Objective: Muscle Tension Dysphonia is a common voice disorder that different methods are used to treat it. Circumlaryngeal Manual Therapy (CMT) is one of the treatments used for muscle tension. Of course, recently, the treatment of this type of dysphonia has tended to use newer methods, one of which is the use of infrared light therapy. The aim of this study was to evaluate the effect of combining this therapy with CMT to these patients using acoustic features, vocal tract discomfort scale, visual analog scale, and palpation rating scale.
Methods / Design: To answer the research question, an interventional study of the type of randomized controlled clinical trial with a pre-test and post-test design was designed. Patients were randomly assigned into two groups of manual therapy (eleven people, seven females) and manual therapy combined with infrared light therapy (eleven people, eight females). These two groups of patients were evaluated at four time points, including the first session before the intervention (evaluation), the first session after the intervention, the eighth session and two weeks after that (follow-up period). Each of these patients received eight treatment sessions. If the variables had a normal distribution, Generalized Estimating Equations (GEE) test was used, and if they had a non-normal distribution, Wilcoxon and McNemar tests were used. The significance level was _ = 0.05.
Results: Combining infrared light therapy with manual therapy compared to the use of manual therapy alone, showed significant changes in the variables related to the evaluations (including acoustic evaluations, vocal tract discomfort scale, visual analog scale and palpation rating scale).
Conclusions: The results of this study showed the positive and significant effects of combining infrared light therapy with CMT on the voice characteristics of MTD patients. Therefore, it seems that infrared light therapy can be a useful pre-treatment for the treatment of patients with voice disorders. Combining this pre-treatment with manual therapy can result in muscle relaxation and faster treatment.