Can vocal economy in phonation be increased with an artificially lengthened vocal tract? A computer modeling study

Comparative Study of Two Semi-Occluded Vocal Tract Protocols: A Randomized Clinical Trial

INTRODUCTION

Semi-occluded vocal tract exercises (SOVTEs) are widely used as a therapeutic tool to create flow resistance in the upper airway. The current study was a randomized controlled clinical trial to establish the efficacy of two SOVTE protocols, flow-resistant tube (FRT) and Lessac-Madsen Resonant Voice Therapy (LMRVT). Exploratory investigations included a noninferiority analysis of FRT to the widely adopted therapy protocol (LMRVT), as well as examining the dosing required to improve acoustic measures and subjective ratings.

METHOD

Sixty-seven participants with voice disorder were randomized into one of five groups: 4-week FRT (n = 14), 8-week FRT (n = 19), 4-week LMRVT (n = 15), 8-week LMRVT (n = 5), and control (n = 14). Voice Handicap Index (VHI) and Vocal Fatigue Index scores were collected pre- and posttreatment. Acoustic analysis using the Acoustic Voice Quality Index was completed. We compared VHI between controls and 8-week FRT and LMRVT, adjusting for pre-VHI using linear regression. We examined the efficacy of 4-week protocols relative to controls and conducted a noninferiority comparison of FRT (4 and 8 weeks) to LMRVT (4 and 8 weeks) using 5- and 10-point margins. Finally, we compared the 4- versus 8-week sessions for both therapies.

RESULTS

A statistically significant reduction of VHI in both 8-week FRT relative to controls (-10.60, 95% CI [-19.80, -1.40], p = .025) and 8-week LMRVT (-15.74, 95% CI [-29.40, -2.08], p = .025) was found. We also found an improvement in 4-week FRT relative to controls (-10.11, 95% CI [-20.03, -0.20], p = .046), but the 4-week LMRVT result was not statistically significant (p = .057). FRT was found to be noninferior to LMRVT in terms of VHI using a 10-point margin (FRT - LMRVT: 0.69, 95% CI [-5.76, 7.15], p = .01), but not using a 5-point margin (p = .054). There were no statistically significant differences in VHI scores between 4- and 8-week sessions for either therapy.

CONCLUSIONS

Both FRT and LMRVT improved VHI scores relative to controls. FRT was noninferior to LMRVT in terms of VHI scores. There were no statistically significant differences in VHI scores between 4- and 8-week therapy sessions.

Efficacy of Long-Term Intensive Straw Phonation Exercise in Air for Hyperfunctional Voice Disorders: A Preliminary Study

PURPOSE

Literature highlights the efficacy of prolonged use of straw phonation for vocally healthy individuals. Nevertheless, minimal studies have examined the prolonged use of single treatment in hyperfunctional voice disorders (HFVD), as straw phonation is used as physiological training to improve voice quality in these individuals. The present study aimed to investigate the long-term intensive training effect of straw phonation exercise in air (SPEA) for HFVD.

METHOD

In a time series design, seven females with HFVD (mean age 42.28years) participated in SPEA for 12 long sessions (30 minutes/session) intensively trained for 3weeks (4days/week). The participant-recorded voice samples were analyzed for aerodynamic measures Aerodynamic Subglottic Pressure (ASP), Airflow Rate (AFR), glottal behavior measures Contact Quotient (CQ), Contact Quotient Range (CQR), acoustic measure Acoustic Voice Quality Index (AVQI), auditory-perceptual Consensus Auditory Perceptual Evaluation of Voice - Kannada (CAPE-V-K), and self-perceptual measure Voice Handicap Index - Kannada (VHI-K) at pre-therapy, mid-therapy, post therapy, and 1-month follow-up timelines. Related Friedman's two-way analysis of variance and post hoc Wilcoxon signed-rank test were used to analyze the change in outcome measures across therapy timelines.

RESULTS

Significant reduction in ASP, CQR, AVQI, CAPE-V-K, and VHI-K measures from pre-therapy to post-therapy and follow-up timelines was observed. Although there was a decrease in AFR and CQ measures from pre therapy to post therapy and follow-up, no significant differences were observed. No significant changes were observed from pre therapy to mid-therapy in any outcome measures, indicating the need for extended therapy duration and regular practice.

CONCLUSION

These findings provide preliminary evidence of implementing the long-term intensive training of SPEA for HFVD with the support of significant outcome measures at various therapy timelines.

The Effect of Phonation into a Glass Tube Immersed in Water Compared to Other Interventions on General Degree of Vocal Deviation, Fundamental Frequency, Sound Pressure Level, and Vocal Self-assessment in Vocally Healthy Individuals: A Systematic Review and Meta-analysis

OBJECTIVE

To analyze the effect of phonation in a glass tube immersed in water compared to other interventions on general degree of vocal deviation, fundamental frequency, sound pressure level, and vocal self-assessment in vocally healthy individuals.

METHODS

This is a systematic review and meta-analysis developed from the research question: "In vocally healthy individuals, what is the effect of phonation into a glass tube immersed in water versus other vocal interventions, other activities, or no intervention on general degree of vocal deviation, fundamental frequency, sound pressure level, and vocal self-assessment?" An electronic search was performed using Medline, LILACS, Cochrane Library, Embase, Web of Science, and SCOPUS databases, and a manual search was performed in the gray literature (Brazilian Digital Library of Theses and Dissertations and OpenGrey), the Journal of Voice, and the citations of the studies. Studies with (P) population of adults with healthy voices, (I) intervention with phonation into a glass tube immersed in water, (C) comparison with other vocal interventions, other activities, or no intervention, (O) outcomes of the general degree of vocal deviation, fundamental frequency, sound pressure level, and vocal self-assessment, and an (S) study with the experimental or quasi-experimental design were included. Risk of bias assessment and meta-analysis of the outcomes were performed.

RESULTS

A total of 457 studies were found in the search; four were selected for the systematic review and meta-analysis. In the risk of bias assessment, there was an uncertain risk of selection and performance bias in 100% of the studies and uncertain risk of detection bias of 75%. All studies had an experimental design, and most of them were conducted on women. In the fundamental frequency analysis, there was no difference between the effect sizes of the interventions (z = 0.471, P = 0.638). In the vocal self-assessment, the estimated odds ratio was 1.31, showing a greater chance of improvement in the intervention group than with the comparison group (z = 3.45, P < 0.001). There were not enough studies to analyze the general degree of vocal deviation and sound pressure level outcomes.

CONCLUSION

Phonation into a glass tube immersed in water has a greater positive effect on vocal self-assessment than other interventions in vocally healthy individuals.

Pressure, Flow, and Glottal Area Waveform Profile Changes During Phonation Using the Acapella Choice Device

INTRODUCTION

Vibratory positive expiratory pressure (PEP) devices are now commonly used as a resource for voice therapy. PEP devices promote improved vocal economy with the added benefit of producing a massage effect in the vocal tract. Although the benefits of PEP devices for voice have already been demonstrated, their impact on the vocal source is still not very clear. This study assesses the impact of phonation into the Acapella Choice (a type of PEP device) on the voice.

METHODS

Three normophonic subjects underwent high-speed videoendoscopy assessment while pressure, flow and electroglottographic data was collected.

RESULTS

Phonation into the Acapella device produces large changes in the pressure and flow profiles consequently affecting the voice source. In specific, when intraoral pressure increases as a consequence of the downward movement of the rocker arm in the Acapella device (reduction of the airflow outlet), phonation is hindered, demonstrated by the lower amplitude of vibration of the vocal folds and weaker modulation of the pressure and flow values by the glottal cycle. When the rocker arm in the Acapella device opens (increasing the airflow outlet), the opposite trend is observed where vocal fold vibration is aided and the modulation of pressure and flow by the vocal cycle increases. Based on the pressure and flow signals, we can assume that the impedance of the vocal tract alternates between two dominant regimes: increased inertive reactance (aided vibration) and increased resistance (hindered vibration).

CONCLUSIONS

PEP devices, such as the Acapella device, are efficient in modulating the pressure and flow profiles in the vocal tract leading to the alternation of glottal vibration from aided to hindered. These changes in the glottal vibration can be considered an additional consequence of the massage effect caused by the Acapella device.

