The Effects of Respiratory Training on Voice

The Effects of Respiratory-Based Treatment for Muscle Tension Dysphonia: A Randomized Controlled Trial

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT04710862

Enrollment

Registered

2021-01-15

Start date

2021-05-12

Completion date

2024-09-23

Last updated

2025-07-24

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Muscle Tension Dysphonia

Keywords

voice, voice disorder, treatment, respiratory, muscle tension dysphonia, training

Brief summary

Primary muscle tension dysphonia is a voice disorder that involves excessive and poorly coordinated muscle activity affecting multiple subsystems that are involved in speech production, in the absence of structural or neurologic abnormalities of the larynx. Primary muscle tension dysphonia (MTD) is one of the most common forms of voice disorders, accounting for at least 40% of patients seen in voice clinics. Perceptually the voice sounds hoarse and strained, with reduced loudness and pitch range, and people with MTD find speaking very effortful and fatiguing. The physiological abnormalities that characterize MTD are considered multifactorial, and include over-activity of muscles in and around the larynx, laryngeal constriction patterns, and abnormal speech breathing patterns. However, standard treatment approaches for MTD primarily address laryngeal function, including repositioning of laryngeal structures, reducing activity in the intrinsic and extrinsic laryngeal muscles, and altering vibratory patterns. Although voice improvement may follow these treatments, many people with MTD show recurrence of voice problems after only a few months, and some do not improve with treatment. These findings highlight the need for alternative treatments that address the respiratory contributions to MTD, which directly affect the phonatory system. The goal of this project is to compare the effects of two respiratory-based training conditions in people with MTD. A randomized group design will be implemented to determine the respiratory and acoustic effects of each condition. We will determine the effects of each condition immediately after and then 3 and 6 months after training completion to assess short- and long-term training effects. We propose that respiratory training will have a positive effect on related laryngeal behavior and voice. The proposed project has the potential to substantially advance the evidence-based treatment options for MTD, providing a vital step toward reducing the debilitating effects of this disorder.

Interventions

BEHAVIORALBreathing training without a device

Breathing training without a mouth device

BEHAVIORALBreathing training with a device

Breathing training with a mouth device

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Masking

DOUBLE (Subject, Outcomes Assessor)

Intervention model description

Participants will be randomly assigned to one of two conditions

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

* Ages 18 or older * Self-report of general good health other than voice disorder * Self-report of normal pulmonary function * Non-smoker status for at least the last 5 years * English as their primary language to avoid potential linguistically-based differences in acoustic measures of voice * Adequate visual acuity (with or without corrective lenses) to read basic graphs and print, as determined with visual screening * No evidence of current organic or neurologic laryngeal pathology, as assessed by nasolaryngoscopy examination and reviewed by a laryngologist * No prior surgery to the vocal folds * Do not report difficulty with swallowing * Not currently receiving voice therapy or other voice treatment that cannot be discontinued * Do not report a bilateral, severe to profound hearing loss * Willingness to be recorded for data collection that is necessary for this study * Have a confirming diagnosis of Muscle Tension Dysphonia from an otolaryngologist and speech-language pathologist * Demonstrate quantified auditory-perceptual dysphonia and acoustic dysphonia (Cepstral/Spectral Index of Dysphonia) that exceed normative values for the participant's age and sex * Based on the nasolaryngoscopy examination and assessment performed by the otolaryngologist, show one or more patterns of supraglottic activity that are consistent with adducted vocal fold hyperfunction * Show no evidence of abnormal, incomplete vocal fold closure patterns as determined on the videostroboscopy assessment (patterns of posterior glottal gaps are normal and expected) * Show no evidence of additional neurological voice disorders such as spasmodic dysphonia or vocal fold paralysis * Show elevated hyolaryngeal position that exceeds normative expectations as determined through quantitative analysis of ultrasonographic laryngeal images measuring change from rest to phonation * Demonstrate voice problems that have persisted for ≥2 months * Demonstrate self-reported increase in speaking effort * Show evidence of speech breathing abnormalities relative to accepted normative values

