Prevention of Voice Disorders in Professional Voice UsersNCT06960772
Efficacy of Flow Ball Phonation in Professional Voice Users
A study testing Flow Ball Intervention and Straw Phonation Intervention in people with Prevention of Voice Disorders in Professional Voice Users and Treatment of Functional Voice Disorders in Professional Voice Users, run by University Ghent at 1 site in Belgium.
Trial summary
The aim of this study is to investigate the effects of flow ball phonation on the voice of professional voice users and elite vocal performers, both with and without functional voice disorders. Read more about this study
- Who is it for?
- Ages 18 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Prevention of Voice Disorders in Professional Voice Users, Treatment of Functional Voice Disorders in Professional Voice Users
- What is being tested?
- Flow Ball Intervention and Straw Phonation Intervention
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 144 participants
- Where
- 1 siteBelgium
- Study dates
- 8 May 2025to 30 Sep 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- All genders
- All ethnicities
- 18 - 60 years
- Diagnosis of a functional voice disorder
- Professional voice users
- All genders
Show all 9Show fewer
- All ethnicities
- 18 - 60 years
- Professional voice users
Who cannot join
- Diagnosis of an organic voice disorder
- Current participation in voice therapy
- Previous phonosurgical interventions
- Pregnancy
- Smoking
- Nasal or ear diseases
Show all 15Show fewer
- Neurological disorders
- OBJECTIVE 2: PREVENTION
- Current or previous diagnosis of a voice disorder
- Current or previous participation in voice therapy
- Previous phonosurgical interventions
- Pregnancy
- Smoking
- Nasal or ear diseases
- Neurological disorders
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Belgium1 site, 1 recruiting
- Recruiting
Ghent University
Ghent, East-Flanders, 9000
Casey Dewanckele, +32491547192, casey.dewanckele@ugent.be
Evelien D'haeseleer
About this study
The aim of this study is to investigate the effects of flow ball phonation on the voice of professional voice users and elite vocal performers, both with and without functional voice disorders. Given the substantial vocal demands inherent to this population and their reliance on the voice for occupational purposes, this intervention may represent a valuable approach for the prevention and/or treatment voice disorders.
Read the detailed description
Background. Due to the high vocal demands, professional voice users (e.g. teachers) and elite vocal performers (e.g. singers) are risk populations for developing voice disorders. High-quality voice research in these vulnerable populations is highly needed for effective and efficient treatment and prevention of voice disorders. The flow ball (FB) is a promising innovative voice therapy device to perform semi-occluded vocal tract exercises (SOVTE) with the extra advantage of providing real-time visual feedback of the airflow. Despite this important advantage, strong efficacy studies of an FB intervention program are lacking.
Objective. To investigate the immediate-, short- and long-term effects of an SOVTE intervention with the FB on the phonation of professional voice users with (treatment) and without (prevention) voice disorders and to compare it with the 'treatment as usual' straw phonation (SP) and a sham condition, using a longitudinal randomized sham-controlled trial (RCT).
Methods. Subjects will be randomly assigned into an FB group, an SP group or a control (sham) group. They will receive a short-term intensive voice intervention of 3 weeks, combining both guided therapy/training sessions and independent practice at home. A flexible strobovideolaryngoscopy and a multidimensional voice assessment will be performed by assessors blinded to group allocation and study phase. Assessments will be performed two times before the intervention (pre 1 and pre 2), immediately after the intensive intervention (post 1) and at 3 weeks (follow-up 1) and 3 months (follow-up 2) follow-up. The sham group will use the same FB device but no phonation will be involved.
