Closed-loop network of skin-interfaced wireless devices for quantifying vocal fatigue and providing user feedback.

Vocal fatigue is a measurable form of performance fatigue resulting from overuse of the voice and is characterized by negative vocal adaptation. Vocal dose refers to cumulative exposure of the vocal fold tissue to vibration. Professionals with high vocal demands, such as singers and teachers, are especially prone to vocal fatigue. Failure to adjust habits can lead to compensatory lapses in vocal technique and an increased risk of vocal fold injury. Quantifying and recording vocal dose to inform individuals about potential overuse is an important step toward mitigating vocal fatigue. Previous work establishes vocal dosimetry methods, that is, processes to quantify vocal fold vibration dose but with bulky, wired devices that are not amenable to continuous use during natural daily activities; these previously reported systems also provide limited mechanisms for real-time user feedback. This study introduces a soft, wireless, skin-conformal technology that gently mounts on the upper chest to capture vibratory responses associated with vocalization in a manner that is immune to ambient noises. Pairing with a separate, wirelessly linked device supports haptic feedback to the user based on quantitative thresholds in vocal usage. A machine learning-based approach enables precise vocal dosimetry from the recorded data, to support personalized, real-time quantitation and feedback. These systems have strong potential to guide healthy behaviors in vocal use.

Singing more, singing harsher: occurrence of nonlinear phenomena in a primate' song.

Nonlinear phenomena (NLP) in animal vocalizations arise from irregularities in the oscillation of the vocal folds. Various non-mutually exclusive hypotheses have been put forward to explain the occurrence of NLP, from adaptive to physiological ones. Non-human primates often display NLP in their vocalizations, yet the communicative role of these features, if any, is still unclear. We here investigate the occurrence of NLP in the song of a singing primate, the indri (Indri indri), testing for the effect of sex, age, season, and duration of the vocal display on their emission. Our results show that NLP occurrence in indri depends on phonation, i.e., the cumulative duration of all the units emitted by an individual, and that NLP have higher probability to be emitted in the later stages of the song, probably due to the fatigue indris may experience while singing. Furthermore, NLP happen earlier in the vocal display of adult females than in that of the adult males, and this is probably due to the fact that fatigue occurs earlier in the former because of a greater contribution within the song. Our findings suggest, therefore, that indris may be subjected to physiological constraints during the singing process which may impair the production of harmonic sounds. However, indris may still benefit from emitting NLP by strengthening the loudness of their signals for better advertising their presence to the neighboring conspecific groups.

Multiparametric analysis of voice following prolonged voice use and voice rest in teachers: evidence from discriminant analysis.

PURPOSE: Even though recent investigations have used multiparametric protocol, the set of robust parameters in determining the effects of vocal fatigue and voice rest in teachers is not clear. The first objective of the study was to document the impact of prolonged voice use and voice rest on the subjective and objective voice parameters among Indian secondary school teachers. The second objective was to determine the set voice parameters sensitive to vocal changes resulting from continuous voice use and voice rest. METHOD: The study included 15 male and 15 female secondary school teachers with a clinically normal voice and no history of voice disorders. Phonation samples were recorded in three different conditions, i.e., condition 1 (before voice use), condition 2 (following voice use), and condition 3 (following voice rest). The vocal Fatigue Index (version 2) was administered before the voice recordings in all three conditions. The objective parameters, namely fundamental frequency, range of fundamental frequency, jitter (%), shimmer (%), harmonic to noise ratio, and smoothened cepstral peak prominence, were extracted. RESULTS: Results revealed that fundamental frequency, jitter, shimmer, Harmonic to noise ratio, and smoothened cepstral peak prominence were significantly different across the three conditions. The discriminant analysis revealed that only three parameters classified 98.3% of samples accurately between the three conditions. CONCLUSION: Further research on the correlation between the other subjective and the objective parameters of voice after vocal fatigue would provide more penetrating and ample in-depth insights into the assessment and quantification of vocal fatigue.

Patients' perspective about speech, swallowing and hearing status post-SARS-CoV-2 (COVID-19) recovery: E-survey.

