Vocal FatigueNCT07062302
Effectiveness of Low-Level Light Therapy for Vocal Fatigue
A study testing photobiomodulation in people with Vocal Fatigue, run by Chinese University of Hong Kong at 1 site in Hong Kong.
Trial summary
The goal of this phase 2 clinical trial is to examine the effectiveness of photobiomodulation in patients with vocal fatigue. The main question it aims to answer is whether photobiomodulation is able to alleviate vocal fatigue in patients with diagnosed vocal fatigue. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Vocal Fatigue
- What is being tested?
- photobiomodulation
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 22 participants
- Where
- 1 siteHong Kong
- Study dates
- 9 Mar 2024to 12 Jun 2024
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Aged over 18 years old
- Meeting the diagnosis of vocal fatigue as per the VFI-HK
- Able to make informed consent
- Have not received any voice therapy before
Who cannot join
- History of photoallergy
- Significant medical or chronic diseases
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Preliminary Efficacy Study on the Effectiveness of Low-Level Light Therapy for Vocal Fatigue
The goal of this phase 2 clinical trial is to examine the effectiveness of photobiomodulation in patients with vocal fatigue.
The main question it aims to answer is whether photobiomodulation is able to alleviate vocal fatigue in patients with diagnosed vocal fatigue.
Participants will ask to receive photobiomodulation treatment for 12 sessions over a three week period.
Read the detailed description
Vocal fatigue is a common complaint of patients with voice disorder and is related to functional and/or organic voice disorders. Professional voice users, such as teachers and singers and actors, are particularly prone to vocal fatigue. It has been reported that vocal fatigue also associated with limitation to voice activities and participation. In patients with vocal fatigue, experience of inflammation and muscle pain are among possible symptoms and manifestations of the condition.
In literature, various definitions have been suggested for vocal fatigue. Welham and Maclagan defined vocal fatigue as the negative vocal adaptation led by prolonged use of voice, and it can consist of perceptual, acoustic or physiologic components of undesirable or unexpected functional changes in the laryngeal mechanism.
In exploring the nature of vocal fatigue, Titze capitalised on a generally recognised mechanism of muscle fatigue which comprised of a peripheral component and a central component. Specifically, for the peripheral component, fatigue may take place at the myo-neural junction, muscle membrane and endo-plasmic reticulum (i.e., the transmission mechanism) or the muscle filaments (i.e., the contractile mechanism), where depletion or accumulation of biochemical substances such as glycogen occurs.
Low-level light therapy (LLLT), also known as photobiomodulation (PBM) therapy, has been developed as a therapeutic procedure which involves the exposure to low levels of red and near infrared light to cells or tissues. It has been approved by the Food and Drug Administration (FDA) of the United States for aesthetic and medical purposes.
Ever since, it has been established as a non-invasive and safe approach for a number of medical processes, such as reducing inflammation, relieving pain, wound healing, skeletal muscle repair and treating neurological disorders. Specifically, its effectiveness on treating muscle fatigue was investigated with the focus placed on muscles such as bicep braquialis, quadriceps and orbicularis oris.
These studies utilised the feature of LLLT to interact with muscle tissues and therefore provide physiological and/or therapeutics effects to reduce muscle fatigue and enhance muscle performance. Relating this to the fatigue resulting from prolonged voice use at the laryngeal level, it is possible for LLLT to be developed as a treatment approach for vocal fatigue.
In a Phase 1 study, the potential effectiveness of using LLLT in vocal fatigue treatment by applying red or infrared Lights to healthy individuals following vocal loading tasks was explored. The authors concluded that red light might be effective in improving vocal fatigue on aspects of acoustic, aerodynamic, and self-perceptual markers.
The proposed study will be a Phase 2 behavioural study-controlled trial on the effectiveness of LLLT on treating vocal fatigue.
The primary objective of this study is to investigate the effectiveness of lower-level light therapy on reducing vocal fatigue on self-perceptual phenomena exhibited by participants, as well as acoustic and aerodynamic changes in voice.