Three-Dimensional Finite Element Modeling of the Singer's Formant Cluster Optimization by Epilaryngeal Narrowing With and Without Velopharyngeal Opening

This study aimed to find the optimal geometrical configuration of the vocal tract (VT) to increase the total acoustic energy output of human voice in the frequency interval 2-3.5 kHz "singer's formant cluster," (SFC) for vowels [a:] and [i:] considering epilaryngeal changes and the velopharyngeal opening (VPO). The study applied 3D volume models of the vocal and nasal tract based on computer tomography images of a female speaker. The epilaryngeal narrowing (EN) increased the total sound pressure level (SPL) and SPL of the SFC by diminishing the frequency difference between acoustic resonances F3 and F4 for [a:] and between F2 and F3 for [i:]. The effect reached its maximum at the low pharynx/epilarynx cross-sectional area ratio 11.4:1 for [a:] and 25:1 for [i:]. The acoustic results obtained with the model optimization are in good agreement with the results of an internationally recognized operatic alto singer. With the EN and the VPO, the VT input reactance was positive over the entire fo singing range (ca 75-1500 Hz). The VPO increased the strength of the SFC and diminished the SPL of F1 for both vowels, but with EN, the SPL decrease was compensated. The effect of EN is not linear and depends on the vowel. Both the EN and the VPO alone and together can support (singing) voice production.

Extrinsic Laryngeal Muscle Activity and Vocal Economy in Professionally Trained Voices During Vocal Vibrato

PURPOSE

The purpose of the present study was to determine the extrinsic laryngeal muscle activity and vocal economy during two different singing conditions (straight-tone- vs vibrato singing) over a physiologically relevant singing range.

METHODS

Thirty professional singers or voice coaches participated in the study. The participants sang a sustained /a:/ vowel for approximately 5seconds, once in straight-tone singing conditions and once more in vibrato. The target pitches were C3, F3, A3, C4, F4, A4, and C5. Surface electromyographic (sEMG) measures were performed in the infrahyoid (IH)- and the suprahyoid (SH) muscle region. Contact quotient (CQ), sound pressure level (SPL), and fundamental frequencies were measured to derive the electroglottographic-based vocal economy parameter quasi-output cost ratio (QOCR).

RESULTS

sEMG measures show that IH and SH muscles significantly increased in activity with ascending pitch. IH and SH muscle activity was also significantly higher when singing in vibrato than straight-tone. Moreover, SPL also increased with ascending pitch and when sung in vibrato. CQ increased and QOCR decreased as pitch ascended but did not significantly change when sung in vibrato.

CONCLUSION

Singing higher pitches was generally associated with higher extrinsic laryngeal muscle activity and lower QOCR values. When comparing two singing conditions, extrinsic laryngeal muscle activity was higher during vibrato, implicating that IH and the SH muscles may contribute to rhythmic pulsations of pitch modulation. Although the QOCR value did not show significant differences between the two singing conditions, a significantly higher SPL during vibrato may offer some acoustical and physiological advantages. Results also indicate that extrinsic muscle activity may not be reliably measure vocal economy.

The Immediate Effect of Straw Phonation in Children With Repaired Cleft Palate

OBJECTIVE

This study aims to investigate the immediate effect of straw phonation on the phonation of Persian-speaking children with repaired cleft palate.

STUDY DESIGN

Quasi-experimental preintervention and postintervention.

METHODS

Seventeen children with repaired cleft palate and velopharyngeal dysfunction were investigated. A control group was established comprising children without a cleft palate (control group), carefully matched in terms of age and gender. All participants underwent straw phonation and assessment. The assessments were made two times: at baseline and immediately after straw phonation. Each participant performs straw phonation (a short straw measuring 3 mm in inner diameter and 20 cm in length) once for 3 minutes. The acoustic analysis including parameters, such as jitter, shimmer, harmonics-to-noise ratio (HNR), cepstral peak prominence (CPP) parameters, as well as the electroglottography (closed quotient [CQ]) analysis were performed at pretreatment and immediately after treatment.

RESULTS

Compared with the pretreatment values, after-treatment observation demonstrated a significant reduction in Jitter % and Shimmer %, and a significant enhancement in HNR and CPP among children with repaired cleft palate. There is no significant difference in intragroup data in the CPP and CQ in pretreatment.

CONCLUSIONS

The proposed straw phonation technique results in an immediate positive change in the quality of voice in both groups. Moreover, assessments in the clinical group showed a significant decrease in shimmer and jitter perturbation, alongside elevated levels of HNR and CPP subsequent to straw phonation, irrespective of the phonatory task.

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.

Extrinsic Laryngeal Muscle Activity With Different Diameters and Water Depths in a Semi-Occluded Vocal Tract Exercise

PURPOSE

Surface electromyography (sEMG) has been used to evaluate extrinsic laryngeal muscle activity during swallowing and phonation. In the current study, sEMG amplitudes were measured from the infrahyoid and suprahyoid muscles during phonation through a tube submerged in water.

METHOD

The sEMG amplitude values measured from the extrinsic laryngeal muscles and the electroglottographic contact quotient (CQ) were obtained simultaneously from 62 healthy participants (31 men, 31 women) during phonation through a tube at six different depths (2, 4, 7, 10, 15, and 20 cm) while using two tubes with different diameters (1 and 0.5 cm).

RESULTS

With increasing depth, the sEMG amplitude for the suprahyoid muscles increased in men and women. However, sEMG amplitudes for the infrahyoid muscles increased significantly only in men. Tube diameter had a significant effect on the suprahyoid sEMG amplitudes only for men, with higher sEMG amplitudes when phonating with a 1.0-cm tube. CQ values increased with submerged depth for both men and women. Tube diameter affected results such than CQ values were higher for men when using the wider tube and for women with the narrower tube.

CONCLUSIONS

Vocal fold vibratory patterns changed with the depth of tube submersion in water for both men and women, but the patterns of muscle activation differed between the sexes. This suggests that men and women use different strategies when confronted with increased intraoral pressure during semi-occluded vocal tract exercises. In this study, sEMG provided insight into the mechanism for differences between vocally normal individuals and could help detect compensatory muscle activation during tube phonation in water for people with voice disorders.

A Study on Vocal Attack During Voice Therapy Exercises Using Photoglottography

OBJECTIVE

There are various exercises for voice therapy, but current evidence is insufficient to decide the most effective training technique for each type of dysphonia. This study focused on vocal attack as one of the causes of dysphonia. Hence, vocal attack during voice therapy exercises was investigated using photoglottogram (PGG).

METHODS

Eighteen healthy adult subjects (10 males and 8 females) were included in this study. The first to fifth vocal waves during natural voice, hard and soft voice onset, and semi-occluded vocal tract exercises (SOVTE: humming, tubing, and lip trill) were assessed. We also calculated the 25% vocal fold open quotient (OQ) using a PGG and compared these parameters.

RESULTS

The 25% OQ did not show any sex-related differences. In the first wave, the 25% OQ for hard attack was significantly lower than that for soft attack, tongue-out humming, and lip trill. In contrast, the 25% OQ value for soft attack was significantly higher than that for humming, 6 mm tube phonation, and lip trill. The 25% OQ values differed between SOVTE procedures; it was higher for the 13 mm tube phonation than for the 6 mm tube phonation. The 25% OQ at voice onset in the first to fifth waves differed depending on the SOVTE technique, indicating different voice onset patterns.

CONCLUSIONS

These results suggest that appropriate selection of SOVTE tailored for each patient may have benefit in further voice improvement. Future research should focus on conducting a similar study on patients with dysphonia.

Acoustic Effects of Vocal Warm-Up: A 7-Week Longitudinal Case Study

OBJECTIVE

A case study was used to determine which acoustic parameters would be sensitive to a SOVT-based vocal warm-up over the duration of a standard voice treatment.

METHODS

The longitudinal research design consisted of repeated voice measures during 7 weeks from a single subject, a 48-year-old male occupational voice user with a history of voice disorders. A steady phonation and running speech tasks were performed before and after an intensive 1-minute water-resistance voice exercise (WRT). Acoustic assessment of the pre-and postrecordings from each session was obtained with freely accessible software (e.g., Audacity, PRAAT) and acoustic measures (e.g., fundamental frequency, jitter, shimmer, alpha ratio, NHR, HNR, L1L0, Cepstral Peak Prominence smoothed).

RESULTS

After WRT, the analysis indicated that jitter, shimmer, and NHR had a small but statistically significant decrease, while alpha ratio, CPPS, and HNR had a statistically significant increase. For the days where there were six repetitions, there was a larger effect in the later repetitions in the day for some metrics (i.e., alpha ratio, shimmer, NHR, CPPS), while others had the biggest effect in the first two repetitions in a day (i.e., jitter, HNR).

