Effectiveness of a mobile phone application in managing voice health for teachers: A randomized controlled trial

Teachers are at constant risk of straining their voices due to professional demands, making them more susceptible to voice disorders and therefore increased absenteeism. A widely accessible prevention method would be beneficial, leading to the development of the ReSt mobile application. The aim of this study was to evaluate its effectiveness.

A randomized controlled trial was conducted with 399 teachers, allocating 205 participants to the training group and 194 to the control group. Over a 46-day period, participants in the training group engaged with the ReSt app. Outcomes were assessed using self-reports via the Voice Handicap Index (VHI-12) and objective evaluations employing the Dysphonia Severity Index (DSI). Additionally, app use was fully tracked using log data to gain insight into user engagement.

On average, the training resulted in substantial improvements in the DSI within the training group compared to the control group ( $\gamma =2.22,SE=0.32,p<.001$ ). No training effect was observed concerning the VHI-12 ( $\gamma =-0.39,SE=0.46,p=.388$ ). The average number of days spent opening exercises in the app was 10.57 days (SD $=$ 9.07), and time spent on exercise-related app screens averaged 2.38 hours (SD $=$ 2.79).

The app appears to have promising effects on physiological measured voice capability, but more training time may be needed to minimize the psychosocial impact of voice problems. Our results mark an important advancement in voice disorder prevention approaches, especially given previously inconclusive evidence for traditional voice training methods.