Exclusion criteria

* Ages 17 or younger * Self-report of major health problems * Self-report of pulmonary disease such as asthma, chronic obstructive pulmonary disease, or emphysema * Current smoker status or prior smoker status within the last 5 years * English not the primary language * Inadequate visual acuity (with corrective lenses if applicable) to read basic graphs and print as determined by failing a visual screening * Evidence of current organic or neurologic laryngeal pathology, as assessed by nasolaryngoscopy examination and reviewed by a laryngologist * Prior surgery to the vocal folds * Currently receiving voice therapy or other voice treatment that cannot be discontinued * Self-report of a bilateral, severe to profound hearing loss * Not willing to be recorded for data collection that is necessary for this study * No confirming diagnosis of Muscle Tension Dysphonia from an otolaryngologist and speech-language pathologist * Do not demonstrate quantified auditory-perceptual dysphonia and acoustic dysphonia (Cepstral/Spectral Index of Dysphonia) that exceed normative values for the participant's age and sex * Based on the nasolaryngoscopy examination and assessment performed by the otolaryngologist, do not show one or more patterns of supraglottic activity that are consistent with adducted vocal fold hyperfunction * Show evidence of abnormal, incomplete vocal fold closure patterns as determined on the videostroboscopy assessment (patterns of posterior glottal gaps are normal and expected) * Show evidence of additional neurological voice disorders such as spasmodic dysphonia or vocal fold paralysis * Do not show elevated hyolaryngeal position that exceeds normative expectations as determined through quantitative analysis of ultrasonographic laryngeal images measuring change from rest to phonation * Demonstrate voice problems that have persisted for less than 2 months * Do not demonstrate self-reported increase in speaking effort * Do not show evidence of speech breathing abnormalities relative to accepted normative values

Design outcomes

Primary

Measure	Time frame	Description
Post Training Lung Volume Termination	Assessed after completion of 6-week training period, approximately 7 weeks after baseline assessment	Average level of lung volume at which speech breaths are terminated, expressed in percent vital capacity relative to resting expiratory level.
Post Training Cepstral Peak Prominence	Assessed after completion of 6-week training period, approximately 7 weeks after baseline assessment	Average energy in first cepstral peak relative to overall cepstral energy, measured in cepstral decibels. The Cepstral Peak Prominence measure indicates the regularity, or periodicity, of the voice, and is calculated from the recorded acoustic voice signal. A low score such as 2.0 indicates lower regularity in the voice, or greater severity of voice disturbance, whereas a higher score indicates greater regularity in the voice, or less severity of voice disturbance. The values of this measure can theoretically range from zero to any positive integer value.
Post Training Cepstral/Spectral Index of Dysphonia	Assessed after completion of 6-week training period, approximately 7 weeks after baseline assessment	The Cepstral/Spectral Index of Dysphonia is a multivariate measure that indicates the acoustic severity of voice, and is calculated from the recorded acoustic voice signal. The scale generally ranges from 0 to 100, although negative values and values greater than 100 are possible. A score of zero or a low score indicates no acoustic dysphonia (no voice abnormality) or little dysphonia, whereas a high score or score of 100 indicates high severity or maximal severity of acoustic dysphonia.
Post Training Lung Volume Initiation	Assessed after completion of 6-week training period, approximately 7 weeks after baseline assessment	Average level of lung volume at which speech breaths are initiated, expressed in percent vital capacity relative to resting expiratory level.
Post Training Lung Volume Excursion	Assessed after completion of 6-week training period, approximately 7 weeks after baseline assessment	Average level of lung volume at which speech breaths are terminated, expressed in percent vital capacity.

Secondary

Measure	Time frame	Description
Post Training Voice Handicap Index-10	Assessed after completion of 6-week training period, approximately 7 weeks after baseline assessment	The Voice Handicap Index-10 is a questionnaire in which the participant rates the amount of handicap they feel from their voice disorder. Each of 10 questions is rated between a score of 0 (no handicap) to 4 (extreme handicap). Total scores on this questionnaire can range between 0 to 40, with a low score indicating that the participant feels low amounts of handicap or life impact from their voice disorder, whereas a high score indicates that a participant feels high amounts of handicap from their voice disorder.
Post Training Auditory-Perceptual Overall Severity of Voice Disorder	Assessed after completion of 6-week training period, approximately 7 weeks after baseline assessment	Auditory-Perceptual Overall Voice Severity is a measure that indicates the perceptual severity of the voice, and is determined by listeners who rate the overall severity of how the voice sounds on a Visual Analog Scale that ranges from 0 to 100. A score of zero or a low score indicates no or little perceived dysphonia (voice abnormality), whereas a high score or score of 100 indicates high or maximal perceived severity of dysphonia.

Countries

United States

Participant flow

Pre-assignment details

27 participants were enrolled in the study. After initial testing to determine inclusion and exclusion criteria, 3 participants were excluded due to not meeting all inclusion/exclusion criteria. The remaining 24 participants were randomized into the two intervention groups, 12 per group.