- Conditions
- Prevention of Voice Disorders in Professional Voice Users, Treatment of Functional Voice Disorders in Professional Voice Users
- Being tested
- Flow Ball Intervention, Straw Phonation Intervention, Sham Intervention
- Keywords
- Flow Ball, SOVTE, professional voice users, Straw Phonation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Flow Ball InterventionBehavioural
Participants receive an intensive intervention using the Flow Ball device over 3 weeks (a total of 5 hours), consisting of weekly:
- 1 in-person guided session of 30 minutes
- 2 guided online sessions of 15 minutes each (via teleconsult)
- On the remaining 4 days of the week, participants perform independent training at home: 5 minutes, twice daily. This training is recorded using the app 'MyMedicoach'
Straw Phonation InterventionBehavioural
Participants receive an intensive intervention using a straw over 3 weeks (a total of 5 hours), consisting of weekly:
- 1 in-person guided session of 30 minutes
- 2 guided online sessions of 15 minutes each (via teleconsult)
- On the remaining 4 days of the week, participants perform independent training at home: 5 minutes, twice daily. This training is recorded using the app 'MyMedicoach'
Sham InterventionBehavioural
Participants receive an intensive intervention over 3 weeks (a total of 5 hours), consisting of weekly:
- 1 in-person guided session of 30 minutes
- 2 guided online sessions of 15 minutes each (via teleconsult)
- On the remaining 4 days of the week, participants perform independent training at home: 5 minutes, twice daily. This training is recorded using the app 'MyMedicoach' The sham intervention uses breathing exercises through the Flow Ball, no phonation will be involved.
| Study group | Role | What they receive |
|---|---|---|
| Flow Ball | Experimental | Not described Receives: Behavioral: Flow Ball Intervention |
| Straw Phonation | Experimental | Not described Receives: Behavioral: Straw Phonation Intervention |
| Sham Intervention | Sham comparator | Not described Receives: Behavioral: Sham Intervention |
What is being measured
The primary outcome is the main question the study is designed to answer.
Flexible Strobovideolaryngoscopy
Laryngeal function determined with the Voice-Vibratory Assessment with Laryngeal Imaging (VALI) rating form (Poburka et al., 2017).
Measured: baseline (before the intervention) and 3 weeks (immediately after the intervention)
Dysphonia Severity Index (DSI)
DSI: A higher index indicates a better voice quality. The index ranges from -5 to +5 for severely dysphonic to normal voices. A more negative index indicates a worse voice quality. Values > +5 are possible in subjects with excellent vocal capacities. A DSI = +1.6 is the threshold separating normophonic from dysphonic persons.
Measured: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Acoustic Voice Quality Index (AVQI)
A lower AVQI indicates a better voice quality. The index ranges from 0 to 10 for normal to severely dysphonic voices. An AVQI of 2.95 is the threshold separating normophonic from dysphonic persons.
Measured: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V)
The CAPE-V will be used to provide an auditory-perceptual evaluation of the voice quality. This visual analogue scale will examine the voice based on the parameters grade, roughness, breathiness, asthenia, strain, instability, pitch and loudness.
Measured: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Voice Handicap Index
VHI: A lower index indicates less impact of the voice impairment on the quality of life. The VHI ranges from 0 to 120.
Measured: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Secondary outcomes (10)
Maximum phonation time (MPT)
The MPT is measured using a chronometer and the best trial out of three attempts is selected for further analysis. Participants are instructed to sustain the vowel /a:/ at their habitual pitch and loudness after a maximal inspiration. Verbal encouragement is employed to maximize phonation duration
Measured: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Fundamental frequency (fo)
To assess fo participants will produce the vowel /a:/ at their habitual pitch and loudness for three seconds, following an automatic series (counting to three).
Measured: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Jitter
To assess the jitter participants will produce the vowel /a:/ at their habitual pitch and loudness for three seconds, following an automatic series (counting to three).
Measured: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Shimmer
To assess the shimmer participants will produce the vowel /a:/ at their habitual pitch and loudness for three seconds, following an automatic series (counting to three).
Measured: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Noise to Harmonics Ratio (NHR)
To assess NHR participants will produce the vowel /a:/ at their habitual pitch and loudness for three seconds, following an automatic series (counting to three).
Measured: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Voice Range Profile (VRP)
The VRP indicates the vocal capabilities by examining the range of both fundamental frequency and intensity. The participants will produce the vowel /a:/ respectively at their minimum pitch, minimum intensity, maximum pitch, and maximum intensity to determine their VRP (lowest and highest fundamental frequency (Flow, Fhigh) and lowest and highest intensity (Ilow, Ihigh)).