CONCLUSIONS

A short vocal water-resistance voice task had a positive effect on the short-term acoustic voice metrics after each repetition of the exercise, independent of the number of repetitions throughout the day. When five repetitions of this exercise routine occurred, there was a more substantial influence on the proportion of acoustic voice changes.

Immediate and Short-term Effects of Straw Phonation in Air or Water on Vocal Fold Vibration and Supraglottic Activity of Adult Patients with Voice Disorders Visualized with Strobovideolaryngoscopy: A Pilot Study

Purpose The first purpose of this study was to investigate and compare the short-term effects after a semi-occluded vocal tract (SOVT) therapy session consisting of straw phonation (SP) in air or water on vocal fold vibration and supraglottic activity of adult patients with voice disorders, visualized with strobovideolaryngoscopy (SVL). The second purpose of this study was to investigate and compare immediate changes in the patients' vocal fold vibration and supraglottic activity during SP in air or water, visualized with SVL. Methods Twelve adult patients with voice disorders (eight women and four men, mean age 52 years) were assigned randomly to one of two study groups: SP in air or SP in water. Immediately before and after a therapy session of 15 min, participants underwent a rigid SVL to determine the short-term effects of the SP session. At the posttherapy examination, flexible SVL while performing SP was added to determine the effects occurring during SP. The visual-perceptual ratings were performed blindly and in random order by three laryngologists, using the Voice-Vibratory Assessment with Laryngeal Imaging rating form for stroboscopy. ResultsShort-term effects after SP: After the SP-in-air session, the supraglottic mediolateral compression decreased significantly. The SP-in-water session led to significantly increased left vibrational amplitude. Immediate effects during SP: During SP in air, a significantly increased left amplitude and mucosal wave, and significantly decreased mediolateral supraglottic activity, were found. SP in water tended to decrease the vibrational amplitude during performance of the task. A trend toward higher anteroposterior supraglottic compression was observed during both SP in air and water, being more prominent in the latter. Conclusion SP in air led to less false vocal fold adduction and consequently less hyperfunction. The small increment in anteroposterior supraglottic activity during SP in air and water might be related to epilarynx narrowing, an economic phenomenon associated with SOVT exercises. The effects on vibrational amplitude were rather ambiguous. The small reduction in amplitude during SP in water is expected to diminish vocal fold impact stress and therefore creates an ideal basis for voice therapy. The increment in amplitude and mucosal wave during SP in air might indicate insufficient supraglottic pressure to obtain the favorable effects of semi-occlusion. Whether or not the rise in amplitude after the SP-in-water session is due to voice efficiency or voice fatigue remains unknown. Future larger-scale investigation in subgroups of voice patients is needed to explore these hypotheses.

Acoustic, Aerodynamic, Morphometric, and Perceptual Changes During and After Semi-Occluded Vocal Tract Exercise: An Integrative Review

OBJECTIVE

The body of literature discussing the acoustic, aerodynamic, perceptual, and morphometric changes that occur during and after semi-occluded vocal tract exercise (SOVTE) has dramatically expanded within the past 20 years. The current study integrates the literature on SOVTE from the 1990s onward, reviewing the technique's clinically relevant effects in vocally untrained adults both with and without dysphonia. The study aims to give clinicians actionable information on how SOVTEs alter vocal function in both normal and pathological states.

METHODS

The author queried the MEDLINE database for combinations of search terms related to semi-occluded vocal tract exercise. To improve article identification, the author also performed iterative citation webbing in which the reference lists of each article selected for full-text screening were cross-referenced against the articles returned in the initial MEDLINE search. Articles identified by iterative citation webbing that did not appear in the initial MEDLINE search were then screened individually. The second author independently verified adherence to the review's inclusion and exclusion criteria in both the initial search and data extraction phases.

RESULTS

The initial MEDLINE search returned 869 articles, 111 of which passed the title and abstract screening phase. Iterative citation webbing returned an additional 20 studies, resulting in a total of 131 articles that qualified for full-text screening. 53 articles passed full-text screening and were included in the current review.

DISCUSSION

Semi-occluded vocal tract exercise increases the inertive reactance of the glottis, vocal tract, and air column, as well as introducing flow resistance at the level of the lips or velopharyngeal port. Each of these mechanisms yields downstream acoustic, aerodynamic, morphometric, and perceptual changes, including reductions in phonation threshold pressure and perceived phonatory effort, improved spectral characteristics of the acoustic signal, attenuation of vocal fold impact stress as indexed by various metrics such as maximum area declination rate, and alterations to the physical dimensions of the vocal tract. Although few studies examined the duration of these changes post exercise, several RCTs support the assertion that SOVTE's effects can be sustained with regular practice over weeks or months, regardless of current vocal health status.

Effectiveness of Semi-Occluded Vocal Tract Exercises (SOVTEs) in Patients with Dysphonia: A Systematic Review and Meta-Analysis

BACKGROUND

Dysphonia is a disorder characterized by an alteration in the overall quality of the voice which reduces quality of life. Therefore, we assessed the effectiveness of SOVTEs in the management of dysfunctional and organic dysphonia for acoustic, perceptual-auditive, aerodynamic parameters and self-perception of the disease.

METHODS

a systematic review and meta-analysis were conducted. Findings were reported according to the PRISMA statement. Five databases were searched for RCTs and non- or quasi-RCTs. Studies were independently assessed using the Cochrane Risk of bias (RoB) and ROBINS-I tools. Effect sizes (ES) were calculated only at post-treatment. GRADE criteria were used to assess the quality of evidence.

RESULTS

eight articles were included. Studies investigated several SOVTEs, alone or in combination. None of the study was completely judged at low RoB. The quality of evidence resulted very low for each analysis. SOVTEs revealed to be statistically more effective than control interventions in improving F0 (ES: -14.42; CI 95%: -27.16, -1.69); P = 0.03), whereas shimmer did not change significantly (ES: -0.43; CI 95%:-02.02, 1.15; P = 0.59). Not significant changes in favor of control groups were found for jitter (ES: 0.13; CI 95%: -0.14, 0.40; P  = 0.34) and overall gravity in the perceptual-auditory evaluation (ES: 0.13 CI 95%: -0.50, 0.77; P = 0. 68). Among secondary outcomes, evidence suggested that SOVTEs are more effective than control interventions in Psub reduction (ES: -1.47; CI 95%: -2.84, -0.10; P = 0.03); self-assessment resulted not significantly in favor of SOVTEs (VHI/VRQoL: ES -0.23; CI 95% -1.14, 0.69; P = 0.63 and VTDS/VDSI: ES -4.85, CI 95% -25.13, 15.42; P = 0.64).

CONCLUSION

results obtained showed that voice therapy based on SOVTEs is not to consider significantly superior if compared to other treatments, even if a favorable trend was detected and should be taken into consideration. Further high-quality RCTs on specific SOVTEs are recommended to produce better-quality evidence.

A Comparison of the Effects of Phonation into a Positive Expiratory Pressure Device and Silicone Tube in Water on the Vocal Mechanism

OBJECTIVES

Positive expiratory pressure (PEP) devices have become an additional therapeutic approach for treating voice disorders. Similar to water resistance therapy (WRT), phonation in a PEP device introduces a secondary source of vibration within the vocal tract. This investigation aimed to compare the effects of phonation using a PEP device and silicone tube phonation (STP) commonly used in WRT on the vocal mechanism during phonation.

METHODS

Three normophonic subjects participated in the study. High-speed videoendoscopy, pressure, airflow, electroglottography, and acoustic recordings were collected.

RESULTS

The results demonstrated that phonation using both the PEP device and silicone tube induced alterations in glottal behavior. The PEP device produced more pronounced and consistent pressure oscillations, impacting the glottal cycle and influencing parameters including contact quotient (CQ), fundamental frequency, glottal area, pressure, and airflow. The regular vibratory mechanism of the PEP device systematically modified the glottal cycle. In STP, regular bubbling at lower depths of submersion produced higher CQ values, supporting the efficacy of deep bubbling exercises for inducing glottal adduction.

CONCLUSIONS

The findings suggest that phonation using PEP devices has a more pronounced impact on the vocal tract and glottis. It also provides a stronger massage effect that directly affects the glottal source. Phonation with a silicone tube produces similar results, although to a lesser extent and with lower regularity. These findings offer guidance in the selection of voice therapy devices.