Participants by arm

Arm	Count
Breathing Training With a Device (Sham Training as Control) Respiratory intervention delivered once a week for 6 weeks, after two initial baseline testing sessions. Participants will perform exhalation exercises through a breathing device. Homework activities will be assigned. Post-training testing sessions will also be conducted. Breathing training with a device: Breathing training with a mouth device	12
Breathing Training Without a Device (Respiratory Lung Volume Training) Respiratory intervention delivered once a week for 6 weeks, after two initial baseline testing sessions. Participants will receive training on the use of breathing techniques without a device, but with visual feedback throughout training. Homework activities will be assigned. Post-training testing sessions will also be conducted. Breathing training without a device: Breathing training without a mouth device	12
Total	24

Baseline characteristics

Characteristic	Breathing Training With a Device (Sham Training as Control)	Breathing Training Without a Device (Respiratory Lung Volume Training)	Total
Age, Continuous	60.0 years STANDARD_DEVIATION 15.4	55.4 years STANDARD_DEVIATION 12.6	58.3 years STANDARD_DEVIATION 13.9
Auditory-Perceptual Overall Voice Severity	35.16 units on a scale STANDARD_DEVIATION 24.4	30.85 units on a scale STANDARD_DEVIATION 20.71	33.01 units on a scale STANDARD_DEVIATION 22.56
Cepstral Peak Prominence	4.96 decibels (dB) STANDARD_DEVIATION 1.24	4.85 decibels (dB) STANDARD_DEVIATION 0.96	4.91 decibels (dB) STANDARD_DEVIATION 1.1
Cepstral/Spectral Index of Dysphonia	30.73 units on a scale STANDARD_DEVIATION 13.18	29.59 units on a scale STANDARD_DEVIATION 8.43	30.16 units on a scale STANDARD_DEVIATION 10.81
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants	1 Participants	1 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	12 Participants	11 Participants	23 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants	0 Participants	0 Participants
Lung Volume Excursion	20.08 % vital capacity relative to rest level STANDARD_DEVIATION 4.94	19.60 % vital capacity relative to rest level STANDARD_DEVIATION 8.04	19.84 % vital capacity relative to rest level STANDARD_DEVIATION 6.49
Lung Volume Initiation - Relative to Resting Expiratory Level	19.01 % vital capacity relative to rest level STANDARD_DEVIATION 6.11	15.05 % vital capacity relative to rest level STANDARD_DEVIATION 7	17.03 % vital capacity relative to rest level STANDARD_DEVIATION 6.56
Lung Volume Termination - Relative to Resting Expiratory Level	-1.07 % vital capacity relative to rest level STANDARD_DEVIATION 4.4	-4.55 % vital capacity relative to rest level STANDARD_DEVIATION 5.38	-2.81 % vital capacity relative to rest level STANDARD_DEVIATION 4.89
Race (NIH/OMB) American Indian or Alaska Native	0 Participants	0 Participants	0 Participants
Race (NIH/OMB) Asian	0 Participants	1 Participants	1 Participants
Race (NIH/OMB) Black or African American	0 Participants	0 Participants	0 Participants
Race (NIH/OMB) More than one race	0 Participants	0 Participants	0 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants	0 Participants	0 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants	0 Participants	0 Participants
Race (NIH/OMB) White	12 Participants	11 Participants	23 Participants
Region of Enrollment United States	12 participants	12 participants	24 participants
Sex: Female, Male Female	7 Participants	5 Participants	12 Participants
Sex: Female, Male Male	5 Participants	7 Participants	12 Participants
Speaking Effort	56.56 units on a scale STANDARD_DEVIATION 22.43	58.46 units on a scale STANDARD_DEVIATION 13.99	57.51 units on a scale STANDARD_DEVIATION 18.21
% Vital Capacity per Syllable	1.42 % vital capacity relative to rest level STANDARD_DEVIATION 0.48	1.44 % vital capacity relative to rest level STANDARD_DEVIATION 0.65	1.43 % vital capacity relative to rest level STANDARD_DEVIATION 0.57
Voice Handicap Index-10	19.96 units on a scale STANDARD_DEVIATION 6.49	19.75 units on a scale STANDARD_DEVIATION 9.33	19.86 units on a scale STANDARD_DEVIATION 7.91

Adverse events

Event type	EG000 affected / at risk	EG001 affected / at risk
deaths Total, all-cause mortality	0 / 12	0 / 12
other Total, other adverse events	0 / 12	0 / 12
serious Total, serious adverse events	0 / 12	0 / 12

Outcome results

Primary

Post Training Cepstral Peak Prominence

Average energy in first cepstral peak relative to overall cepstral energy, measured in cepstral decibels. The Cepstral Peak Prominence measure indicates the regularity, or periodicity, of the voice, and is calculated from the recorded acoustic voice signal. A low score such as 2.0 indicates lower regularity in the voice, or greater severity of voice disturbance, whereas a higher score indicates greater regularity in the voice, or less severity of voice disturbance. The values of this measure can theoretically range from zero to any positive integer value.