An interventional study of Flow Ball Intervention and Straw Phonation Intervention in Prevention of Voice Disorders in Professional Voice Users and Treatment of Functional Voice Disorders in Professional Voice Users, sponsored by University Ghent. Recruiting at 1 site in Belgium. Open to participants aged 18 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-05-07.
Sponsored by University Ghent · Not applicable, Interventional, and Treatment
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.
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.
OBJECTIVE 1: TREATMENT
Inclusion Criteria:
Exclusion Criteria:
OBJECTIVE 2: PREVENTION
Inclusion Criteria:
Exclusion Criteria:
Behavioral: Flow Ball Intervention
Behavioral: Straw Phonation Intervention
Behavioral: Sham Intervention
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'
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'
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.
Flexible Strobovideolaryngoscopy
Laryngeal function determined with the Voice-Vibratory Assessment with Laryngeal Imaging (VALI) rating form (Poburka et al., 2017).
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
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
Time frame: 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).
Time frame: 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).
Time frame: 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).
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)
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).
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)
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)).
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)
VTDS: A lower index indicates less discomfort in the vocal tract. The index ranges from 0 to 96.
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)
VFI: A lower index indicates less vocal fatigue. The index ranges from 0 to 76.
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)
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.
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)
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.
Time frame: baseline (twice before the intervention), 3 weeks (immediately after the intervention), 3 weeks follow-up, 3 months follow-up
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