OBJECTIVE: The present study investigates the COVID-19 survivors' perspective on speech, swallowing, and hearing-related issues post-COVID-19. We further investigate the recovery duration for speech, swallowing, and hearing-related symptoms post-COVID. DESIGN: Survey study; E-survey. METHODOLOGY: A total of 78 subjects (35.78 years ± 11.93) participated in the survey. All the participants were diagnosed with the RTPCR method. To understand the recovery duration for the speech, swallowing and hearing issues post-COVID-19, we conducted a three-phase study. RESULTS: In the first phase of the survey, 68 subjects reported symptoms related to speech, swallowing, and hearing issues 15 days of post-COVID recovery. A total of 76.4% of subjects reported only swallowing-related issues, 4.41% only speech-related issues, whereas 1.47% reported the problem in speech and hearing functions. The 2nd phase of the study was conducted after the first phase of the study. Only 22 subjects reported the presence of swallowing, speech and hearing-related issues from the 68 subjects. During the last phase, only 12 subjects reported speech, swallowing, and hearing issues. All subjects recovered from the olfaction and gustation impairment, whereas 50% of subjects reported the presence of xerostomia. CONCLUSION: From the present study, we conclude that the SARC-CoV-2 virus directly affects the respiratory system and affects the aero-digestive system and laryngeal system physiology. Individuals with comorbid conditions admitted in ICU during COVID-19 treatment and prolonged hospital stay were at higher risk of developing speech, swallowing, and hearing-related issues post-COVID-19. The present study indicated that all COVID-19 survivors should be screened for speech, swallowing, and hearing-related issues for early rehabilitation if needed.

[Vocal fatigue as an indicator of complex voice disorders-a diagnostic and therapeutic challenge]. / Vocal Fatigue als Indikator für komplexe Stimmstörungen ­ eine diagnostische und therapeutische Herausforderung.

Vocal fatigue is increasingly observed among professional voice users (e.g., teachers). This pathologic state is associated with restrictions in everyday life and is considered to be an indicator of complex voice disorders. Since there are few systematic studies on the phenomenon, there is currently no uniform definition or diagnostic workup. Based on the case study of a professional speaker, possibilities for a structured vocal fatigue assessment are presented. These are discussed with regard to their laryngoscopic, instrumental acoustic ("performance fatigue") and subjective symptom-related characteristics ("perceived fatigue"). In addition, a differentiation from the vocal effort, vocal demand, and vocal demand response models according to Hunter et al. (2020) is made.

Vocal resistance among choir singers.

PURPOSE: The purpose of the present study was to compare the voice of choir singers before and after 60 min of singing and after an absolute rest. METHODS: Twenty-one female choir singers aged on average 26.59 years, with experience in choir singing of at least one year were instructed to emit the vowel /a/ before and after singing and after a vocal rest of 30 min for an analysis of acoustic measures, and for the evaluation of their tactile-kinesthetic self-perception. Vocal warm-up was performed for 10 min. The participants were instructed to sing the "Ave Verum" music continuously for 60 min. RESULTS: f0 (p = 0.0001) and Flo (p = 0.0002) increased after the singing test and were reduced after the vocal rest, in contrast to Fhi (p = 0.001), which continued to be increased compared to the pre-test measure even after the vocal rest. The vAm parameter (p = 0.05) was reduced after continuous singing and rest. All self-evaluation symptoms increased after the continuous singing task and were reduced after the 30 min rest, except for complaints of low voice, pain when swallowing and cough/throat clearing. CONCLUSION: 60 min of continuous use of the singing voice induced signs of vocal fatigue with an increase in f0, with improvement of symptoms and a reduction of f0 occurring after 30 min of vocal rest.

Comparison of vocal fatigue and vocal tract discomfort between teachers of normal pupils and teachers of mentally disabled pupils.

