality of life remains unknown. Therefore, the objective of this study was to determine how variations in respiratory function impacts voice measures in a sample of participants with presbyphonia.

METHODS

In this pilot study, 21 participants with presbyphonia underwent respiratory assessments (spirometry and respiratory muscle strength testing) and voice assessments (videostroboscopy, acoustic analysis, auditory-perceptual ratings, aerodynamic assessment, and self-assessments). Factor and cluster analyses were conducted to extract voice and respiratory constructs and to identify groups of participants with similar profiles. Correlations and regression analyses were conducted to better describe the relationships between voice and respiratory function.

RESULTS

Respiratory function was found to impact voice via two main pathways: through its physiological effect on voice and through its impact on general health and impairment. A lower respiratory function was associated with a lower vocal fold pliability and regularity of vibration and with an elevated aerodynamic resistance accompanied by laryngeal hyperfunction. Standardized measures of respiratory function were associated with perceived voice-related handicap. Respiratory function did not associate with voice quality, which was mostly influenced by the severity of vocal fold atrophy.

CONCLUSION

Poor respiratory health exacerbates the burden of vocal fold atrophy and, therefore, implementation of respiratory screening prior to starting voice therapy may significantly affect the treatment plan and consequently the outcomes of voice therapy in this patient population.

Effects of Humidification of the Vocal Tract and Respiratory Muscle Training in Women With Voice Symptoms-A Pilot Study

OBJECTIVE

The aim of this study was to determine the efficacy of a 4-week breathing exercise intervention in participants with voice symptoms.

METHODS

Six nonsmoking women (mean age 49) experiencing voice symptoms used a novel device WellO₂ for respiratory exercises that provides counter pressure during both inspiration and expiration and warms and humidifies the breathing air. Speech samples were acoustically (Acoustic Voice Quality Index) and perceptually (grade, roughness, breathiness, asthenia, and strain scale) analyzed, and perceived voice symptoms and self-reported effort in breathing and phonation were obtained. Respiratory measurements included breathing frequency and pattern, peak expiratory flow, forced vital capacity, and forced expiratory volume in 1 minute.

RESULTS

The total scores of Acoustic Voice Quality Index and some of its subcomponents (shimmer and harmonic-to-noise ratio), and the grade, roughness, and strain of the GRBAS scale indicated significantly improved voice quality. However, neither the nature or frequency of the experienced voice symptoms nor the perceived phonatory effort changed as the function of intervention. According to the participants, their breathing was significantly less effortful after the intervention, although no significant changes were observed in the objective respiratory measurements with a spirometer.

CONCLUSION

Training with the WellO₂ device has the potential to improve voice quality. The combination of inspiratory and expiratory training and warmed, humidified air is a multifaceted entity influencing several parts in the physiology of voice production. The effects of using WellO₂ need to be confirmed by further studies with a larger number of participants.

The Effect of Pulmonary Function on the Incidence of Vocal Fatigue Among Teachers

INTRODUCTION

Females face a significantly higher risk of presenting with voice problems than males. This discrepancy has been associated with a number of differences in respiratory behavior and the physiology of the laryngeal and endocrine systems.

METHODS

In conjunction with established spirometry measures, the Vocal Fatigue Index (VFI) was used to determine (1) if there is a relationship between base pulmonary function and vocal fatigue among teachers; and (2) if that relationship is different in females from males. One hundred and twenty-two elementary and middle school teachers (96 females and 26 males) from the Jordan School District in Northern Utah participated in the study.

RESULTS

VFI factors were predictors of the outcomes of several raw spirometry measures for female participants, but the same predictive relationship was not found for male participants. Additionally, there appeared to be no relationship between VFI and spirometry measures in females when using normalized, rather than raw, spirometry metrics.

CONCLUSIONS

The results suggest that the pulmonary physiology that would result in reduced raw pulmonary function, in combination with other differences associated with gender, may lead to a greater incidence of vocal fatigue among female teachers than their male counterparts.

Respiratory and Laryngeal Changes With Vocal Loading in Younger and Older Individuals

PURPOSE

The objective of the current study was to investigate the effects of age and vocal loading on the respiratory and laryngeal systems.

METHOD

Fourteen younger (M = 20 years) and 13 older (M = 75 years) healthy individuals participated in a 40-min vocal loading challenge in the presence of 70-dB background noise. Respiratory kinematic and laryngeal measurements were obtained before and after the challenge.

RESULTS

Following the loading challenge, participants in both groups reported greater speaking effort. Sound pressure level increased in the older group and decreased in the younger group after loading. Younger adults, but not older adults, used lower lung volume initiations and higher lung volume terminations after loading. Cepstral peak prominence increased with loading in both groups, but this change was of small magnitude and not clinically significant.

