The Effect of Vocal Hygiene Education Programs on Voice Quality in Professional Voice Users: A Systematic Review.

Purpose: This study aimed to critically appraise recent peer-reviewed scientific evidence on the effect of vocal hygiene education on voice quality and function directly and indirectly measured by auditory-perceptual, acoustic, and self-report measures in professional voice users.
Method: A systematic review was conducted utilizing the Preferred Reporting Items for Systematic review and Meta-Analyses Protocols (PRISMA-P) guidelines. Five databases were searched using the keywords "vocal hygiene," "vocal hygiene education," "vocal health," "vocal quality," and "voice quality" with Boolean phrases "AND" and "OR." Twenty-three studies that met the eligibility criteria were included. Scoring was based on the American Speech-Language-Hearing Association's levels of evidence and quality indicators, as well as the Newcastle-Ottawa Scale for assessing the risk of bias.
Results: Four studies (17%) linked low awareness of vocal hygiene or insufficient vocal hygiene education to self-reported acute and chronic voice symptoms, as well as a greater perception of voice handicap among professional voice users. Numerous studies ( n = 10; 43%) showed that adequate voice training or vocal hygiene education was linked to positive voice outcomes. Six studies (6.26%), however, demonstrated that vocal hygiene education is more effective when combined with direct voice therapy. When vocal hygiene education is presented in isolation, the superiority of a direct voice therapy approach, with or without vocal hygiene education, is seen over a vocal hygiene education program alone (indirect treatment).
Conclusions: Recent literature demonstrates mixed results obtained through auditory-perceptual, acoustic, and self-rating measures on the effects of vocal hygiene instruction on vocal quality and function in professional voice users. However, the compelling positive outcomes presented do warrant implementation of vocal hygiene education programs in combination with direct voice therapy for professional voice users.