PURPOSE: This study aims to study the comparison of vocal fatigue and vocal tract discomfort between teachers of normal pupils and teachers of mentally disabled pupils. STUDY DESIGN: Cross-sectional study METHODS: Participants were 179 teachers (50 male, 129 female) and 30 non-teachers (14 male, 16 female) who participated in the current study. The teachers work in elementary schools. Furthermore, 87 of the teachers work for mentally disabled pupils at special elementary schools. Non-teachers were Ahvaz Jundishapur University of Medical Sciences employees who consider as the control group. They completed the Persian VFI and VTDp questionnaires three times, at the beginning, middle, and end of their office hours for 1 workday. RESULTS: The current study's findings indicate that the Persian VFI and VTD scores of non-teachers were significantly lower than teachers' scores. Furthermore, teachers of mentally disabled pupils demonstrated higher values from teachers of normal pupils based on the Persian VFI and VTDp scores CONCLUSION: The study results showed that teachers experienced more vocal fatigue and vocal tract discomfort than non-teachers. Furthermore, teachers of mentally disabled pupils indicated more vocal fatigue, the larynx's physical discomfort, and vocal tract discomfort, but this difference was practically small.

Relations between Creaky Voice and Vocal Symptoms of Fatigue.

BACKGROUND: The use of a creaky voice in speech has become more common. Laryngeal findings relate creaky voice with strong adductive tension in the glottis, and thus it may be expected to be related to an increased risk of vocal fatigue. METHODS: The present study investigated the relation of creaky voice use and vocal symptoms in 104 Finnish female university students (mean age 24.3 years, SD 6.3 years). They had no known pathology of voice or hearing. The participants were recorded while reading aloud a text of approximately 40 s in duration. They also filled in a questionnaire consisting of the Voice Handicap Index (VHI, translation in Finnish), and half of them also answered questions about the frequency and severity of symptoms of vocal fatigue. The samples were perceptually analysed for the amount of creakiness and strain by a speech therapist and a voice trainer. RESULTS: The interrater reliability of the listeners was acceptable (Pearson's χ2 = 100.159, p = 0.000 for creak; χ2 = 69.199, p = 0.000 for strain). Neither creakiness nor strain correlated with vocal symptoms. Participants with a low and a high amount of creakiness or strain did not differ from each other in terms of vocal symptoms or VHI scores. Symptoms' total score correlated with VHI total score and total scores of VHI's physical subscale. Creakiness and strain correlated positively with each other (r = 0.40, p = 0.000). CONCLUSION: No significant relations were found between creakiness or strain and vocal symptoms in this sample of university students.

[Pretesting of the German Vocal Fatigue Index (VFI-D)-transcultural translation and cross validation]. / Prätestung des deutschen Vocal Fatigue Index (VFI-D) ­ transkulturelle Übersetzung und Kreuzvalidierung.

BACKGROUND: In clinical routine, vocal fatigue is a common symptom in patients with dysphonia. OBJECTIVE: The aim of this study was to conduct a transcultural translation of the Vocal Fatigue Index (VFI), a standardized subjective questionnaire. Furthermore, pretesting and prevalidation were performed in 20 subjects, with comparison to the Voice Handicap Index (VHI­9i) and the Vocal Tract Discomfort Scale (VTD). MATERIALS AND METHODS: The translation, content review, and pretest of the German Vocal Fatigue Index (VFI-D) was divided into four sections: 1. transcultural translation, 2. expert voting on comprehensibility, 3. test of comprehensibility through cognitive interviews in 15 participants, 4. pretest of the VFI­D with cross validation compared to VHI­9i and VTD in 20 subjects. This process corresponds to current standards for transcultural translation and adaptation of questionnaires. RESULTS: According to expert voting and cognitive testing, the VFI­D is correct and comprehensible (intercoder reliability κ = 0.66). The factor analysis revealed three distinguishable parts: VFI­D part 1 correlates strongly with VHI­9i and VTD, VFI­D part 2 with VTD only (rho ≈ 0.800 each), and VFI­D part 3 correlates only weakly with VHI­9i and VTD (rho ≈ 0.585). Thus, convergence and divergence validity are proven. CONCLUSION: The first German version of the VFI­D might be a base for further research on symptoms, causes, and treatment options in vocal fatigue. Particularly patients in voice-intensive professions may benefit.