An eclectic Voice Therapy Program for the Treatment of Hyperfunctional Voice Disorders (HFVD)

PURPOSE

An eclectic voice therapy program includes sequenced and structured set of exercises combining direct and indirect intervention methods. Tailor-made exercise prescription with specific cultural adaptations are needed to provide a holistic change to voice quality.1 This study detailed the construction of an exercise prescription for participants with hyperfunctional voice disorder [HFVD] in the Indian context.

METHOD

The exercise program was developed based on literature related to vocal therapy approaches and delivery methods. Adaptations were introduced to a selected set of exercises. Five voice experts verified the exercises and their prescription for content and feasibility of use in the Indian context. Modification suggested by the experts were included for framing the final version of the exercise program. This structured therapy program was planned for 6 weeks (30 minutes duration/session offered individually twice per week, with a gap of two days between sessions in a week) with the goals to improve voice quality, flexibility, and endurance while speaking. Five participants with HFVD partook in the study for pilot testing. Stroboscopy, perceptual voice analysis, Dysphonia Severity Index (DSI) and Vocal Fatigue Index in Tamil (VFI-T) were used to report the therapy outcomes. Participants' report on the learning process and generalization of the program were documented. Wilcoxon-signed rank test was used to test the pre-post outcome measures.

RESULTS

An eclectic voice therapy program, i.e., Comprehensive Voice Habilitation Program [CVHP] was constructed and it included vocal hygiene instructions, warm-up & cool-down, easy onset, resonant voice, and carry over exercises. Participants completed the program in 14-18 sessions (over 7 to 9 weeks of therapy). All participants showed significant changes in vocal fold movement patterns, reduction in ventricular hyperadduction, overall grade of voice quality, DSI and VFI-T. Participants reported that pictorial illustrations, feedback, and monitoring sheets were useful in learning the exercises.

CONCLUSION

CVHP showed significant change in the voice-related outcome measures and was a viable program for treating HFVD.

[Efficacy of Novafon Local Vibration Voice Therapy and Water Resistance Therapy: a meta-analysis]

BACKGROUND

Treatment approaches for voice therapy are diverse and two treatment approaches in voice therapy with assistive devices will be evaluated and compared for efficacy. Evaluations of the treatment effects of different approaches are important for clinical consultation and evidence-based practice.

AIM

To evaluate the efficacy of Novafon Local Vibration Voice Therapy (NLVVT) and Water Resistance Therapy (WRT) using Voice Handicap Index (VHI).

DESIGN

Systematic literature search and meta-analysis with random effects model.

DATA SOURCES

The analysis of two databases (MEDLINE and CENTRAL) and a manual search from inception to September 19th 2021.

STUDY SELECTION

Any clinical trial with case series in a pre-post design written in English or German that tested the efficacy of NLVVT or WRT using VHI (functional [F], physical [P], and emotional [E] aspects, and total score [T]) in adult voice patients with an organic or functional voice disorder was considered.

RESULTS

Five eligible studies were identified (NLVVT n= 22; WRT n= 42). Both treatment approaches showed highly significant improvement in all aspects of the VHI (p-values< 0.01). In direct comparison, NLVVT achieved significantly higher improvements in VHI-T, VHI-F and VHI-E than WRT (p-values< 0.01). Comparable improvement was received in VHI-P (p= 0.28).

CONCLUSION

NLVVT and WRT are effective treatments for voice disorders related to the subjective evaluation of a voice disorder. In direct comparison, NLVVT achieved higher improvements than WRT in most VHI aspects.

High-Speed Image Analysis Comparing Loading of Vocal Folds During Coughing and Phonation: A Case Study

PURPOSE

Coughing is related to voice problems, since it involves firm glottal closure, fast glottal opening, and high subglottic pressure and flow rate. In this study, the glottal area variation and movements of laryngeal structures during coughing and phonation are compared.

METHODS

High-speed laryngoscopy recordings were made of a normophonic male participant with a healthy larynx producing a neutral vowel and coughing. Oral air pressure was registered in a mouthpiece, through which an endoscope was inserted into the pharynx. Electroglottography, acoustic, and pressure signals were recorded simultaneously. The glottal width variation at the membranous and cartilaginous parts of the glottis was derived from the high-speed images, and the strong vibration of the false vocal folds was also registered.

RESULTS

In coughing, compared to ordinary vowel phonation in nearly the same sound pressure level (93-94 dB_6cm), the glottal width was 25% larger at the middle of the vocal folds, the maximum glottal opening velocity was 39% higher, and the maximum glottal width declination rate during glottal closing was up to three times higher. The maximum acceleration was 40% higher, and the maximum deceleration was 47% higher. Fundamental frequency f₀ was the highest (ca. 400 Hz) at the beginning of the first phase of a typical coughing process. During the last part of the coughing process, f₀ decreased from ca. 250 Hz to ca. 85 Hz at the phonation offset.

CONCLUSIONS

The remarkable increase in maximum glottal width declination rate implies much higher vocal fold loading in coughing compared to phonation.

Immediate effects of straw phonation in air or water on the laryngeal function and configuration of female speech-language pathology students visualised with strobovideolaryngoscopy: A randomised controlled trial

BACKGROUND

A promising way to obtain vocal economy and efficiency is by semi-occluding the vocal tract while phonating. Current knowledge about the immediate effects of semi-occluded vocal tract (SOVT) phonation on the laryngeal function and configuration is based mainly on computer modelling or excised larynges studies. In in vivo SOVT studies, electroglottography (EGG) has been the most commonly used laryngeal outcome, showing contradictory results between studies. Therefore, exploring these aspects by direct visualisation of the human larynx during SOVT phonation using strobovideolaryngoscopy (SVL) is needed.

AIMS

The aim of this study was to investigate and compare the immediate effects of straw phonation (SP) in air, SP in 2 cm water, and SP in 5 cm water (with stirring straws), on the laryngeal function and configuration of a homogeneous group of vocally healthy female speech-language pathology students, visualised with flexible SVL.

METHODS & PROCEDURE

A randomised controlled trial was used. Fifty-two female speech-language pathology students (mean age: 18.7 years, SD: 0.6) were assigned randomly to one of three experimental groups or a control group: (1) SP in air, (2) SP in 2 cm water, (3) SP in 5 cm water or (4) [u] phonation with similar soft onset and slightly pursed lips as in SP but without a straw (control group). The participants underwent flexible SVL during habitual [u] phonation, followed by the specific SOVT exercise of their group assignment. All video samples were evaluated randomly and blindly by two experienced investigators using the Voice-Vibratory Assessment with Laryngeal Imaging (VALI) rating form, first independently and then by consensus.

OUTCOME & RESULTS

Compared to habitual phonation, the vibrational amplitude decreased during SP in 5 cm water and SP in 2 cm water, being more prominent in the first, more flow-resistant exercise. The mucosal wave also decreased during SP in 5 cm water. The anteroposterior (AP) supraglottic compression similarly increased during SP in air, SP in 2 cm water, and SP in 5 cm water. Further, a rise in mediolateral (ML) compression and a decrease in phase symmetry and regularity were found during SP in 2 cm water. A similar decrease in regularity was observed during SP in 5 cm water.

CONCLUSIONS & IMPLICATIONS

Both SP in air and SP in water cause positive immediate laryngeal effects for voice training opportunities. More AP supraglottic activity found during each SP exercise might indicate epilarynx narrowing, an economic phenomenon associated with SOVT. Immersing the straw in water additionally diminished the vibrational amplitude, lowering vocal fold impact stress and risk for phonotrauma during the exercise. The decreased regularity of the vibrational cycles during SP in water might be due to the varying back pressure created by the water bubbling. The impact of SP in water on ML supraglottic compression needs further investigation.