CONCLUSIONS

The negative effects of loading were observed in respiratory and laryngeal measures, although the pattern of changes differed across the groups. These data increase our knowledge of underlying respiratory and laryngeal physiological changes following a loading challenge and may reflect some of the physiologic mechanisms underlying vocal fatigue.

The Impact of Glottal Configuration on Speech Breathing

OBJECTIVE

The purpose of this study was to examine whether changes in respiratory patterns occurred in response to volitional changes in glottal configuration.

METHODS

Twelve vocally healthy participants read a passage while wearing the Inductotrace respiratory inductive plethysmograph, which measures the excursions of the rib cage and abdomen. Participants read the passage 5 times in a typical speaking voice (baseline phase), 10 times in an experimental voice, which was similar to a breathy vocal quality (experimental phase), and 5 times again in a typical speaking voice (return phase). Kinematic estimates of lung volume (LV) initiation, LV termination, and LV excursion were collected for each speech breath.

RESULTS

Participants spoke with larger LV excursions during the experimental phase, characterized by increased LV initiation and decreased LV termination compared with the baseline phase.

CONCLUSION

In response to volitional changes in glottal configuration, healthy individuals spoke with increased LV excursion. They both responded to changes (decreasing LV termination) and planned for more efficient future utterances (increasing LV initiation) during the experimental phase. This study demonstrated that respiratory patterns change in response to changes in glottal configuration; future work will examine these patterns in individuals with voice disorders.

Long-term Surveillance Following Intralesional Steroid Injection for Benign Vocal Fold Lesions

Importance

The short-term outcomes of vocal fold steroid injection (VFSI) are well documented. However, few studies have reported the long-term outcomes following VFSI.

Objective

To investigate the incidence rates of symptom recurrence and secondary interventions following VFSI for benign vocal fold lesions.

Design, Setting, and Participants

This prospective cohort study was conducted at a tertiary referral medical center in Taipei, Taiwan. The cohort included 189 patients with vocal fold lesions who had received VFSI as the primary treatment between August 2011 and September 2013.

Exposures

All participants underwent VFSI.

Main Outcomes and Measures

Long-term surveillance was conducted through structured telephonic interviews and by reviewing medical charts every 6 months over a 2-year period. We assessed the 10-item voice handicap index, dysphonic symptoms, and whether the patients had received any additional interventions after the initial VFSI.

Results

The 189 participants (32 men and 157 women; mean [SD] age, 39 [10] years [range, 20-74 years] included patients who had undergone VFSI for vocal fold nodules (n = 72), polyps (n = 72), or mucus-retention cysts (n = 45). Following VFSI, 141 patients (74.6%; 23 men and 118 women; mean age, 39 years [range, 20-70 years]) showed positive response (ie, clinically significant symptom resolution without the need for additional procedures) and received long-term surveillance. The median follow-up period was 19.4 months, and 2 patients were lost to follow-up postoperatively within 1 year. The cumulative failure rates (subjective symptom recurrence plus secondary treatments) at 6, 12, 18, and 24 months after VFSI were 12%, 17%, 24%, and 32%, respectively. When the initial response rate to VFSI (141 of 189, 74.6%) was considered altogether, VFSI remained effective after 2 years in 50% of the initially recruited 189 patients. The highest rate of long-term effectiveness of VFSI occurred in vocal polyps (54%), followed by nodules (49%) and cysts (43%).

Conclusions and Relevance

This study demonstrates that VFSI can be beneficial in managing benign vocal lesions, especially when first-line treatments are unsuitable. However, the long-term results of this study clarify that a substantial number of patients experience symptom recurrence or receive subsequent interventions within 2 years after VFSI; this should be considered in medical decision making.

Evidence for Auditory-Motor Impairment in Individuals With Hyperfunctional Voice Disorders

PURPOSE

The vocal auditory-motor control of individuals with hyperfunctional voice disorders was examined using a sensorimotor adaptation paradigm.

METHOD

Nine individuals with hyperfunctional voice disorders and 9 individuals with typical voices produced sustained vowels over 160 trials in 2 separate conditions: (a) while experiencing gradual upward perturbations in the fundamental frequency (fo) of their auditory feedback (shift-up) and (b) under no auditory perturbation (control). The shift-up condition consisted of 4 ordered (fixed) phases: baseline (no perturbation), ramp (gradual increases in heard fo), hold (a consistently higher heard fo), and after-effect (no perturbation). Adaptive responses were defined as the difference in produced fo during control and shift-up conditions.

RESULTS

Adaptive responses were significantly different between groups. Individuals with typical voices generally showed compensatory adaptive responses, with decreased fo during the ramp and hold phases. Conversely, many individuals with hyperfunctional voice disorders instead displayed the opposite effect by following the direction of the perturbation. When fo was experimentally increased, speakers further increased their fo.