Reliability and validity of the Turkish version of the Vocal Fatigue Index

Background/aim: The aim of this study is to evaluate the reliability and validity of the Turkish version of the Vocal Fatigue Index (VFI). Materials and methods: The study was conducted with 535 participants including 285 patients with voice disorders and 250 healthy controls. Internal consistency and test-retest reliability were calculated for the reliability analysis. The mean VFI factor scores of both groups were compared. The strength and direction of the relation between VFI and Voice-Related Quality of Life (V-RQOL) measure was evaluated for the validity analysis. Results: The Cronbach's alpha coefficient of VFI factor scores was found to be 0.920 for tiredness and avoidance of voice use, 0.879 for physical discomfort with voice use, and 0.882 for improvement of symptoms with voice rest. The test-retest reliability revealed 0.877 for the tiredness and avoidance of voice use, 0.913 for the physical discomfort with voice use, and 0.820 for the improvement of symptoms with voice rest. When compared with healthy individuals, VFI factor scores were statistically significant higher in patients with voice disorders. The V-RQOL scores decreased significantly as the VFI scores increased. Conclusion: The Turkish version of the VFI is a good reliable and valid instrument for evaluating vocal fatigue symptoms in the Turkish-speaking community.

The Effect of Classroom Capacity on Vocal Fatigue as Quantified by the Vocal Fatigue Index.

OBJECTIVE: Previous research has concluded that teachers are at a higher-than-normal risk for voice issues that can cause occupational limitations. While some risk factors have been identified, there are still many unknowns. PATIENTS AND METHODS: A survey was distributed electronically with 506 female teacher respondents. The survey included questions to quantify three aspects of vocal fatigue as captured by the Vocal Fatigue Index (VFI): (1) general tiredness of voice (performance), (2) physical discomfort associated with voicing (pain), and (3) improvement of symptoms with rest (recovery). The effect of classroom capacity on US teachers' self-reported experience of vocal fatigue was analyzed. RESULTS: The results indicated that a classroom's capacity significantly affected teachers' reported amounts of vocal fatigue, while a teacher's age also appeared to significantly affect the reported amount of vocal fatigue. A quadratic rather than linear effect was seen, with the largest age effect occurring at around 40-45 years in all three factors of the VFI. CONCLUSION: Further factors which may affect vocal fatigue must be explored in future research. By understanding what increases the risk for vocal fatigue, educators and school administrators can take precautions to mitigate the occupational risk of short- and long-term vocal health issues in school teachers.

Videokymographic Visualization of Phonasthenia: A Nonorganic Voice Disorder.

BACKGROUND: Phonasthenia is a voice disorder where the larynx looks essentially normal and dysphonia is not heard but felt by the patient. This study aims to use videokymography (VKG) to detect any abnormalities in the vibratory pattern in phonasthenia and to find out whether or not these abnormalities change after vocal loading. METHODS: Thirty-seven phonasthenic patients and 31 normal subjects participated in a detailed protocol, including analysis of subjective complaints and videokymographic quasi-objective parameters (baseline) followed by loading their voices through prolonged loud reading for 45 min. A second evaluation (experimental) was done after loading. RESULTS: Before vocal loading, patients had significantly more symptoms in all questionnaire questions and higher maximum width difference in VKG than controls. When pre- and postloading values were compared, both groups experienced more symptoms after loading (significant in most of the questions), while the pre- and post-VKG parameters did not show significant differences neither in patients nor controls. On comparing their percent change, the only statistically significant difference between the 2 groups was a greater change in the total score of the questionnaire in the control group. CONCLUSION: Patients had more vocal fatigue symptoms and more amplitude asymmetry between left and right vocal folds than normal subjects.

Early Assessment of Voice Problems in Post-Thyroidectomy Syndrome Using Cepstral Analysis.

Post-thyroidectomy syndrome (PTS), characterized by voice issues after thyroidectomy without recurrent laryngeal nerve injury, was investigated in this study. The Voice Fatigue Index (VFI) and cepstral analysis were employed for subjective and objective voice evaluation. Retrospective analysis involved 96 patients (37 males, 59 females) who underwent thyroidectomy without nerve injury from April 2018 to June 2022. Assessments pre- and post-thyroidectomy included the Voice Handicap Index (VHI) and VFI, along with auditory perceptual, acoustic (including cepstral), aerodynamic, and glottal vibration analyses. In females, although the GRBAS scale showed no significant change, both VHI and VFI increased post-thyroidectomy. Significant correlations were observed between the VHI and VFI in females. Acoustic analysis indicated a decrease in the cepstral peak prominence (CPP) of vowels (/a/) and sentences in females, with significant correlations between changes in the CPP/a/ and VHI/VFI. The maximum fundamental frequency (F0max) exhibited a significant decrease, correlating with the VHI and VFI changes. The VFI demonstrated effectiveness in subjective PTS voice evaluation, comparable to the VHI. The present study highlights the potential of cepstral analysis as an index reflecting subjective voice discomfort, suggesting its promise for a comprehensive PTS voice evaluation.