WHAT THIS PAPER ADDS

What is already known on the subject A promising way to obtain vocal economy and efficiency is by semi-occluding the vocal tract while phonating. Current knowledge about the immediate effects of semi-occluded vocal tract (SOVT) phonation on the laryngeal function and configuration is based mainly on computer modelling or excised larynges studies. In in vivo SOVT studies, electroglottography (EGG) has been the most commonly used laryngeal outcome, showing contradictory results between studies. Therefore, exploring these aspects by direct visualisation of the human larynx during SOVT phonation using strobovideolaryngoscopy (SVL) is needed. What this paper adds to existing knowledge Group results of the current study generally support earlier computer modelling and in vivo studies, strengthening the current SOVT knowledge. Both SP in air and SP in water cause positive immediate laryngeal effects for voice training opportunities. More anteroposterior (AP) supraglottic activity found during each SP exercise might indicate epilarynx narrowing, an economic phenomenon associated with SOVT. Immersing the straw in water additionally diminished the vibrational amplitude, lowering vocal fold impact stress and risk for phonotrauma during the exercise. The decreased regularity of the vibrational cycles during SP in water might be due to the varying back pressure created by the water bubbling. The impact of SP in water on ML supraglottic compression needs further investigation. What are the potential or actual clinical implications of this work? Current results support that both SP in air and SP in water can be useful exercises in voice training. SP in water has shown the additional gain of lowering the vibrational amplitude during the exercise, hence supporting its appropriateness for vocal warm-ups by minimising vocal fold impact stress and the risk of phonotrauma. In the future, large-scale randomised controlled trials in other subgroups of voice users, including dysphonic patients, are needed to support evidence-based practice. SVL can facilitate the search for individualised training and therapy approaches.

A Voice Rehabilitation Protocol With the Semioccluded Ventilation Mask in Subjects With Symptoms of Vocal Fatigue and Phonatory Effort

PURPOSE

The present study was designed to assess the efficacy of a six-session physiologic voice therapy program with the semioccluded ventilation mask (SOVM) in a group of subjects with voice complaints (vocal effort and fatigue).

METHODS

Thirty-four participants with functional dysphonia were randomly assigned to one of two treatment groups: (1) voice treatment with physiologic voice therapy plus vocal hygiene program (n = 17), and (2) vocal hygiene program only (n = 17). Laryngoscopic assessment was performed in all subjects to confirm laryngeal diagnosis. Before and after voice therapy, participants underwent aerodynamic assessment. The Voice Handicap Index (VHI), Vocal Tract Discomfort Scale (VTDS), and self-assessment of resonant voice were also performed. The treatment included six voice therapy sessions. For the experimental group, the exercises consisted of a sequence of seven phonatory tasks performed with the SOVM. Comparison for all variables was performed between experimental group and control group.

RESULTS

Statistical analysis showed significant improvements for experimental group for VHI (decrease), VTDS (decrease), and self-perception of resonant voice quality (increase). Significant decrease for experimental group was observed in subglottic pressure and phonation threshold pressure.

CONCLUSION

Physiologic voice therapy based on the SOVM with connected speech exercises seems to be an effective tool to improve voice in subjects diagnosed with voice complaints. Apparently, improvements are reflected in both subjective and objective outcomes. A reduction in phonatory effort and perceptual aspects of vocal fatigue are the main subjective improvements. A decrease in air pressure-related variables seems to be the most important objective change after voice therapy.

Voice Quality of Choir Singers and the Effect of a Performance on the Voice

BACKGROUND

The voice use of choir singers is understudied despite the imbalance of high vocal demands versus low vocal education, and consequently increased risk for voice problems. Also, there is a lack of information on the effects of a performance on choristers' voices. Available studies included performances of at least one hour. To date, no studies investigated the effects of a choir performance with a duration resembling vocal warm-ups.

PURPOSE

The first purpose of this study was to determine the voice quality, capacities, symptoms and voice-related quality of life of choir singers. Secondly, the effect of a short choir performance, resembling warm-up duration (15 minutes), on the choristers' voices was investigated.

METHODS

A randomized controlled trial was used. Thirty adult choir singers (25 women, 5 men; mean age: 32 years) were assigned randomly to an experimental group or a control group. Participants in the experimental group sung in choir for 15 minutes immediately after their pre voice assessment, whereas the control group was instructed to have standard voice use (one-on-one conversation with the investigator, no singing) across that time span. A second voice assessment was repeated afterwards.

RESULTS

The choir singers showed excellent voice quality and capacities with mean scores on the Dysphonia Severity Index and Acoustic Voice Quality Index of 7.5 and 2.0, respectively. Auditory-perceptually, the mean grade score was 5/100 corresponding with a normal to mildly deviant voice quality. Patient-reported outcome measures showed mean deviant scores, indicating a considerable singing voice handicap. The choir singers seem vulnerable for stress with a high occurrence rate of 76.7% (23/30). Compared with the control group, the Dysphonia Severity Index significantly improved, whereas the self-perceived presence of vocal fatigue and complaints increased after 15 minutes of choir singing. Fundamental frequency increased in both groups, being more outspoken in the experimental group.

CONCLUSIONS

Choir singers show excellent voice quality and capacities, that further improve after a short choir performance of 15 minutes. Vocal fatigue and complaints, on the other hand, already increased after that short time span. Realizing that vocal load is much higher in real-life rehearsals, competitions and performances, choristers deserve and need a qualitative voice training and a strict follow-up. Future research should focus on effective vocal warm-up and cool-down programs for this population.

Effects of Resonance Tube Voice Therapy on Parkinson's Disease: Clinical Trial

PURPOSE

To verify the effect of resonance tube voice therapy on the vocal aspects of patients with Parkinson's Disease (PD).

METHOD

Intra-subject comparative controlled clinical trial with a single group assignment. Fourteen individuals with PD (10 men, mean age 66.1 years; four women, mean age 73.75 years) received eight 45-minute sessions of voice therapy, twice a week for 4 weeks. The therapy consisted of semi-occluded vocal tract exercises - phonation method in a resonance tube (glass, 27 cm x 9 mm) in water. Tube depth in water ranged from 2 cm to 9 cm, as the difficulty in carrying out the exercises increased (usual pitch, high pitch, low pitch, ascending/descending glissandos), followed by sentence production. The assessments were made three times: at baseline (Time0), after 30 days without intervention (Time1), and 1 day after eight intervention sessions (Time2). The following aspects were assessed: vocal intensity; acoustic parameters (Smoothed Cepstral Peak Prominence - CPPs, alpha ratio, and L1-L0 difference); auditory-perceptual analysis of the overall degree of vocal quality deviation; voice symptoms (Voice Symptom Scale protocol - VoiSS) and voice-related quality of life (Voice-Related Quality of Life Protocol - V-RQOL). The results were compared at the three times of assessment Time0/Time1/Time2 using one-way repeated measures ANOVA test and Tukey test (5% significance).

RESULTS

intervention significantly increased: vocal intensity, L1-L0 value of vowel /a/ and counting, CPP value in counting, and decreased: the overall degree of vocal quality deviation in 78% of participants, the total score of VoiSS protocol, the limitation, and emotional subscales. In addition, the intervention increased the score of all the domains of V-RQOL protocol - physical, socio-emotional, and total.

CONCLUSION

Resonance tube phonation in voice therapy was effective in increasing vocal intensity and long-term acoustic parameters, the improved overall degree of vocal quality, reducing voice symptoms, and increasing voice-related quality of life in individuals with PD.

Effect of Varied Tube Phonation in Water Exercises on Nasometric and Electroglottographic parameters: Modification in Terms of Fluid Density and Tube Submerged Depth

OBJECTIVE

Within the scope of semi-occluded vocal tract exercises (SOVTEs), we aimed to examine the effects of four exercise combinations, which involved various fluid densities and tube submersion depths, on acoustic and electroglottographic (EGG) parameters.

METHODS

Four procedures (P) were applied consecutively to 30 female participants with normal voices using different tube submersion depths and fluid densities, including P1 (2 cm, water), P2 (2 cm, nectar), P3 (10 cm, water), and P4 (10 cm, nectar). Nasometric (Nasometer II model 6450) and EGG (Electroglottograph model 6103) measurements were taken before the procedures were initiated (pre-test) and at the end of each procedure. In addition, EGG measurements were taken for each procedure during the application.

RESULTS

For all three velar positions (oral passage, oro-nasal passage, nasal passage), the only procedure that caused a significant change compared to the pre-test stage in regard to nasalance score was P2 (2 cm nectar) in common. All other procedures except P1 (2 cm water) significantly increased velar closure compared to pre-test levels. However, when the differences between the exercises were examined, the least velar closure, compared to the other procedures, was obtained after P4 (10 cm nectar). While there was no significant difference between the procedures in the EGG measurements during the exercise, a significantly higher tendency to contact was observed after the procedures with a denser consistency, and an increase in the fundamental frequency (fo) values occurred in the pairwise comparisons of the procedures in the measurements after the exercises.

