A Proof-of-Concept Study of The Complete Vocal Technique (CVT), a pedagogic technique used for Performers, in Improving the Voice and Vocal Function in Patients with Muscle Tension Dysphonia (CVT4MDT) delivered by Telehealth: Study Protocol
Authors: McGlashan Julian , Aaen Mathias , White Anna , Sadolin Cathrine 
Published: August 2022

Abstract
Background: Muscle Tension Dysphonia (MTD) is responsible for up to 40% of patients presenting with voice and throat complaints. It is due to inefficient or ineffective voice production resulting from an imbalance in the control of the breathing mechanism, and uncontrolled constriction of the muscles in the larynx (voice box) or vocal tract (throat space above the vocal cords). Standard treatment is Voice Therapy delivered by a specialist Speech Therapist (SLT-V) often using a video link (telepractice aka telehealth). However, voice therapy has been portrayed as a “black box” and many recognised treatment regimens overlap in their treatment aims and therapeutic goals and have a poor-quality evidence base. The Complete Vocal Technique (CVT) is widely used in Europe by singers and vocal coaches. Practitioners (CVT-Ps) undergo a three-year accredited training programme, and the systematic and structured approach helps healthy singers and other performers optimise the function of the voice to produce any sound required. It also rapidly effective in performers with vocal problems, which are also mainly due to uncontrolled throat constrictions. Although there is a growing evidence base and understanding of how CVT can help singers, there is no evidence that, it can be of benefit to patients with MTD or is different from standard SLT techniques. This proof-of-concept study is designed to evaluate whether CVT can be used to help MTD patients using a multidimensional approach for assessment.Methods/design: A proof of concept study, will recruit 10 people with a clinical diagnosis of primary muscle tension dysphonia (Type I-III) with a VHI score­ >30, who meet the inclusion/exclusion criteria. Participants will have a multidimensional assessment using a range of validated and non-validated disease-specific questionnaires, statistical analysis of voice and electroglottographic (EGG) recordings and auditory-perceptual evaluations of the voice by Speech Therapy experts in Voice Disorders (SLT-V). They will then receive up to 6 video sessions of CVT-VT delivered using a video link by a CVT-P. The participants will then be reviewed back in clinic at 8 weeks and be reassessed, using further questionnaires and voice recordings. The assessors will be blinded to the testing order of the outcome measures and patients will act as their own controls. In addition, qualitative analysis of the therapy sessions will be made by direct observation of some of the CVT therapy sessions by an experienced SLT-V and review of the Therapist’s treatment log.The main objectives of this Proof-of Concept study are 1) to determine whether CVT-VT is beneficial in the treatment of patients with primary MTD; 2) to determine if and how CVT-VT differs from traditional SLT-VT methods and therefore if it could be a useful additional tool for SLT-VTs in the management of MTD; 3) whether delivery of CVT-VT via a video link is satisfactory to both patients and the CVT-P?Discussion: This study will involve a detailed assessment of the approach to therapy by the CVT-P to determine whether it leads to improvement in the presenting symptoms and voice production, whether it differs from traditional SLT-VT approaches, whether it is acceptable to patients as part of the evaluation as to whether a non-inferiority randomised controlled trial is feasible.Trial registration: The Protocol has been registered on the Clinicaltrials.gov website (NCT05365126 Unique Protocol ID: 19ET004). Registered 06 May 2022, https://beta.clinicaltrials.gov/study/NCT05365126?patient=Muscle%20Tension%20Dysphonia&locStr=Nottingham,%20UK&lat=52.9540223&lng=-1.1549892&distance=50