Prevalence of Vocal Fatigue Due to the Use of Facial Protective Gear in Teaching Medical Professionals.

Since the COVID-19 pandemic, masks have become far more widely used by doctors and are now commonplace in the hospital, with many professionals still wearing them for extended amounts of time. Emerging literature describing numerous mask-related difficulties prompted the authors to conduct a study aimed at assessing the self-perceived impact on voices of teaching doctors due to facial protective gear. In this study carried out from October 2021 to March 2022, data was gathered from 170 pre-, para-, and clinical professionals who were involved in offline teaching. Over half of teaching medical professionals were found to be vocally fatigued. Pre and para-clinical professionals have greater vocal tiredness and avoidance than clinical doctors (p = 0.016). The type of mask used does not make a significant difference in degree of vocal fatigue. Individuals with lingering respiratory difficulties following COVID-19 were significantly more vocally fatigued than their recovered peers (p value for tiredness and avoidance = 0.010). Thus, teaching doctors are at risk of impaired quality of life due to vocal fatigue. Further research on vocal habits and rest practices in the study population may help identify the most effective interventions. Supplementary Information: The online version contains supplementary material available at 10.1007/s12070-023-04350-8.

Measuring Vocal Fatigability in Teachers: The Vocal Fatigability Scale for Teachers (VFS-T).

OBJECTIVES: This study focuses on the distinction between vocal fatigability and vocal fatigue (VF), highlighting the importance of vocal fatigability when assessing teachers' quality of life. Vocal fatigability is more critical for quality of life than performance or perceived VF because it considers the accumulation and chronicity of fatigue over isolated tasks. The objectives are to develop and validate the Vocal Fatigability Scale for Teachers (VFS-T), to assess teachers' levels of vocal fatigability, and to analyze variations based on personal and occupational traits. The VFS-T construct encompasses items related to vocal sensations and performance, their connection to accumulated demanding vocal activity, descriptions of recovery strategies, necessary rest periods, and the impact of VF on daily activities. STUDY DESIGN: A single cross-sectional study with an ex post facto design was conducted. METHODS: The sample consisted of 184 active teachers with various vocal conditions. They completed the VFS-T questionnaire, provided personal and occupational data, and completed the VHI-10 questionnaire. The data collected were analyzed for item refinement, internal structure, reliability, validity, diagnostic capacity, cutoff values, and group differences. RESULTS: The item refinement and internal structure analysis revealed a scale comprising 17 items grouped into two factors. The VFS-T shows good reliability and validity, with cutoffs at <15 for no fatigability, 15-27 for moderate fatigability, and >28 for high fatigability. Most teachers fall into the moderate fatigability range, with 72% experiencing vocal fatigability. CONCLUSIONS: The VFS-T is a reliable tool for detecting vocal fatigability in teachers. This scale focuses on the construct of vocal fatigability, which is related to chronicity of VF and limitations in daily activities in teachers.

Vocal Fatigue Experiences and Mitigation Strategies in the Sacred Harp Singing Community.

OBJECTIVES: Sacred Harp singers sing at a high volume for sustained periods of time without collective warm-up or cool-down exercises, ostensibly putting them at elevated risk for vocal fatigue (VF) and associated vocal pathologies. Participants are also likely to lack formal vocal training. The purpose of this study was to (1) assess singers' experiences with VF, (2) document singers' strategies for mitigating VF, and (3) determine whether vocal training was associated with decreased vocal difficulties. STUDY DESIGN: Self-reporting via online questionnaire containing quantitative and qualitative items. METHODS: This study employed an online questionnaire that combined demographic items, open-ended questions, and the Evaluation of the Ability to Sing Easily (EASE). Participants were recruited at one in-person event and via social media and a mailing list. RESULTS: This study returned 134 valid responses. Singers with formal choral experience scored lower on the EASE and two subscales, but length of experience had no impact. There were no correlations between vocal training and EASE scores. Women scored higher on the EASE than men and nonbinary individuals, while age, length of experience with Sacred Harp singing, and frequency of attendance at annual singing events were all negatively correlated with EASE score. Singers reported a wide range of mitigation strategies, most of which are unique to the Sacred Harp context. CONCLUSIONS: Sacred Harp singers do not appear to struggle more with VF than other populations of singers. However, a few characteristics of their practice put them at risk, and many singers would benefit from professional guidance concerning vocal health.