CONCLUSION

Results indicate that some individuals diagnosed with hyperfunctional voice disorders have disrupted auditory-motor control, suggesting atypical neurological function. These findings may eventually allow for the development of new interventions for hyperfunctional voice disorders.

Spectral- and Cepstral-Based Acoustic Features of Dysphonic, Strained Voice Quality

Objectives

We sought to determine whether spectral- and cepstral-based acoustic measures were effective in distinguishing dysphonic-strained voice quality from normal voice quality and whether these measures were related to auditory-perceptual ratings of strain severity.

Methods

Voice samples from 23 speakers with dysphonia characterized predominantly by strained voice quality and 23 speakers with normal voice were acoustically analyzed. Measures related to the prominence of the cepstral peak and the ratio of low- to high-frequency spectral energies, as well as the variation of each, were computed from continuous speech and a sustained vowel. Correlations to perceptually rated strain severity were determined.

Results

Measures related to the cepstrum were the strongest discriminators between dysphonic-strained voice and normal voice. Variation in the ratio of low- to high-frequency spectral energies also significantly differentiated the two speaker groups. All measures were significantly correlated with perceptually rated strain severity, including an acoustic severity index that incorporated both cepstral- and spectral-based measures.

Conclusions

Cepstral- and spectral-based measures that have been previously studied in dysphonia characterized by breathiness and roughness are effective in distinguishing strained dysphonia from normal voice quality. The utility of these acoustic measures is supported by their moderate-to-high relationship with perceptually rated strain severity.

The Impact of Cumulative Vocal Demands on Vocal Performance of Student Clinicians in Speech-Language Pathology

Effects of cumulative vocal demands on voice performance of student clinicians majoring in speech-language pathology were observed at three distinct points over the period of an academic semester. Acoustic and aerodynamic voice parameters were monitored in controlled and natural settings; participants also provided subjective information related to their voice usage. Comparisons of voice parameters in student clinicians repeatedly measured throughout an extended period of time did not lead to statistically significant differences. Self-reported data revealed a satisfactory level of knowledge and awareness regarding voice concerns in this population. These outcomes suggested consistent voice stability in this group, over the cycle of an academic semester.

The Effects of Hyper- and Hypocapnia on Phonatory Laryngeal Airway Resistance in Women

PURPOSE

The larynx has a dual role in the regulation of gas flow into and out of the lungs while also establishing resistance required for vocal fold vibration. This study assessed reciprocal relations between phonatory functions-specifically, phonatory laryngeal airway resistance (Rlaw)-and respiratory homeostasis during states of ventilatory gas perturbations.

METHOD

Twenty-four healthy women performed phonatory tasks while exposed to induced hypercapnia (high CO2), hypocapnia (low CO2), and normal breathing (eupnea). Effects of gas perturbations on Rlaw were investigated as were the reciprocal effects of Rlaw modulations on respiratory homeostasis.

RESULTS

Rlaw remained stable despite manipulations of inspired gas concentrations. In contrast, end-tidal CO2 levels increased significantly during all phonatory tasks. Thus, for the conditions tested, Rlaw did not adjust to accommodate ventilatory needs as predicted. Rather, stable Rlaw was spontaneously accomplished at the cost of those needs.

CONCLUSIONS

Findings provide support for a theory of regulation wherein Rlaw may be a control parameter in phonation. Results also provide insight into the influence of phonation on respiration. The work sets the foundation for future studies on laryngeal function during phonation in individuals with lower airway disease and other patient populations.

A comparison of vocal demands with vocal performance among classroom student teachers

PURPOSE

This investigation compared voice performance of student teachers across an academic semester in order to examine the effect of increasing demands on their voice.

METHOD

A repeated measures design was applied to the data analysis: all participants were tested three separate times throughout the semester. The equipments used for monitoring vocal behavior were the Ambulatory Phonation Monitor (APM), the Computerized Speech Lab (CSL), and the Phonatory Aerodynamic System (PAS), which are computer-based systems for acoustic and aerodynamic assessment of voice. Additionally, participants completed surveys related to voice usage.

RESULTS

In this study, most voice parameters of student teachers measured in a natural setting and in a controlled environment indicated changes that revealed progressive instability and noise in the course of an academic semester. Additional comparisons demonstrated differences between voice usage in the school environment and voice produced in the voice lab. Self-reported information demonstrated overall reduced awareness regarding preventive methods for voice disorders.

CONCLUSIONS

Based on the results of this study, increased teaching-related voice demands associated with reduced awareness of voice production and preventive measures of voice disorders may have a detrimental impact on voice performance, leading to a risk of developing voice disorders.

