Psychometric Characteristics of Different Versions of Vocal Tract Discomfort (VTD) Scale: A Systematic Review

BACKGROUND: This review compare different Vocal Tract Discomfort (VTD) versions. This comparison is based on their validity and reliability parameters in the translation and adaptation process. We aimed to prepare numerical evidence to prove the validity of this easy screening tool. VTD is able to perform an accurate diagnosis of voice discomforts, particularly in primary stages. METHODS: Articles were selected from databases including Google Scholar, PubMed, Science Direct and Scopus. Our relevant papers were gathered by searching the phrase: VTD in titles, abstracts, and keys. Studies not followed an adaptive procedure were excluded. Based on the selection criteria, out of 23 collected articles, eight were studied in this review. RESULTS: Standard psychometric protocol steps were followed in all selected articles and simultaneously high reliability and validity were reported in their translation procedure. Such analogous results may confirm the efficacy of this research tool. CONCLUSION: This review affirms VTD, perceptual patient-based scale, as a valuable evaluation tool to investigate the occurrence of voice disorders. Based on its structure and performance, VTD can work as a quick and precise source for predicting vocal discomforts. Moreover, this capability can help professional therapists to plan more efficient treatment procedures. The other important advantage of VTD is its diagnostic and prognostic capacity to inform patients about their current and future conditions so that they would be motivated to follow treatment procedures more consistently.