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.

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

Adverse event data were collected over the period in which each participant completed baseline testing, training, and post-testing, or 8 weeks total.