Psychometric Properties of the Vocal Fatigue Handicap Questionnaire in Kannada Among Teachers.

BACKGROUND: As the literature review suggests, most professional voice users, such as teachers and singers, are prone to vocal abuse or misuse and frequently experience vocal fatigue. Therefore, validating the Vocal Fatigue Handicap Questionnaire among professional voice users with and without the symptoms of vocal fatigue might provide appropriate external validity of the questionnaire. OBJECTIVE: The objective of the study was to validate the Kannada version of the Vocal Fatigue Handicap Questionnaire (VFHQ-K) among a cohort of Kannada-speaking primary and secondary school teachers with and without self-reported vocal fatigue symptoms. STUDY DESIGN: This was a validation study. METHOD: The study consisted of two groups of participants. Group 1 included 40 teachers with self-reported vocal fatigue symptoms, and Group 2 included 57 teachers without self-reported vocal fatigue symptoms. The VFHQ-K was administered to each participant after obtaining informed consent. The questionnaire was again readministered between 1 and 2 weeks to assess the test-retest reliability. All the responses that were obtained were tabulated for analysis. RESULTS: The VFHQ-K demonstrated good test-retest reliability, internal consistency, and acceptable discriminant validity. The cutoff value of VFHQ-K obtained in the present study between the teachers with and without self-reported symptoms of vocal fatigue was much less than the cutoff values reported by the earlier version of VFHQ-K. CONCLUSION: The VFHQ-K can be a helpful tool in the early identification of teachers with vocal fatigue and in improving the vocal health of professional voice users.

Phonatory Tasks and Outcome Measures for Assessing Vocal Fatigue: A Scoping Review.

OBJECTIVES: To map the phonatory tasks and the result measures used to evaluate vocal fatigue in vocally healthy individuals. METHODS: This is a scoping review based on the following research question: What are the phonatory tasks and outcome measures used for the evaluation of vocal fatigue in vocally healthy individuals? The construction of the search strategy followed the PCC strategy; population: vocally healthy adult individuals; concept: phonatory tasks and vocal evaluation measures; and context: vocal fatigue. The search was performed electronically in the databases Medline (PubMed), LILACS (BVS), SCOPUS (Elsevier), Web of Science (Clarivate), EMBASE, and COCHRANE. A manual search in the references of the selected articles and in the journal with the highest number of publications was also performed. The selection of articles was based on reading the titles, abstracts, and full text, applying the eligibility criteria. The selected articles were related to the evaluation of vocal fatigue in healthy individuals from a predetermined vocal load task. Data regarding the characteristics of the publication, sample, phonatory tasks, and outcomes were extracted. The results were presented in a descriptive format, due to a frequency distribution analysis. RESULTS: In total, 3756 studies were identified during the search, of which 60 were selected. The most used vocal load activity was the reading task, with duration ranging from 46 to 120 minutes. The (1) sustained vowel /a/ and (2) the reading of texts and phrases, both in usual intensity and frequency without the interference of the researcher, were the most used evaluation tasks. The most used outcome measures are the following: (1) acoustic parameters-fundamental frequency [fo] (mean, variance), sound pressure level (mean), local jitter (%), local shimmer (%), cepstral peak prominence (mean); (2) vocal self-assessment by the validated instruments-Perceived Phonatory Effort Scale, Visual Analog Scale, Borg-CR-10 Scale. CONCLUSIONS: There is a diversity of phonatory tasks and outcome measures recurrently used in scientific articles to evaluate the signs of vocal fatigue in vocally healthy individuals. The most used vocal sample to evaluate vocal fatigue was the sustained vowel /a/ in habitual intensity and frequency without the interference of the researcher. The most frequently reported outcome measures for the assessment of immediate vocal fatigue effects were the acoustic analysis and vocal self-assessment.