Measured: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Vocal Tract Discomfort Scale (VTDS)
VTDS: A lower index indicates less discomfort in the vocal tract. The index ranges from 0 to 96.
Measured: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Vocal Fatigue Index (VFI)
VFI: A lower index indicates less vocal fatigue. The index ranges from 0 to 76.
Measured: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Singing Voice Handicap Index 10 (SVHI-10)
Only used with singers. The SVHI-10-NL is used assess self-perceived voice handicap among singers with singing voice difficulties. A higher index indicates a greater perceived singing voice handicap and scores of 14 or above are considered deviant. The index ranges from 0 to 40.
Measured: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Evaluation of Ability to Sing Easily (EASE-NL)
Only used with singers. The EASE-NL is a tool to assess singer's perceptions of the current status of their singing voice. It is more sensitive to detect subtle changes of the singer's voice. A higher index indicates a more deviant score. The index ranges from 0 to 60.
Measured: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 May 2025
- Study start8 May 2025 (estimated)
- Primary completion31 Dec 2027 (estimated)
- Study completion30 Sep 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Prevention of Voice Disorders in Professional Voice UsersStudies of the same condition, open and under way.
- More trials run by University GhentThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 144 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Ghent
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Evelien D'haeseleer, Principal investigator, University Ghent
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06960772
- Sponsor's protocol ID
- ONZ-2025-0017
- Status last verified
- Apr 2025
- First submitted
- 28 Apr 2025
- Last updated
- 7 May 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 7 May 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Efficacy of Flow Ball Phonation in Professional Voice Users
- ClinicalTrials.gov ID
- NCT06960772
- Acronym / sponsor ID
- ONZ-2025-0017
- Conditions
- Prevention of Voice Disorders in Professional Voice Users, Treatment of Functional Voice Disorders in Professional Voice Users
- Keywords
- Flow Ball, SOVTE, professional voice users, Straw Phonation
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 144 participants (estimated)
- Lead sponsor
- University GhentUniversity, hospital or other
- Study start
- 8 May 2025 (estimated)
- Primary completion
- 31 Dec 2027 (estimated)
- Study completion
- 30 Sep 2028 (estimated)
- First posted
- 7 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of this study is to investigate the effects of flow ball phonation on the voice of professional voice users and elite vocal performers, both with and without functional voice disorders. Given the substantial vocal demands inherent to this population and their reliance on the voice for occupational purposes, this intervention may represent a valuable approach for the prevention and/or treatment voice disorders.
Detailed description
Background. Due to the high vocal demands, professional voice users (e.g. teachers) and elite vocal performers (e.g. singers) are risk populations for developing voice disorders. High-quality voice research in these vulnerable populations is highly needed for effective and efficient treatment and prevention of voice disorders. The flow ball (FB) is a promising innovative voice therapy device to perform semi-occluded vocal tract exercises (SOVTE) with the extra advantage of providing real-time visual feedback of the airflow. Despite this important advantage, strong efficacy studies of an FB intervention program are lacking.
Objective. To investigate the immediate-, short- and long-term effects of an SOVTE intervention with the FB on the phonation of professional voice users with (treatment) and without (prevention) voice disorders and to compare it with the 'treatment as usual' straw phonation (SP) and a sham condition, using a longitudinal randomized sham-controlled trial (RCT).
