Preliminary Effects of Respiratory Lung Volume Training (RLVT) on Hyolaryngeal Kinematics in People With Primary Muscle Tension Dysphonia.

Abstract

Objectives: The purpose of this preliminary study was to determine the effects of a novel respiratory-based intervention on hyolaryngeal kinematics in people with primary muscle tension dysphonia (pMTD) using ultrasonography and acoustic measures.

Method: Pretraining to post-training changes in hyolaryngeal kinematics were studied for 11 participants with pMTD using ultrasonography to objectively measure and compare the relative positions of the hyoid bone and thyroid cartilage before and after treatment. Displacement of the hyoid bone and thyroid cartilage was measured during sustained phonation of the vowel /ɑ/, before and after completion of Respiratory Lung Volume Training (RLVT), which trains the use of higher speech lung volume initiation and termination levels while implementing real-time visual biofeedback. Hyolaryngeal position was determined from still frames extracted from ultrasound video recordings, with measures normalized to reflect change from rest during voicing for each participant. The associations between hyolaryngeal kinematics and acoustic measures of voice were also investigated.

Results: Thyroid-to-hyoid displacement during voicing was significantly lower after completion of RLVT. There were no differences in hyoid-to-mandible displacement during voicing when comparing pretraining to post-training timepoints. Moderate-to-strong associations between thyroid-to-hyoid displacement and acoustic voice measures were identified for one or more speaking contexts.

Conclusions: Laryngeal elevation during voicing appears to be reduced after completion of RLVT in people with pMTD. Mechanical and functional interactions of the respiratory and laryngeal subsystems likely contributed to this kinematic change and the associations between laryngeal kinematics and acoustic voice features. Ultrasonography-based anatomic displacement measurements may provide an objective and sensitive method for determining treatment-related change in hyolaryngeal kinematics.