CONCLUSION

In SOVTEs in which water phonation is performed with a tube, the use of a fluid with a consistency denser than water can be considered a particularly promising approach. In addition, exercises performed with increasing consistencies in 2 cm depth can provide more vocal cord and velopharyngeal port closure by increasing EGG-CQ and nasalance score values. However, more care should be taken while increasing the consistency at a submersion depth of 10 cm.

Vocal tract adjustments to minimize vocal fold contact pressure during phonation

This computational study aims to identify vocal tract adjustments that minimize the peak vocal fold contact pressure during phonation and thus should be targeted in voice therapy treating phonotraumatic vocal hyperfunction. The results showed that for a given subglottal pressure, the effect of vocal tract adjustments on the peak vocal fold contact pressure was generally small except when such adjustments caused noticeable changes in the glottal flow amplitude. In this study, this occurred mainly when the lip opening was reduced and at conditions of large initial glottal angles or high subglottal pressures, which decreased the peak contact pressure but also significantly reduced the output sound pressure level (SPL). On the other hand, increasing lip opening significantly increased sound radiation efficiency from the mouth and reduced the subglottal pressure required to produce a target SPL. Because of the large effect of the subglottal pressure on the peak contact pressure, increasing lip opening thus was able to significantly reduce the peak contact pressure in voice tasks targeting a specific SPL. In contrast, the effect of pharyngeal expansion alone had only a small effect on the peak contact pressure, whether controlling for the subglottal pressure or targeting a specific SPL.

Semi-occluded vocal tract exercises in healthy young adults: Articulatory, acoustic, and aerodynamic measurements during phonation at threshold

Semi-occluded vocal tract exercises (SOVTEs) are increasingly popular as therapeutic exercises for patients with voice disorders. This popularity is reflected in the growing research literature, investigating the scientific principles underlying SOVTEs and their practical efficacy. This study examines several acoustic, articulatory, and aerodynamic variables before, during, and after short-duration (15 s) SOVTEs with a narrow tube in air. Participants were 20 healthy young adults, and all variables were measured at threshold phonation levels. Acoustic variables were measured with a microphone and a neck accelerometer, and include fundamental frequency, glottal open quotient, and vocal efficiency. Articulatory variables were measured with ultrasound, and include measures of the tongue tip, tongue dorsum, and posterior tongue height, and horizontal tongue length. Aerodynamic variables were measured with an intraoral pressure transducer and include subglottal, intraoral, and transglottal pressures. Lowering of the posterior tongue height and tongue dorsum height were observed with gender-specific small changes in the fundamental frequency, but there were no significant effects on the transglottal pressure or vocal efficiency. These findings suggest that the voices of healthy young adults already approach optimal performance, and the continued search for scientific evidence supporting SOVTEs should focus on populations with voice disorders.

Do Professionals Who Use the Voice in a Journalistic Context Benefit from Humming as a Semi-occluded Vocal Tract Exercise?

INTRODUCTION

Many vocal enhancement and rehabilitation programs for voice professionals define vocal exercises without analyzing their effects on that specific population in which they will be applied, in the established dose and often without considering the presence and absence of vocal alteration. Journalists have sought the voice clinic due to new professional vocal demands and a vocal program is being elaborated.

OBJECTIVE

To determine the immediate effect of humming in professionals with and without voice disorders who work under high vocal demand in a journalistic context.

METHOD

Thirty-six individuals who completed the Dysphonia Risk Screening Protocol and underwent voice recording participated in the study. Three speech therapists defined the presence and/or absence of vocal changes by consensus. Subsequently, five repetitions of humming were proposed; the exercises lasted five seconds each and were separated by five seconds of complete silence, and recordings were made before and after the exercise (vowel and phrase). For the pre and post comparison between the groups with and without vocal changes, acoustic measurements and spectrogram, including the classification of the signal type, were performed.

RESULTS

The sample had a similar distribution of men and women and a mean age of 39.9 years. Most of the professionals were journalists or reporters. The risk of dysphonia was high for half of the sample, and the presence of vocal changes, predominantly mild ones, was identified in 56%. After the exercise, a decrease in noise at low frequencies and an improvement in the series of harmonics and the signal type were observed in both groups; a decrease in irregularity was observed only in the participants without vocal changes.

CONCLUSION

The proposed humming exercise had an immediate positive effect on the voice of professionals working in a journalistic context, and the changes were particularly evident in aspects of the voice that were initially altered.

Relationship of Cepstral Peak Prominence-Smoothed and Long-Term Average Spectrum with Auditory–Perceptual Analysis

Cepstral peak prominence-smoothed (CPPs) and long-term average spectrum (LTAS) are robust measures that represent the glottal source and source-filter interactions, respectively. Until now, little has been known about how physiological events impact auditory–perceptual characteristics in the objective measures of CPPs and LTAS (alpha ratio; L1–L0). Thus, this paper aims to analyze the relationship between such acoustic measures and auditory–perceptual analysis and then determine which acoustic measure best represents voice quality. We analyzed 53 voice samples of vocally healthy participants (vocally healthy group-VHG) and 49 voice samples of participants with behavioral dysphonia (dysphonic group-DG). Each voice sample was composed of sustained vowel /a/ and connected speech. CPPs seem to be the best predictor of voice deviation in both studied populations because there was moderate to strong negative correlations with general degree, breathiness, roughness, and strain (auditory–perceptual parameters). Regarding L1–L0, this measure is related to breathiness (moderate negative correlations). Hence, L1–L0 provides information about air leak through closed glottis, assisting the phonatory efficiency analysis.

Vocal Fold Collision Speed in vivo: The Effect of Loudness

Mechanical impact stress on the vocal fold surface, particularly when excessive, has been postulated to cause the so-called phonotraumatic tissue lesions, such as nodules and polyps. The collision stress between the vocal folds depends on the vocal fold velocity at the time of impact. Hence this vocal fold collision speed is a relevant parameter when considering biomechanical economy of phonation, especially in voice professionals needing a louder voice than normal. Combining a precise photometric measurement of glottal area and simultaneous measurements of translaryngeal impedance (electroglottogram) for identifying the time of the maximum rate of increase of vocal fold contact allows computing the vocal fold collision speed in a wide range of loudnesses. The vocal fold collision speed is - for modal voicing - always smaller than the maximum vocal fold velocity during the closing phase, but it strongly increases with intensity. Moreover, this increase shows a biphasic pattern, with a significant enhancement from a certain value of dB on. Understanding physiological variables that influence vocal fold collision forces provides relevant insight into the pathophysiology and the prevention of voice disorders associated with phonotraumatic vocal hyperfunction.

Effects of Sixteen Month Voice Training of Student Actors Applying the Linklater Voice Method

OBJECTIVE

This study investigates the perceptual and acoustic changes in student actors' voices after 16 months of Linklater Voice training, which is a holistic method to train actors' voices.

METHODS

Eleven (n = 11) actor students' text and Voice Range Profile (VRP) recordings were analyzed pretraining and 16 months posttraining. From text readings at comfortable performance loudness, both perceptual and acoustic analyses were made. Acoustic measures included sound pressure level (SPL), fundamental frequency (fo), and sound level differences between different frequency ranges derived from long-term-average spectrum. Sustained vowels [i:], [o], and [e] abstracted from the text sample were analyzed for formant frequencies F1-F4 and the frequency difference between F4 and F3. The VRP was registered to investigate SPL of the softest and loudest phonations throughout the voice range.

RESULTS

The perceived pitch range during text reading increased significantly. The acoustic result showed a strong trend toward decreasing in minimum fo, and increasing in maximum fo and fo range. The VRP showed a significant increase in the fo range and dynamics (SPL range). Perceived voice production showed a trend toward phonation balance (neither pressed-nor breathy) and darker voice color posttraining.

CONCLUSION

The perceptual and acoustic analysis of text reading and acoustic measures of VRP suggest that LV training has a positive impact on voice.

Can Straw Phonation Be Considered As Vocal Warm Up Among Speech Language Pathologists?

OBJECTIVE

Straw phonation exercises have been proved to be effective in improving voice quality among persons with voice pathology. The aim of the study was to investigate the effects of straw phonation as a warm-up exercise on maximum phonation duration, acoustic, and perceptual parameters of voice among Speech Language Pathologists.

STUDY DESIGN

The study adopted a pretest-posttest design.