Methods. Subjects will be randomly assigned into an FB group, an SP group or a control (sham) group. They will receive a short-term intensive voice intervention of 3 weeks, combining both guided therapy/training sessions and independent practice at home. A flexible strobovideolaryngoscopy and a multidimensional voice assessment will be performed by assessors blinded to group allocation and study phase. Assessments will be performed two times before the intervention (pre 1 and pre 2), immediately after the intensive intervention (post 1) and at 3 weeks (follow-up 1) and 3 months (follow-up 2) follow-up. The sham group will use the same FB device but no phonation will be involved.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Flow Ball | Experimental | Behavioral: Flow Ball Intervention |
| Straw Phonation | Experimental | Behavioral: Straw Phonation Intervention |
| Sham Intervention | Sham comparator | Behavioral: Sham Intervention |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (9 listed)
- All genders
- All ethnicities
- 18 - 60 years
- Diagnosis of a functional voice disorder
- Professional voice users
Key exclusion criteria (15 listed)
- Diagnosis of an organic voice disorder
- Current participation in voice therapy
- Previous phonosurgical interventions
- Pregnancy
- Smoking
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Flow Ball InterventionParticipants receive an intensive intervention using the Flow Ball device over 3 weeks (a total of 5 hours), consisting of weekly: * 1 in-person guided session of 30 minutes * 2 guided online sessions of 15 minutes each (via teleconsult) * On the remaining 4 days of the week, participants perform independent training at home: 5 minutes, twice daily. This training is recorded using the app 'MyMedicoach' | Behavioural | Flow Ball |
| Straw Phonation InterventionParticipants receive an intensive intervention using a straw over 3 weeks (a total of 5 hours), consisting of weekly: * 1 in-person guided session of 30 minutes * 2 guided online sessions of 15 minutes each (via teleconsult) * On the remaining 4 days of the week, participants perform independent training at home: 5 minutes, twice daily. This training is recorded using the app 'MyMedicoach' | Behavioural | Straw Phonation |
| Sham InterventionParticipants receive an intensive intervention over 3 weeks (a total of 5 hours), consisting of weekly: * 1 in-person guided session of 30 minutes * 2 guided online sessions of 15 minutes each (via teleconsult) * On the remaining 4 days of the week, participants perform independent training at home: 5 minutes, twice daily. This training is recorded using the app 'MyMedicoach' The sham intervention uses breathing exercises through the Flow Ball, no phonation will be involved. | Behavioural | Sham Intervention |
Primary outcome
Flexible Strobovideolaryngoscopy
Time frame: baseline (before the intervention) and 3 weeks (immediately after the intervention)
Laryngeal function determined with the Voice-Vibratory Assessment with Laryngeal Imaging (VALI) rating form (Poburka et al., 2017).
Dysphonia Severity Index (DSI)
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
DSI: A higher index indicates a better voice quality. The index ranges from -5 to +5 for severely dysphonic to normal voices. A more negative index indicates a worse voice quality. Values > +5 are possible in subjects with excellent vocal capacities. A DSI = +1.6 is the threshold separating normophonic from dysphonic persons.
Acoustic Voice Quality Index (AVQI)
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
A lower AVQI indicates a better voice quality. The index ranges from 0 to 10 for normal to severely dysphonic voices. An AVQI of 2.95 is the threshold separating normophonic from dysphonic persons.
Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V)
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
The CAPE-V will be used to provide an auditory-perceptual evaluation of the voice quality. This visual analogue scale will examine the voice based on the parameters grade, roughness, breathiness, asthenia, strain, instability, pitch and loudness.
Voice Handicap Index
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
VHI: A lower index indicates less impact of the voice impairment on the quality of life. The VHI ranges from 0 to 120.
10 secondary outcomes
Maximum phonation time (MPT)
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Fundamental frequency (fo)
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Jitter
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Shimmer
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Noise to Harmonics Ratio (NHR)
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Voice Range Profile (VRP)
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Vocal Tract Discomfort Scale (VTDS)
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Vocal Fatigue Index (VFI)
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Singing Voice Handicap Index 10 (SVHI-10)
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Evaluation of Ability to Sing Easily (EASE-NL)
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 May 2025.
- Individual participant dataSharing planned: No
Related trials for Prevention of Voice Disorders in Professional Voice Users
Not yet recruiting
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Voice Fatigue, Voice Disorder
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Evelien D'haeseleer principal investigator
University Ghent
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Flow Ball Intervention and Straw Phonation Intervention in people with Prevention of Voice Disorders in Professional Voice Users and Treatment of Functional Voice Disorders in Professional Voice Users, run by University Ghent at 1 site in Belgium.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 7 May 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Belgium. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Casey Dewanckele (+32491547192, casey.dewanckele@ugent.be), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Flexible Strobovideolaryngoscopy (time frame: baseline (before the intervention) and 3 weeks (immediately after the intervention)). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 May 2025.