A Systematic Review of Inclusion and Exclusion Criteria in Healthy Occupational Voice Users in Human Research

Abstract

Background: The purpose of this systematic review was to examine the literature and ascertain the inclusion and exclusion criteria used for participant selection when conducting occupational vocal function research. Methods: Adhering to PRISMA systematic review methodology, studies performed on human participants, published in English, between 2018 and 2023 were included. The databases used were PubMed/MEDLINE (Ovid), APA PsychInfo, and Web of Science. Results: Seventy-one studies in total were included in this review, with 10 retrospective studies and 61 prospective studies. Of the 71 studies included, 13 were randomized control trials (RCTs), 12 were pre-post interventional studies, and the remaining 46 studies had various designs. Data extraction and analysis revealed that variables of sex and vocal heath were consistently accounted for in research, while other inclusion/exclusion variables including gender, hydration, and medication use were rarely included. Conclusion: The results of this systematic review highlight the need to consider more expansive inclusion/exclusion criteria as relates to factors that could impact vocal function in participants. Moreover, developing consistent inclusion and exclusion characteristics would provide greater support in the interpretation and generalization of study findings. Funding: The authors declare that this systematic review was conducted with no external funding or financial support.