MATERIALS AND METHOD

Twenty-five females with the mean age range of 20.87 ± 1.15 years participated in the study and completed a series of straw phonation exercises for three cycles. Maximum phonation duration, acoustic, and self-perceptual measures were assessed before and after the straw phonation exercises. F0, jitter, shimmer, nose to harmonic ratio, intensity, F1, F2, F3, F4, Maximum phonation duration, and the post self-perceptual measures were analyzed.

RESULTS

The results indicated a significant improvement in the F0, intensity, F1, F2, F4, Maximum phonation duration, and self-perceptual measures.

CONCLUSION

Straw phonation exercises provides an easy and effective warm up technique to improve the voice quality among Speech Language Pathologists and can be considered before conducting therapy sessions.

Novel insight into the coordination between pelvic floor muscles and the glottis through ultrasound imaging: a pilot study

INTRODUCTION

Pelvic floor physical therapists have long utilized breathing cues with exercises and are beginning to incorporate vocalization tasks. To date, there have been no publications describing pelvic floor displacement during vocalization tasks. This study is a preliminary investigation into the changes in bladder shape distortion as a proxy for pelvic floor muscle displacement during respiratory and phonatory tasks.

METHODS

Bladders were imaged using two-dimensional ultrasound in standing position. Measurement consisted of a diagonal line from the most anterior-superior aspect of the bladder to the most inferior-posterior aspect of the bladder. Length was measured at baseline and maximum distortion for each task. The first two tasks cued pelvic floor muscles to contract and then strain. Subsequent tasks only cued glottis function. A linear regression tested correlation between bladder distortion response to glottis tasks and cued pelvic floor tasks. The hypothesis was that diagonal would shorten with contraction, lengthen with strain, and follow a similar pattern seen in respiration for phonation tasks.

RESULTS

Ten asymptomatic participants (5 men, 5 women) showed bladder diagonal shortening when cuing pelvic floor contraction for all participants and lengthening for 7 of the 10 participants when cued to strain the pelvic floor. The response of bladder length change was variable for glottis tasks, trending toward lengthening and significantly different in response to contraction.

CONCLUSIONS

When cuing pelvic floor to contract, healthy individuals showed shortening of bladder length and most lengthened during strain. When cuing phonation and respiration tasks, there was a tendency toward bladder lengthening.

Inertagrams for a Variety of Semi-Occluded Vocal Tracts

Objective This investigation addressed the desirable source-airway interaction obtained with vocalization through a semi-occlusion at the mouth. The semi-occlusion was a flow-resistant tube of varying length and diameter. Method The methodology was strictly computational. Airway shapes resembling those obtained from magnetic resonance or computed tomography imaging were stylized. Supraglottal and subglottal acoustic impedances were calculated, from which inertagrams were plotted over a frequency range of 0-4000 Hz. The inertagrams predict which harmonics are likely to be strengthened. Results The combination of epilaryngeal airway narrowing and lengthening, a pharyngeal expansion, and an oral narrowing behind the tube produce the best overall inertagram for pitch glide exercises. This configuration supports harmonics of the source evenly over a range of 300-4000 Hz. Conclusions For clinical applications, theory predicts that the length of a tube or straw does not matter if the inner diameter is on the order of 3 mm or less. For wider open-ended tubes, greater length can compensate for the wider diameter for the beneficial inertance effect, but the desired steady pressure in the airways for vocal fold posturing cannot be maintained.

Oropharyngeal Geometry and the Singing Voice: Immediate Effect of Two Semi-Occluded Vocal Tract Exercises

PURPOSE

The aim of this study was to verify the immediate effect of a flexible resonance tube in water and of lip trill on oropharyngeal geometry and vocal acoustic parameters of singers without vocal symptoms.

METHODS

Twenty-two adult singers participated in the study. They had an average age of 27 (±4.8) years. Participants were split into two groups: a group composed of 12 singers who performed the flexible resonance tube (FRT) exercise and a group of 10 singers who performed the Lip Trill technique (LTT). Acoustic pharyngometry and acoustic analysis of the voice were used to assess oropharyngeal geometry before and after the exercises.

RESULTS

After performing the techniques, the vocal tract length was longer in the group that performed the FRT, compared to the one that performed the LTT. In the acoustic evaluation, there was an improvement in the glottal to noise excitation ratio and a decrease in noise in the group of singers who performed the LTT. In the analysis by sex men had a longer oral cavity compared to women and after application of the techniques greater volume of the vocal tract.

CONCLUSION

There was variation in the oropharyngeal geometry with the FRT, while the LTT had a positive effect on the vocal acoustic parameters related to glottal noise.

Revisiting Sustained Phonation Time of /s/, /z/, and /a/

PURPOSE

Research studies of maximum phonation time, have questioned its validity and value as a tool to assess laryngeal competence. This study proposes a fresh look at phonation time, from a different perspective. The interrelationships of the durations between semiocclusion vs. open vocal tract (/s/-/z/ vs. /a/) and voiced vs voiceless (/z/-/a/ vs. /s/) sound are examined to determine whether this approach might provide additional clinical insight into the respiratory phonatory efficiency of patients.

METHODS

Comfortable sustained phonation time of /s/, /z/ and /a/ was collected as part of the voice evaluation of patients referred by laryngologists for voice therapy. Inclusionary criteria: male and female subjects 19 years of age or older. Exclusionary criteria: autoimmune disorders, malignancies, major pulmonary/respiratory disorders.

RESULTS

A total of 218 patients (150 females and 68 males) mean age of 53.6 met all the criteria. Means, standard deviations and t test were conducted to determine whether significant differences existed. t test results indicate significance between s/z P = 0.002 and z/a P = 0.004 for females but only slight significance in s/a P = 0.03 for males. Close analysis of individual results observed four (4) different conditions or effects of fricative/semiocclusion and voicing: the close durations of the /s/ and /z/ relative to the /a/; the /z/ and /a/ are close in duration relative to the /s/; the spread of more than 5 seconds between /s/, /z/ and /a/ relative to the others; and similar duration of /s/, /z/, and /a/.

CONCLUSION

Significant differences exist in the durations of comfortable phonation time of sustained /s/ and /z/ and /a/ thought to be related to effects of semiocclusion, fricative consonants, and voicing. Phonation time should be seen not only in terms of duration, but the interplay of the phonemic qualities of the sounds as they relate of laryngeal efficiency.

Resonance Effects and the Vocalization of Speech

Studies of the respiratory and laryngeal actions required for phonation are central to our understanding of both voice and voice disorders. The purpose of the present article is to highlight complementary insights about voice that have come from the study of vocal tract resonance effects.

Effects of Varying Lengths and Diameters During Straw Phonation on an Excised Canine Model

OBJECTIVE/BACKGROUND

Straw phonation, a well-established method of vocal exercise, started over 100 years ago. However, some of the most basic questions about best practices remain including the ideal extension length and the ideal restriction (semiocclusion) diameter. This study aims to help answer these questions by looking at both separately, with all other variables controlled.

METHODS

Four (4) straws with lengths of 5, 25, 50, and 75 centimeters and 4 restrictions with diameters of 3, 9, 15, and 21 mm were tested, separately. They were attached to the end of a simulated vocal tract which was then affixed to an excised canine larynx. Airflow was increased until the larynges achieved self-sustained phonation then aerodynamic, acoustic, and electroglottographic data were collected.

RESULTS

There was a significant decrease in the phonation threshold pressure using the 5 and 25 cm straw lengths and the 9 and 15 mm restrictions. The phonation threshold flow and contact quotient saw insignificant changes, except in the case of the 3 mm restriction.

DISCUSSION

It is theorized that the increased inertive reactance helps to decrease phonation threshold pressure. By controlling for all other variables, the effects of the length or diameter of the straw can be analyzed in isolation. These results narrow the significant range of lengths and diameters used in straw phonation.

