Review of the impact of voice training on the vocal quality of professional voice users: implications for vocal health and recommendations for further research.

OBJECTIVE: To review the current published available research into the impact of voice training on the vocal quality of professional voice users, to provide implications for vocal health and recommendations for further research. DESIGN: Literature review with a systematic approach. METHODS: A systematic search of the literature was conducted using electronic databases and the following defined search terms: occupational voice or occupational dysphonia or voice and occupational safety and health. To obtain the comprehensive relevant literature, no studies were excluded on the basis of study design. In total, 10 studies that investigated the impact of a voice training intervention on the vocal quality of professional voice users as a potential prevention strategy for voice disorders were selected for this review. RESULTS: The 10 studies ranged in design from observational to randomized controlled trials with mainly small sample sizes (N = 11-60). Nine studies showed that voice training significantly (P < 0.05) improved at least one voice-related measurement from the several investigated from baseline. Five studies reported that voice training significantly (P < 0.05) improved at least one measurement compared with no training. CONCLUSIONS: Findings indicate that there is no conclusive evidence that voice training improves the vocal effectiveness of professional voice users, as a result of a range of methodological limitations of the included studies. However, some studies did show that voice training significantly improved the knowledge, awareness, and quality of voice. Therefore, there is a need for robust research to empirically confirm this, with implications for vocal health, and occupational safety and health policies.

Occupational voice demands and their impact on the call-centre industry.

BACKGROUND: Within the last decade there has been a growth in the call-centre industry in the UK, with a growing awareness of the voice as an important tool for successful communication. Occupational voice problems such as occupational dysphonia, in a business which relies on healthy, effective voice as the primary professional communication tool, may threaten working ability and occupational health and safety of workers. While previous studies of telephone call-agents have reported a range of voice symptoms and functional vocal health problems, there have been no studies investigating the use and impact of vocal performance in the communication industry within the UK. This study aims to address a significant gap in the evidence-base of occupational health and safety research. The objectives of the study are: 1. to investigate the work context and vocal communication demands for call-agents; 2. to evaluate call-agents' vocal health, awareness and performance; and 3. to identify key risks and training needs for employees and employers within call-centres. METHODS AND DESIGN: This is an occupational epidemiological study, which plans to recruit call-centres throughout the UK and Ireland. Data collection will consist of three components: 1. interviews with managers from each participating call-centre to assess their communication and training needs; 2. an online biopsychosocial questionnaire will be administered to investigate the work environment and vocal demands of call-agents; and 3. voice acoustic measurements of a random sample of participants using the Multi-dimensional Voice Program (MDVP). Qualitative content analysis from the interviews will identify underlying themes and issues. A multivariate analysis approach will be adopted using Structural Equation Modelling (SEM), to develop voice measurement models in determining the construct validity of potential factors contributing to occupational dysphonia. Quantitative data will be analysed using SPSS version 15. Ethical approval is granted for this study from the School of Communication, University of Ulster. DISCUSSION: The results from this study will provide the missing element of voice-based evidence, by appraising the interactional dimensions of vocal health and communicative performance. This information will be used to inform training for call-agents and to contribute to health policies within the workplace, in order to enhance vocal health.