Background & Objective: Teachers, as professional voice users, are at high risk of voice disorders. The greater their dependency on voice as a means of social and professional satisfaction, the worse the effects of voice disorders on the quality of their lives. Voice complaints may have a great impact on the quality of teachers’ lives. There are no self-appraisal protocols for teachers' quality of life. Therefore, little is known about how valid the Persian version of VHI and V-RQOL scales are. It is also unknown which of the aforementioned scales best describes the effect of voice disorder on the population under investigation. As such, it is important to know to what extent the aforementioned scales correlate with each other. Therefore, the aim of this study was to calculate the correlation between total scores of the Persian versions of VHI and V-RQOL scales administered to teachers with voice disorders.
Methods: This study was a cross-sectional descriptive-analytical one. The participants were 32 female primary teachers with voice disorders recruited through available sampling. In order to confirm that the participants suffer from voice disorders, they were asked to express the sound /a/ with their habitual pitch and loudness for a period of 7 seconds. Sound samples were recorded, while environmental noise was controlled (less than 50 dB). In the next step, the acoustic parameters (F0, SD F0, NNE, HNR, Shimmer and Jitter) were investigated in a 5 second interval of recorded sound using Praat software. If the values of the acoustic parameters were higher than normal, the sample was judged as abnormal. Then the teachers with a disordered voice sample were asked to read and complete the Persian version of the VHI and V-RQOL forms carefully. The normality of data distribution was tested by using Shapiro-Wilkes test and the correlation between the total score of the two questionnaires was assessed by Pearson's correlation test.
Results: Shapiro-Wilkes test showed that the data was normally distributed. The correlation between the total score of VHI and V-RQOL was assessed using Pearson's correlation test. The results revealed a significant correlation between the overall scores of the participants on VHI and V-RQOL scales (r=-0.876, p<0.001). As the correlation was negative, it can be concluded that the higher the participants’ scores on the Voice Handicap Index, the lower their scores on Voice-Related Quality of Life scale.
Conclusion: Since a significant negative correlation exists between the scores gained by teachers with voice disorders on the VHI and V-RQOL questionnaires, it is concluded that both questionnaires measure the same feature (voice related quality of life). So, it is suggested that experts in clinical practice should use either of the two scales as they wish. In other words, there is no need to use both of them.