Effects of Back Pressure on the Feasibility and Tolerability of Laryngeal Diadochokinetic Exercise: A Pilot Study.

BACKGROUND: The term vocal demand response refers to how speakers meet vocal demands. Vocal loading tasks with predetermined demand parameters (duration, pitch, loudness, etc) have been used in research to study the vocal demand response; these have historically consisted of loud sustained vowel and loud speech tasks. Tasks founded on laryngeal diadochokinesis (LDDK) may be viable alternatives, especially if demand parameters such as exercise-rest ratio and fluid back pressure are concurrently modulated. OBJECTIVES: To explore the effects of four fluid back pressure conditions (0, 5, 10, and 15 cm H2O) on several measures of subjective participant experience, feasibility, and tolerability during intervallic laryngeal diadochokinetic exercise. METHODS: Participants (n = 12) completed 15-minute trials of LDDK in 30-second rest and exercise intervals against four counterbalanced back pressure conditions: 0, 5, 10, and 15 cm H2O. The effects of back pressure on (1) ratings of perceived vocal exertion, (2) prevalence of adverse effects such as shortness of breath or lightheadedness, (3) subjective difficulty of sustaining LDDK, (4) number of exercise intervals completed, (5) rankings of participant-preferred back pressure levels, and (6) expert ratings of auditory-perceptual diadochokinetic strength were assessed descriptively. RESULTS: Perceived vocal exertion, lightheadedness, and subjective laryngeal diadochokinetic difficulty increased as back pressure increased. Number of intervals completed, auditory-perceptual diadochokinetic strength, and participant rankings of back pressure conditions, by contrast, decreased as back pressure increased. 0 and 5 cm H2O were the most preferred back pressure conditions overall. DISCUSSION: Fluid back pressure was feasible and broadly tolerated during 15-minute trials of vocal exercise. However, the transition from 5 → 10 cm H2O appeared to represent an inflection point in our results: a minority of participants did not tolerate exercise at 10 cm H2O, becoming a majority at 15 cm H2O. We conclude that fluid back pressure should be restricted to values between 0 and 10 cm H2O during LDDK.

Glottal Imaging Study Comparing Vowel Phonation with Semioccluded Vocal Tract Exercises (SOVTEs) Produced Loudly.

OBJECTIVES: This study aimed to estimate vocal loading in loud phonation of a vowel and two widely used semiocclusion voice exercises (SOVTEs). Impact stress (IS) was estimated from glottal closing speed, inertial forces from the second derivative of glottal opening and closing. STUDY DESIGN: Experimental study in vivo. METHODS: A vocally healthy male sustained the [o:] vowel with habitual loudness and loudly: (1) without a tube, (2) into a silicone "Lax Vox" type tube (35 cm in length, 10 mm in diameter) outer end submerged 10 cm in water, and (3) into a straw (length 12.6 cm, diameter 2.5 mm) the outer end in air. He tried to use equal effort in all loud samples. High-speed video-laryngo-endoscopy was performed with a rigid scope. Oral air pressure (Poral) was registered in a mouthpiece through which the endoscope was inserted into the larynx and to which the tubes were attached air-tightly. RESULTS: Compared with vowel phonation at habitual loudness, mean of maximal glottal width (max GW) increased by 44.1% for loud tube phonation and decreased by 1.8% for loud straw phonation, and mean absolute value of minimum GW time derivative dmin increased by 57.1% for tube and by 29.5% for straw suggesting faster glottal closing. Compared with loud vowel phonation, max GW increased by 22.6% for loud tube phonation, while it decreased by 16.6% for loud straw phonation. For the tube, dmindecreased by 7.6% and for the straw by 23.8%. Maximal acceleration (ACC) and deceleration (DC) values were larger for the tube and smaller for the straw than the values for both vowel phonations. CONCLUSIONS: IS, deduced from dmin, increased in loud SOVTEs compared to vowel phonation at a conversational loudness, but remained lower in loud SOVTEs than in loud vowel phonation, particularly with a narrow straw, which also reduced inertial forces, as suggested by the reduced ACC and DC.