LEARNING OUTCOMES

Participants will recognize the importance of clarifying and quantifying the relationship of vocal demands and voice performance among student teachers.

Avaliação eletroglotográfica de mulheres disfônicas com lesão de massa

OBJETIVO: comparar os resultados da avaliação eletroglotográfica entre mulheres adultas com laudo otorrinolaringológico de nódulos vocais e presença de fenda glótica com mulheres sem alterações laríngeas. MÉTODO: trata-se de 20 mulheres, sendo 10 com exame otorrinolaringológico de nódulo vocal, associado à fenda glótica, e 10 com vozes avaliadas na análise perceptivo-auditiva como neutras e avaliação otorrinolaringológica sem alteração laríngea. A faixa etária variou de 27 a 55 anos, com média de 37,60 e 36,00 para grupo estudo e controle, respectivamente. O material de voz foi a emissão habitual da vogal sustentada /a/. Foram extraídas as medidas de quociente de contato, frequência fundamental, jitter, bem como a classificação e interpretação dos tipos de ondas e presença do joelho eletroglotográfico. A análise estatística foi realizada pelo teste Exato de Fisher e T de Student. RESULTADOS: todos os traçados foram classificados como tipo II (100%). Não foi observada diferença na presença ou ausência de joelho entre grupos. A média do quociente de contato foi de 42,52 e 45,56 para grupo estudo e controle, respectivamente. Apesar do menor valor para o grupo estudado, não houve diferença significante entre grupos. Houve relação estatisticamente significante entre grupos no que se refere à frequência fundamental e jitter. A média da frequência fundamental foi 193,18 e 211,69 e o valor médio de jitter foi 1,21 e 2,9 para o grupo estudo e controle, respectivamente. CONCLUSÃO: mulheres com lesão de massa nas pregas vocais apresentam maiores valores de jitter e menores valores para frequência fundamental eletroglotográfica.

The inability to produce soft voice (IPSV): a tool to detect vocal change in school-teachers

PURPOSE

This study investigated whether clinicians could detect voice changes reported by teachers, from self-ratings teachers conducted of their inability to produce soft voice (IPSV).

METHODS

Ten teachers wore a vocal dosimeter and completed daily IPSV ratings approximately every 2 hours for 14 days. Following the 2 weeks of dosimetry, two speech clinicians specialized in voice rated the teachers' IPSV from dosimeter recordings. Teacher and clinician ratings were compared for each participant.

RESULTS

Although agreement between teacher and clinician ratings was not significant, descriptive analyses demonstrated an average difference score of 1.7 (SD 1.4) between teacher and clinician ratings.

CONCLUSIONS

This study supports the potential usefulness of the IPSV as a simple tool to detect voice changes in oneself or others.

Multiple forebrain systems converge on motor neurons innervating the thyroarytenoid muscle

The present study investigated the central connections of motor neurons innervating the thyroarytenoid laryngeal muscle that is active in swallowing, respiration and vocalization. In both intact and sympathectomized rats, the pseudorabies virus (PRV) was inoculated into the muscle. After initial infection of laryngomotor neurons in the ipsilateral loose division of the nucleus ambiguus (NA) by 3 days post-inoculation, PRV spread to the ipsilateral compact portion of the NA, the central and intermediate divisions of the nucleus tractus solitarii, the Botzinger complex, and the parvicellular reticular formation by 4 days. Infection was subsequently expanded to include the ipsilateral granular and dysgranular parietal insular cortex, the ipsilateral medial division of the central nucleus of the amygdala, the lateral, paraventricular, ventrolateral and medial preoptic nuclei of the hypothalamus (generally bilaterally), the lateral periaqueductal gray, the A7 and oral and caudal pontine nuclei. At the latest time points sampled post-inoculation (5 days), infected neurons were identified in the ipsilateral agranular insular cortex, the caudal parietal insular cortex, the anterior cingulate cortex, and the contralateral motor cortex. In the amygdala, infection had spread to the lateral central nucleus and the parvicellular portion of the basolateral nucleus. Hypothalamic infection was largely characterized by an increase in the number of infected cells in earlier infected regions though the posterior, dorsomedial, tuberomammillary and mammillary nuclei contained infected cells. Comparison with previous connectional data suggests PRV followed three interconnected systems originating in the forebrain; a bilateral system including the ventral anterior cingulate cortex, periaqueductal gray and ventral respiratory group; an ipsilateral system involving the parietal insular cortex, central nucleus of the amygdala and parvicellular reticular formation, and a minor contralateral system originating in motor cortex. Hypothalamic innervation involved several functionally specific nuclei. Overall, the data imply complex CNS control over the multi-functional thyroarytenoid muscle.