An interventional study of Device: hyperbaric oxygen therapy in Vocal Cord Strain (Disorder), sponsored by Assaf-Harofeh Medical Center. Recruiting at 1 site in Israel. Open to participants aged 18 Years to 70 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-16.
Sponsored by Assaf-Harofeh Medical Center · Not applicable, Interventional, and Treatment
The aim of the current study is to evaluate the Impact of Hyperbaric Oxygen Therapy on Vocal Performance in Professional Singers
Professional singers frequently face occupational risks that affect the health and function of their vocal folds. Vocal fold pathologies such as vocal folds edema, nodules, polyps, laryngitis, and muscle tension dysphonia are common among singers and can lead to significant alterations in voice quality and performance endurance. Traditional therapeutic approaches often include voice rest, vocal training, and in some cases, pharmacological interventions or surgery. However, these methods can be either only partially effective, require extended downtime, which is impractical for professional singers, or expose the singer to potentially significant side effects as in the case of the commonly used steroids interventions.
Hyperbaric oxygen therapy (HBOT) has emerged as a potential innovative treatment for enhancing tissue healing and managing various medical conditions. Research has demonstrated HBOT\'s efficacy in enhancing tissue repair and modulating inflammatory responses, making it a compelling candidate for treating vocal fold injuries. Despite its potential, the application of HBOT in improving vocal fold function has not been thoroughly investigated. This study aims to fill this gap by evaluating the effectiveness of HBOT in enhancing vocal performance, through a prospective, randomized, controlled design. This research will provide robust evidence of the potential benefits of HBOT, offering an alternative or adjunct therapy that could improve the management of vocal health in the singing profession.
In the following text, we will review the physiology of the vocal folds, the common pathophysiology in professional singers, and the physiological effect of the new protocols of HBOT.
Assaf-Harofeh Medical Center is the lead sponsor of 267 studies on the registry; 43 are open to participants now.
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The HBOT protocol consists of 40 daily sessions, five times per week, within a three months' period. Then there will be a follow-up period for 3 months without any investigated intervention. each session lasting 90 minutes, of 100% oxygen at 2 ATA and 5-minute air breaks every 20 minutes.
Device: Device: hyperbaric oxygen therapy
The HBOT protocol consists of 40 daily sessions, five times per week, each session lasting 90 minutes. Investigational product: Multiplace hyperbaric oxygen chamber (Haux, Germany) located at the Sagol Center for Hyperbaric Medicine and Research, Shamir (Assaf-Harofeh) Medical Center, Israel.
Vocal performance tests
The primary endpoint will be based on the evaluation of the voice recordings using the following measurement :Fundamental frequency (F0) : Mean F0 = average pitch across the sample Maximum F0 = highest pitch reached Minimum F0 = lowest pitch reached Units Hertz (Hz)
Time frame: Change from Baseline immediately after the intervention
Stroboscopy
Participants would be asked to have larynx anatomic and functional evaluation performed by an otolaryngologist, using a laryngeal stroboscopy system. evaluation of vocal fold vibration and reveals subtle vocal fold pathologies, such as vocal fold scars which could be easily missed by using constant light laryngoscopy.
Time frame: only at baseline and after the last HBOT sessions
singing ability Questionnaire
The Singers Voice Handicap Index (Singers VHI) is a self-assessment questionnaire used to evaluate the impact of voice disorders on the participant quality of life. It consists of 36 questions scored on a scale from 0 to 4 , that assess various aspects of vocal function (physical, functional, and emotional)
Time frame: Change from Baseline immediately after the intervention
Short form health survey (sf-36)
Assessment of health-related quality of life with the SF-36 Health Survey. Quality of life questionnaire, scale of 0-100, higher score means better outcome
Time frame: Change from Baseline immediately after the intervention
Vocal Range
The span between the lowest and highest producible pitches. The span between the lowest and highest producible pitches.
Time frame: Change from Baseline immediately after the intervention
Jitter (cycle-to-cycle variations in pitch)
Small cycle-to-cycle irregularities in frequency/pitch during vocal fold vibration. Measurements Needed Duration/frequency of consecutive vibratory cycles Variation between one cycle and the next Units Percent (%) Microseconds (µs)
Time frame: Change from Baseline immediately after the intervention
Shimmer (cycle-to-cycle variations in amplitude)
Cycle-to-cycle irregularity in loudness/amplitude. Measurements Needed Amplitude of each glottal cycle Differences between adjacent cycles Units Percent (%) Decibels (dB)
Time frame: Change from Baseline immediately after the intervention
Harmonics-to-Noise Ratio (HNR)
Ratio of periodic harmonic energy (clear vocal tone) to aperiodic noise energy (breathiness/roughness). Measurements Needed Harmonic signal energy Noise component energy Units Decibels (dB) Meaning Higher HNR = clearer/healthier voice Lower HNR = noisier/hoarser voice
Time frame: Change from Baseline immediately after the intervention
Maximum Phonation Time (MPT)
Longest duration a person can sustain a vowel (usually /a/) on one breath. Measurements Needed Deep inhalation Sustain vowel at comfortable pitch/loudness Measure time until phonation stops Units Seconds
Time frame: Change from Baseline immediately after the intervention
NeuroTrax - optional
only If the participants agree to the extended evaluation. Computerized cognitive evaluation battery. Cognitive function will be evaluated using the Mindstreams cognitive health assessment (Mindstreams). This assessment comprises of several cognitive tests that evaluate various aspects of brain capabilities. each outcome parameter will be normalized and fit to an IQ-like scale (mean=100, STD=15), according to the participants' age and education.
