Vocal Fatigue and Its Relationship with Vocal Hygiene and Work-Related Factors in Professional and Nonprofessional Voice Users: A Multiple Linear Regression Model Study

Abstract

To investigate vocal fatigue severity between professional voice users (PVUs) and nonprofessional voice users (NPVUs), and across different levels of voice users. Also to examine the relationship between vocal hygiene and work-related factors with vocal fatigue. This is a cross-sectional descriptive study. Four hundred one individuals from different professions were included in total. Participants were divided into four levels of voice users by classification of Koufman and Isaacson. The top three levels of voice users further identified as PVU, and level 4 voice users identified as NPVU. An online questionnaire which included vocal hygiene checklist, work-related factors, and Turkish version of vocal fatigue index (VFI) was submitted by the participants. Vocal fatigue severity of PVUs were found higher than NPVUs in all VFI scores (P<0.05). Level 2 voice users were found to have more vocal fatigue severity than all other levels of voice users. Call center workers (CCWs) had the highest means of vocal fatigue severity. Based on the multiple linear regression model vocal hygiene and the number of vocal rest breaks were found to have related with vocal fatigue the most (P<0.05). There was also a relation with some VFI scores (P<0.05) with voice usage duration at work and vocal rest duration. We found no relationship between working experience and vocal fatigue. The data suggests the relation between vocal fatigue and vocal hygiene, and work-related factors explain a small proportion of the association. However, in CCWs r2 was found 0.44. The change in vocal fatigue severity did not match with Koufman and Isaacson's classification of voice users. We suggest that there may be other contributing factors to vocal fatigue than vocal hygiene, vocal rest, and voice usage duration even those factors may differ from profession to profession.