Effects of External Vibration on Voice Quality in Muscle Tension Dysphonia Patients and Classically Trained Singers

Overview

Muscle tension dysphonia (MTD) is a disabling voice disorder which causes severe voice change, neck pain, and voice fatigue. Current therapy modalities to treat these disorders include multiple visits to a qualified speech language pathologist (SLP) for rehabilitation with voice exercises and focused laryngeal/neck massage. Access to these services is difficult with long waitlists and often not covered by current public health insurance or locally available to many patients in Ontario. The goal of this study is to demonstrate a reduction in symptoms and improvement in vocal function by applying an external vibration device to key sites (e.g. jaw, neck, skull base) commonly identified as a source of abnormal muscle tension and injury in certain voice disorders, specifically MTD. This study will also investigate the effect of external vibration on the voice quality in classically trained singers (CTSs). Certain desirable acoustic qualities in a singers' voice are only accessible when the larynx and its extrinsic muscles are in a relaxed state. Muscle misuse and vocal strain are common problems in performers, which can result in conditions that require surgery and speech therapy, and may lead to a loss of income. Similar to vocal warm up exercises which contribute to the prevention of vocal injury, external vibration is expected to improve muscle perfusion in an acute setting and may have a direct effect on vocal fold cover viscosity. Both study groups will be randomized to receive either the external vibration device or a sham device. The sham device looks identical to the experimental device but has the vibration component removed.

Muscle tension dysphonia is primarily treated with voice therapy with a qualified SLP. One of the key therapy tools for MTD is laryngeal extrinsic muscle massage along with voice and respiratory exercises. Access to these specialized services is difficult due to limited expertise and travel distance. The goal of this study is to demonstrate a reduction in symptoms and improvement in vocal function by applying an external vibration device to key sites (e.g. jaw, neck, skull base) commonly identified as a source of abnormal muscle tension and injury in certain voice disorders, specifically MTD. If the study shows a demonstrable benefit, patients would be trained to self administer the treatment along with a home program of therapy exercises. This novel therapy would improve delivery of care and allow speech therapy services to be more widely accessible with reduced number of therapy sessions required. The potential long term effects would be to decrease wait times to access these specialized services and lessen the need for return visits due to symptom recurrence. The second part of this study is to investigate the effect of external vibration on the voice quality in CTSs. Certain desirable acoustic qualities in a singers' voice are only accessible when the larynx and its extrinsic muscles are in a relaxed state. Muscle misuse and vocal strain are common problems in performers, which can result in conditions that require surgery and speech therapy, and may lead to a loss of income. Similar to vocal warm up exercises which contribute to the prevention of vocal injury, external vibration is expected to improve muscle perfusion in an acute setting and may have a direct effect on vocal fold cover viscosity.