Time frame: Change from Baseline immediately after the intervention
CANTAB cognitive battery test - optional
only If the participants agree to the extended evaluation. computerized cognitive evaluation battery test, divided into 2 tasks: 1- Multitasking test (MTT)- attention, reaction time and executive functions, Multitasking test Incongruency cost - A higher incongruency cost indicates that the subjects takes longer to process conflicting information. 2-Paired associated learning (PAL)- visual memory and new learning, PAL Number of Patterns Reached (0-8), PAL Total Errors (Adjusted) (0-64), PAL Total Attempts(0-64).
Time frame: Change from Baseline immediately after the intervention
MRI Imaging - optional
only If the participants agree to the extended evaluation. At each of the evaluations, patients will undergo structural and functional MRI scanning. Images will be acquired on MAGNETOM Vida 3T Scanner, configured with a 64-channel receiver head coils (Siemens Healthcare, Erlangen, Germany) at Shamir medical center radiology
Time frame: Change from Baseline immediately after the intervention
brain imaging ( FMRI in rest ) - Optional
only If the participants agree to the extended evaluation. Resting state fMRI(rsfMRI or R-fMRI)- a method of functional brain imaging that can be used to evaluate regional interactions that occur when a subject is not performing an explicit task. This resting brain activity is observed through changes in blood flow in the brain which creates what is referred to as a blood-oxygen-level dependent (BOLD) signal that can be measured using functional Magnetic Resonance Imaging (fMRI).
Time frame: Change from Baseline immediately after the intervention
electrical brain activity - optional
only If the participants agree to the extended evaluation. Quantitative EEG (qEEG) including task related EEG analysis. EEG analysis for each state within subject and between subjects will include frequency analysis (peak frequency and relative power), oscillations (proportions of the different bands alpha, beta, theta, delta activities) and power spectra distribution.
Time frame: Change from Baseline immediately after the intervention
Sleep Analysis - optional
only If the participants agree to the extended evaluation. Changes in sleep patterns will be measured using the Pittsburgh sleep quality index (PSQI). The PSQI assesses the quality and patterns of sleep in adults. Items are rated using a 0 to 3 scale. The component scores are summed to produce a global score (range 0 to 21). Higher scores indicate worse sleep quality.
Time frame: Change from Baseline immediately after the intervention
Ratings of Vocal Quality (GRBAS) by Speech-Language Pathologists / ENTs
GRBAS is a standardized perceptual rating scale used by trained clinicians (such as Speech-Language Pathology profession professionals or Otolaryngology profession physicians) to judge overall voice quality. GRBAS stands for: G = Grade (overall severity of dysphonia) R = Roughness (irregular/harsh quality) B = Breathiness (audible air escape) A = Asthenia (weakness/lack of power) S = Strain (pressed/tense quality) Measurements Needed Voice Sample Collection Clinician listens to one or more of: Sustained vowel (e.g., /a/) Reading passage Conversational speech Singing sample (if relevant) Rater Scoring Each GRBAS component is rated: 0 = Normal 1. = Slight 2. = Moderate 3. = Severe. Meaning Higher scores = greater perceived vocal impairment Useful for pre/post treatment comparison Subjective but clinically valuable
Time frame: Change from Baseline immediately after the intervention
Self-Evaluation (Singers VHI)
A self-report questionnaire measuring how the singer perceives the impact of voice problems on function, emotions, and performance. Usually refers to a singer-adapted form of the Voice Handicap Index (VHI) such as the Singing Voice Handicap Index (SVHI). Measurements Needed Questionnaire Completion by Singer Respondent rates statements such as: My voice tires easily I cannot sing softly/loudly as needed My voice problem frustrates me My singing range has changed Responses are typically on a Likert scale: 0 = Never 1. = Almost never 2. = Sometimes 3. = Almost always 4. = Always Output Total Score Sum of all item scores. Interpretation Lower score = fewer perceived problems Higher score = greater handicap / impact
Time frame: Change from Baseline immediately after the intervention
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