Applicability of the vocal tract discomfort (VTD) scale in evaluating the effects of voice therapy of occupational voice disorders.
Occupational voice disorders are characterized by rich symptomatology, which is dominated by symptoms by the vocal tract discomfort. Therefore, in the management it is important to consider these subjective complaints. The aim of the study was to assess the usefulness of using the vocal tract discomfort scale (VTD) in evaluating the effects of rehabilitation concerning occupational dysphonia. The study included 55 teachers (mean age: 47.2) with occupational dysphonia diagnosed by means of videostroboscopy. The test battery covered also: voice self-assessment according to voice handicap index (VHI), perceptual GRBAS scale and the new VTD scale. Each subject underwent intensive rehabilitation, including voice training and voice hygiene education. The post-therapy examination was conducted using the above-mentioned methods. Comparing the results obtained in the preliminary and the control test a significant post-therapy improvement (p = 0.000) was discovered in relation to the general outcome of the symptoms in the VTD scale-- assessed both as for the frequency subscale (24.7 points vs. 10 points) and the severity subscale (25.5 points vs. 10 points). A positive significant effect of the treatment was also observed in the voice VHI disability index (p < 0.05) and in perceptual voice evaluation, using the GRBAS scale (p < 0.05). In addition, the study revealed a high coefficient of correlation (r) between the subscales of the VTD, both in the preliminary examination (r = 0.934) and the control one (r = 0.935). The vocal tract discomfort scale (VTD) seems to be a valuable tool, useful in monitoring the progress in the treatment of occupational voice disorders.