Vocal Fatigue Index (Hong Kong-Chinese Version) (VFI(HK)) will be used as the primary outcome measurement methods. Perceptual evaluation of voice, acoustic measurement, aerodynamics evaluation (by maximum phonation time (MPT)), vocal symptoms scale and Voice Handicap Index (VHI-30) will be used as secondary outcome measurements.
The current study will be a preliminary clinical trial to identify the therapeutic efficacy of PBM on laryngeal muscles as a new treatment for patients with vocal fatigue. It could act as a pilot study and results obtained could be a foundation for Phase 3 RCT studies to investigate using LLLT to treat vocal fatigue.
- Conditions
- Vocal Fatigue
- Being tested
- photobiomodulation
- Keywords
- vocal fatigue, voice disorders, photobiomodulation, low-level light therapy
- Medical subject headings
- Voice Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
photobiomodulationDevice
Also called low level light therapy
The output of the photobiomodulation device is listed as below:
- Irradiation size: 15 cm × 10 cm
- Dual-wavelength: 660 nm + 850 nm
- Optical power density: 10 - 15 mW/cm2
- Dose density: 6J/cm2
| Study group | Role | What they receive |
|---|---|---|
| Photobiomodulation arm | Experimental | Not described Receives: Device: photobiomodulation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Vocal Fatigue Measure: Vocal Fatigue Index (VFI-HK)
The VFI(HK) contains 19 items in three domains (i) tiredness of voice and avoidance of voice use (ii) physical discomfort and (iii) improvement of symptoms after rest. All items are rated on a scale from zero (0, meaning "never") to four (4, meaning "always"). The score ranges from 0 to 76, with higher score indicating worst outcome.
Measured: This will be measured at baseline (pre-treatment) and within 2-weeks after the completion of treatment (post-treatment).
Secondary outcomes (3)
Vocal function measure: Voice Handicap Index - 30
The VHI-30 contains 30 items in three subscales, namely "Functional", "Physical " and "Emotional". All items are rated on a scale from zero (0, meaning "never") to four (4, meaning "always"). The highest possible score for the VHI-30 is therefore 129, with the higher indicating worst scores.
Measured: This will be measured at baseline (pre-treatment) and within 2-weeks after the completion of treatment (post-treatment).
Vocal Function Measure: Aerodynamic assessment
Maximum phonation time will be used as the aerodynamic measure. Maximum phonation will be measured in seconds (time), with the higher score indicated better outcome.
Measured: This will be measured at baseline (pre-treatment) and within 2-weeks after the completion of treatment (post-treatment).
Vocal Function Measures: Acoustic voice analysis
Four parameters will be measures:
(i) Jitter - Jitter represents the cycle-to-cycle variation in the fundamental frequency of the voice signal. Healthy, sustained phonation in young adults typically shows jitter values between 0.5% and 1.0%. Values above 1% may suggest dysphonia.
(ii) Shimmer: Shimmer represents the cycle-to-cycle variation in the amplitude of the voice signal. Shimmer values below 3% are generally considered normal. Higher shimmer values can indicate dysphonia.
(iii) Harmonic to noise ratio: HNR quantifies the ratio of harmonic to noise components in the voice signal. A high HNR indicates a strong presence of harmonics, which is characteristic of a clear, healthy voice. A low HNR suggests a greater proportion of noise in the voice, which is often associated with hoarseness.
(iv) CPPS: CPPS measures the prominence of the cepstral peak, which represents the periodicity in the voice signal. Lower CPPS values suggest dysphonia.
Measured: This will be measured at baseline (pre-treatment) and within 2-weeks after the completion of treatment (post-treatment).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Jul 2025
- Study start9 Mar 2024
- Primary completion12 May 2024
- Study completion12 Jun 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Vocal FatigueStudies of the same condition, open and under way.
- More trials run by Chinese University of Hong KongThe 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
- Not applicable
- Intervention model
- Single group
- Model description
- Photobiomodulation
- Masking
- None (open label)
- Enrolment
- 22 participants (actual)
Sponsor and investigators
- Lead sponsor
- Chinese University of Hong Kong
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Thomas Law, Chinese University of Hong Kong
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07062302
- Sponsor's protocol ID
- CREC2023.483
- Status last verified
- Jul 2025
- First submitted
- 24 Jun 2025
- Last updated
- 14 Jul 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: The data that support the findings of this study are available from the investigator, TL, upon reasonable request.