Experimental and Computational Modeling of the Effects of Voice Therapy Using Tubes

Purpose Phonations into a tube with the distal end either in the air or submerged in water are used for voice therapy. This study explores the effective mechanisms of these therapy methods. Method The study applied a physical model complemented by calculations from a computational model, and the results were compared to those that have been reported for humans. The effects of tube phonation on vocal tract resonances and oral pressure variation were studied. The relationships of transglottic pressure variation in time P_trans ( t) versus glottal area variation in time GA( t) were constructed. Results The physical model revealed that, for the phonation on [u:] vowel through a glass resonance tube ending in the air, the 1st formant frequency ( F₁ ) decreased by 67%, from 315 Hz to 105 Hz, thus slightly above the fundamental frequency ( F₀ ) that was set to 90-94 Hz . For phonation through the tube into water, F₁ decreased by 91%-92%, reaching 26-28 Hz, and the water bubbling frequency F_b ≅ 19-24 Hz was just below F₁ . The relationships of P_trans ( t) versus GA( t) clearly differentiate vowel phonation from both therapy methods, and show a physical background for voice therapy with tubes. It is shown that comparable results have been measured in humans during tube therapy. For the tube in air, F₁ descends closer to F₀ , whereas for the tube in water, the frequency F_b occurs close to the acoustic-mechanical resonance of the human vocal tract. Conclusion In both therapy methods, part of the airflow energy required for phonation is substituted by the acoustic energy utilizing the 1st acoustic resonance. Thus, less flow energy is needed for vocal fold vibration, which results in improved vocal efficiency. The effect can be stronger in water resistance therapy if the frequency F_b approaches the acoustic-mechanical resonance of the vocal tract, while simultaneously F₀ is voluntarily changed close to F_1.

Vocal tract shape and acoustic adjustments of children during phonation into narrow flow-resistant tubes

The goal of the study is to quantify the salient vocal tract acoustic, subglottal acoustic, and vocal tract physiological characteristics during phonation into a narrow flow-resistant tube with 2.53 mm inner diameter and 124 mm length in typically developing vocally healthy children using simultaneous microphone, accelerometer, and 3D/4D ultrasound recordings. Acoustic measurements included fundamental frequency (f_o), first formant frequency (F₁), second formant frequency (F₂), first subglottal resonance (F_Sg1), and peak-to-peak amplitude ratio (P_vt:P_sg). Physiological measurements included posterior tongue height (D1), tongue dorsum height (D2), tongue tip height (D3), tongue length (D4), oral cavity width (D5), hyoid elevation (D6), pharynx width (D7). All measurements were made on eight boys and ten girls (6-9 years) during sustained /o:/ production at typical pitch and loudness, with and without flow-resistant tube. Phonation with the flow-resistant tube resulted in a significant decrease in F₁, F₂, and P_vt:P_sg and a significant increase in D2, D3, and F_Sg1. A statistically significant gender effect was observed for D1, with D1 higher in boys. These findings agree well with reported findings from adults, suggesting common acoustic and articulatory mechanisms for narrow flow-resistant tube phonation. Theoretical implications of the findings are discussed.

Water Resistance Therapy as Vocal Warm-Up Method in Contemporary Commercial Music Singers

BACKGROUND/AIMS

Although water resistance therapy (WRT) has been widely used in voice training, no data are supporting the effectiveness of WRT as vocal warm-up for singers. The present study aimed to determine the effects of WRT as a vocal warm-up method in contemporary commercial music (CCM) singers.

METHODS

Twenty-two CCM singers were randomly assigned to one of two types of 15-min vocal warm-up: open vocal tract (OVT) warm-up and WRT. Self-perceived resonant voice quality and aerodynamic, electroglottographic, and acoustic measures were assessed before, immediately after vocal warm-up, and after 40 min of vocal loading.

RESULTS

Significant results were found immediately after vocal warm-up. Subglottic pressure and inspiratory airflow duration decreased in both groups. SPL decreased for the OVT group. No changes in SPL were found for the WRT group. Significant results were observed after vocal loading. Subglottic pressure and inspiratory airflow duration decreased for both groups after vocal loading. Expiratory airflow duration and electroglottographic contact quotient decreased for the OVT group.

CONCLUSION

Some objective data suggest that the WRT method is more effective as vocal warm-up than OVT exercises. Since outcomes in self-perceived resonant voice quality for both methods were similar but physiological effects were different, vocal warm-up strategies might produce a placebo effect.

Variation on Vocal Economy After Different Semioccluded Vocal Tract Exercises in Subjects With Normal Voice and Dysphonia

PURPOSE

The present study aimed at observing the possible differential effects of eight semioccluded vocal tract exercises (SOVTE) on vocal economy measured by the Quasi Output Cost Ratio (QOCR).

METHODS

Thirty-six participants were included in this study. They were divided into two groups: an experimental group of subjects diagnosed with mild hyperfunctional dysphonia (n = 17) and a control group of vocally healthy subjects (n = 19). Participants were required to randomly select and produce a series of three SOVTE from a list of eight exercises. The electroglottographic based measure QOCR was used to calculate the vocal economy before and after each voice exercise.

RESULTS

Significant differences were found when comparing pre and poststages regardless of the vocal condition (normal voice or dysphonia) or the specific SOVTE used. Moreover, when individually comparing the effect of each SOVTE, only tube in water (10 cm) showed significant differences between pre and postconditions (QOCR values were higher after exercises).

CONCLUSION

In general, semioccluded vocal tract exercises tend to increase vocal economy regardless the vocal condition (normal voice or dysphonia) or the specific SOVTE used. Phonation into a tube submerged deep into water promoted the highest increase in vocal economy. An increased acoustic output, nonproportional increase in vocal folds adduction and an effortless voice production would cause this increase in vocal economy after water resistance therapy.

Immediate Effects of the Semi-Occluded Ventilation Mask on Subjects Diagnosed With Functional Dysphonia and Subjects With Normal Voices

PURPOSE

The present study was designed to assess the immediate effects of the semi-occluded ventilation mask (SOVM) in subjects with functional dysphonia and subjects with normal voice.

METHODS

Sixty-four participants were included in this study (48 women and 16 men). Thirty-one of them were diagnosed with functional dysphonia and 33 with normal voice. All subjects were randomly assigned to one of two conditions: an experimental condition using the SOVM (n = 33) and a control condition with participants not using the SOVM (n = 31). Thus, within both conditions, participants could be either dysphonic or normal-voiced. This produced a total of four different groups: (1) subjects with normal voice with SOVM (n = 17), (2) subjects with normal voice without SOVM (n = 16), (3) dysphonic subjects with SOVM (n = 16), and (4) dysphonic subjects without SOVM (n = 15). All participants underwent aerodynamic, electroglottographic (EGG), and acoustic assessments, and were also asked to assess their own voice, before and after voice exercises.

RESULTS

Significant differences were found for aerodynamic, EGG, and acoustic variables when comparing SOVM conditions (dysphonic and normal) against control. Cepstral peak prominence and EGG contact quotient showed an increase among dysphonic participants with SOVM. L1-L0 showed an increase for all participants in SOVM condition (dysphonic and normal). Self-perceived resonant voice quality showed an increase for both groups in SOVM condition. Glottal airflow showed a decrease for the dysphonic participants in SOVM condition. Phonation threshold pressure and subglottic pressure showed a decrease for both groups in SOVM condition.

CONCLUSION

The present study suggests that immediate positive effect could be produced by connected speech phonatory tasks using the SOVM in both dysphonic subjects and subjects with normal voice, the change being greater among the former. SOVM seems to promote an easy voice production and a more efficient phonation.

Effects of Voice Therapy Using the Lip Trill Technique in Patients With Glottal Gap

OBJECTIVES

Lip trills are widely used as a voice warm-up technique among singers. However, little is known about the effects of lip trills in cases of voice disorders. We examined the therapeutic effects of lip trills in patients with glottal gap.

METHODS

Patients with glottal gap were classified into three groups according to the type of gap: gap-only, gap with muscle tension dysphonia (MTD), and a sulcus vocalis group. Patients underwent perceptual, acoustic/aerodynamic analyses, stroboscopic evaluations, and subjective analyses using a questionnaire before and after lip trills. The results were analyzed before and after trills and according to and between the groups.

RESULTS

The results in 42 patients were analyzed. Most of the parameters were improved and glottal gap was significantly reduced after trills in all patients. In the gap-only group (n = 19), most of the parameters showed improvement and were within the respective normal ranges, and glottal gap was improved after trills. In the MTD group (n = 13), although many parameters were improved, the improvement was not as prominent as in the gap-only group. In the sulcus vocalis group (n = 10), only some of the parameters were improved and the improvement in glottal gap was limited.

CONCLUSIONS

Lip trills were an effective treatment for glottal gap. The therapeutic effect was prominent in the gap-only group, followed by the MTD and sulcus vocalis groups. Trills can be used as an adjuvant treatment option in voice therapy in cases of various voice disorders.