The Dysphonia Severity Index as a Mediator for the Relationship Between the Vocal Fatigue Index and the Voice-Related Quality of Life Among Elementary Teachers with Voice Complaint.

INTRODUCTION: The multi-causal nature of voice disorders is required to be evaluated systematically and in different ways to determine the exact nature of the disorder. Given the importance of voice for teachers, the present study was designed to investigate the causal relationship between vocal fatigue index (VFI) and the voice-related quality of life (VRQOL) with the mediating role of the dysphonia severity index (DSI) among teachers with voice complaints. METHOD: This analytical and non-interventional study examined 57 male and 122 female teachers with voice complaint. The study used DSI, VRQOL and VFI. Acoustic data were extracted using Praat software, and statistical analysis was performed using SPSS. Direct and indirect path testing of the proposed research model was performed using path analysis and bootstrapping, respectively. RESULTS: Model fit indices showed that the proposed model is data fit (CFI = 0.998, GFI = 0.996, RMSEA = 0.072). Moreover, all subtests of the VFI had a significant direct relationship with VRQOL. The DSI, measured using the proposed model, does not have a significant relationship with VRQOL. Therefore, the indirect path of the present model (including tiredness of voice to VRQOL through DSI, physical discomfort to VRQOL through DSI and the improvement of symptoms with rest to VRQOL through DSI) did not show a significant relationship. CONCLUSION: The vocal fatigue directly affects VRQOL. However, it does not affect it indirectly through DSI. Therefore, it can be concluded that although DSI and VRQOL are correlated, they do not have a causal relationship and DSI, as an acoustic parameter, cannot be an appropriate mediator for the relationship between the VFI and VRQOL.

The Relationship Between Dysphonia Severity Index and Voice-Related Quality of Life in the Elementary School Teachers with Voice Complaint.

INTRODUCTION: Teachers are one of the largest groups of professional voice users who are highly dependent on their voice in their working environment using their voice as a primary tool for their profession. Thus, they are at high risk of voice disorders. Since voice disorders are multi-causal in nature, it is necessary to evaluate them systematically and in different ways to determine the exact nature of the disorder. Therefore, in this study, the relationship between Voice-Related Quality of Life (VRQOL) and Dysphonia Severity Index (DSI) was examined from the perspective of teachers with voice complaint. METHOD: In this study, 157 primary school teachers with voice complaint (49 males and 108 females) with an average age of 38.54 ± 9.56 years were studied using DSI and VRQOL as a self-assessment. RESULTS: The mean of VRQOL was 74.379 ± 18.95 and the mean of DSI was 1.339 ± 1.62. The results of the study showed that there is a significant positive correlation between the overall scores of DSI and VRQOL scales (r = 0.545, P < 0.001). CONCLUSION: This study showed that a low dysphonia severity index, reflecting poor laryngeal function, is associated with lower voice-related quality of life. Therefore, accurate and timely assessment of the DSI in teachers can prevent the occurrence and/or progression of voice disorder and, consequently, prevent reducing the voice-related quality of life in teachers.