Publications
Moreno M, Calvache C, Cantor-Cutiva LC. Systematic Review of Literature on Prevalence of Vocal Fatigue Among Teachers. J Voice. 2025 Jan;39(1):105-112. doi: 10.1016/j.jvoice.2022.07.029. Epub 2022 Sep 20.
PubMed 36137877Welham NV, Maclagan MA. Vocal fatigue: current knowledge and future directions. J Voice. 2003 Mar;17(1):21-30. doi: 10.1016/s0892-1997(03)00033-x.
PubMed 12705816
Study at a glance
From the registry record, last updated by the sponsor on 14 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Preliminary Efficacy Study on the Effectiveness of Low-Level Light Therapy for Vocal Fatigue
- ClinicalTrials.gov ID
- NCT07062302
- Acronym / sponsor ID
- CREC2023.483
- Conditions
- Vocal Fatigue
- Keywords
- vocal fatigue, voice disorders, photobiomodulation, low-level light therapy
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 22 participants (actual)
- Lead sponsor
- Chinese University of Hong KongUniversity, hospital or other
- Study start
- 9 Mar 2024 (actual)
- Primary completion
- 12 May 2024 (actual)
- Study completion
- 12 Jun 2024 (actual)
- First posted
- 14 Jul 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 goal of this phase 2 clinical trial is to examine the effectiveness of photobiomodulation in patients with vocal fatigue.
The main question it aims to answer is whether photobiomodulation is able to alleviate vocal fatigue in patients with diagnosed vocal fatigue.
Participants will ask to receive photobiomodulation treatment for 12 sessions over a three week period.
Detailed description
Vocal fatigue is a common complaint of patients with voice disorder and is related to functional and/or organic voice disorders. Professional voice users, such as teachers and singers and actors, are particularly prone to vocal fatigue. It has been reported that vocal fatigue also associated with limitation to voice activities and participation. In patients with vocal fatigue, experience of inflammation and muscle pain are among possible symptoms and manifestations of the condition.
In literature, various definitions have been suggested for vocal fatigue. Welham and Maclagan defined vocal fatigue as the negative vocal adaptation led by prolonged use of voice, and it can consist of perceptual, acoustic or physiologic components of undesirable or unexpected functional changes in the laryngeal mechanism.
In exploring the nature of vocal fatigue, Titze capitalised on a generally recognised mechanism of muscle fatigue which comprised of a peripheral component and a central component. Specifically, for the peripheral component, fatigue may take place at the myo-neural junction, muscle membrane and endo-plasmic reticulum (i.e., the transmission mechanism) or the muscle filaments (i.e., the contractile mechanism), where depletion or accumulation of biochemical substances such as glycogen occurs.
Low-level light therapy (LLLT), also known as photobiomodulation (PBM) therapy, has been developed as a therapeutic procedure which involves the exposure to low levels of red and near infrared light to cells or tissues. It has been approved by the Food and Drug Administration (FDA) of the United States for aesthetic and medical purposes.
Ever since, it has been established as a non-invasive and safe approach for a number of medical processes, such as reducing inflammation, relieving pain, wound healing, skeletal muscle repair and treating neurological disorders. Specifically, its effectiveness on treating muscle fatigue was investigated with the focus placed on muscles such as bicep braquialis, quadriceps and orbicularis oris.
These studies utilised the feature of LLLT to interact with muscle tissues and therefore provide physiological and/or therapeutics effects to reduce muscle fatigue and enhance muscle performance. Relating this to the fatigue resulting from prolonged voice use at the laryngeal level, it is possible for LLLT to be developed as a treatment approach for vocal fatigue.
In a Phase 1 study, the potential effectiveness of using LLLT in vocal fatigue treatment by applying red or infrared Lights to healthy individuals following vocal loading tasks was explored. The authors concluded that red light might be effective in improving vocal fatigue on aspects of acoustic, aerodynamic, and self-perceptual markers.
