The Effects of Respiratory Lung Volume Training on Primary Muscle Tension Dysphonia

Objective/Background: Respiratory and laryngeal physiologic abnormalities characterize primary muscle tension dysphonia (pMTD), the most common voice disorder represented in voice clinics. Speech breathing patterns of people with pMTD include low levels of lung volume initiation and termination, with associated increased laryngeal constriction, decreased airflow, higher laryngeal position, and strained voice quality. Respiratory Lung Volume Training (RLVT) is a novel treatment that trains higher levels of lung volume during speaking for increased respiratory-laryngeal efficiency. The purpose of this study is to present respiratory, acoustic, and perceptual outcomes of this study.

Methods/Design: A randomized controlled trial (RCT) was implemented to determine the effects of RLVT on speech breathing and voice outcomes. Twenty-five participants with pMTD have been enrolled in this study to date. Participants meet multiple inclusion and exclusion criteria such as: diagnosis of MTD without laryngeal pathology, patterns of supraglottal hyperfunction on laryngoscopy, and measurable acoustic dysphonia at the time of assessment. Participants were randomly assigned to one of two conditions: 1) RLVT involving six 1-hour training sessions 1xweek with real-time visual biofeedback of lung volume levels using InductoTrace, or 2) a control condition using sham Expiratory Muscle Strength Training devices with no resistive load, also conducted over six 1-hour training sessions 1xweek. Respiratory, acoustic, and self-perceived voice handicap outcome measures were gathered in two pre-training and two post-training assessments, with long-term outcomes for RLVT assessed 3 and 6 months after training.

Results/Conclusions: Data analysis for this RCT project is ongoing, with all outcomes assessed by researchers blind to timepoint, condition and participant. Normalized lung volume initiation and termination levels, lung volume excursion, and airflow expenditure per syllable will be presented to objectively characterize speech breathing outcomes for RLVT as compared to the control (sham) condition. The Cepstral Spectral Index of Dysphonia and Cepstral Peak Prominence measures will provide objective acoustic outcomes, while the Voice Handicap Index-10 will demonstrate change in self-perceived impact of the voice disorder. This study advances the state of evidence for treatment of pMTD through a controlled trial with multidimensional and impactful outcomes.

This research is funded by National Institutes of Health, NIDCD, R15DC018132