The proposed study will be a Phase 2 behavioural study-controlled trial on the effectiveness of LLLT on treating vocal fatigue.
The primary objective of this study is to investigate the effectiveness of lower-level light therapy on reducing vocal fatigue on self-perceptual phenomena exhibited by participants, as well as acoustic and aerodynamic changes in voice.
Vocal Fatigue Index (Hong Kong-Chinese Version) (VFI(HK)) will be used as the primary outcome measurement methods. Perceptual evaluation of voice, acoustic measurement, aerodynamics evaluation (by maximum phonation time (MPT)), vocal symptoms scale and Voice Handicap Index (VHI-30) will be used as secondary outcome measurements.
The current study will be a preliminary clinical trial to identify the therapeutic efficacy of PBM on laryngeal muscles as a new treatment for patients with vocal fatigue. It could act as a pilot study and results obtained could be a foundation for Phase 3 RCT studies to investigate using LLLT to treat vocal fatigue.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- Photobiomodulation
| Arm | Type | Receives |
|---|---|---|
| Photobiomodulation arm | Experimental | Device: photobiomodulation |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Aged over 18 years old
- Meeting the diagnosis of vocal fatigue as per the VFI-HK
- Able to make informed consent
- Have not received any voice therapy before
Key exclusion criteria (2 listed)
- History of photoallergy
- Significant medical or chronic diseases
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 |
|---|---|---|
| photobiomodulationAlso: low level light therapyThe output of the photobiomodulation device is listed as below: * Irradiation size: 15 cm × 10 cm * Dual-wavelength: 660 nm + 850 nm * Optical power density: 10 - 15 mW/cm2 * Dose density: 6J/cm2 | Device | Photobiomodulation arm |
Primary outcome
Vocal Fatigue Measure: Vocal Fatigue Index (VFI-HK)
Time frame: This will be measured at baseline (pre-treatment) and within 2-weeks after the completion of treatment (post-treatment).
The VFI(HK) contains 19 items in three domains (i) tiredness of voice and avoidance of voice use (ii) physical discomfort and (iii) improvement of symptoms after rest. All items are rated on a scale from zero (0, meaning "never") to four (4, meaning "always"). The score ranges from 0 to 76, with higher score indicating worst outcome.
3 secondary outcomes
Vocal function measure: Voice Handicap Index - 30
Time frame: This will be measured at baseline (pre-treatment) and within 2-weeks after the completion of treatment (post-treatment).
Vocal Function Measure: Aerodynamic assessment
Time frame: This will be measured at baseline (pre-treatment) and within 2-weeks after the completion of treatment (post-treatment).
Vocal Function Measures: Acoustic voice analysis
Time frame: This will be measured at baseline (pre-treatment) and within 2-weeks after the completion of treatment (post-treatment).
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Jul 2025.
- Background: PubMed 36137877Moreno M, Calvache C, Cantor-Cutiva LC. Systematic Review of Literature on Prevalence of Vocal Fatigue Among Teachers. J Voice. 2025 Jan;39(1):105-112. doi: 10.1016/j.jvoice.2022.07.029. Epub 2022 Sep 20.
- Background: PubMed 12705816Welham NV, Maclagan MA. Vocal fatigue: current knowledge and future directions. J Voice. 2003 Mar;17(1):21-30. doi: 10.1016/s0892-1997(03)00033-x.
- Individual participant dataSharing planned: Yes. The data that support the findings of this study are available from the investigator, TL, upon reasonable request.
Related trials for Vocal Fatigue
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Recruiting
Brain and Voice Signatures in Teachers
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing photobiomodulation in people with Vocal Fatigue, run by Chinese University of Hong Kong at 1 site in Hong Kong.
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 4 inclusion and 2 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: finished, as of the sponsor's last update on 14 Jul 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 Hong Kong. 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. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Vocal Fatigue Measure: Vocal Fatigue Index (VFI-HK) (time frame: This will be measured at baseline (pre-treatment) and within 2-weeks after the completion of treatment (post-treatment).). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07062302, which also lists 2 linked publications.
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 14 Jul 2025.