Vocal Fatigue Index in Teachers Using Mokken Analysis

Abstract

Vocal fatigue (VF) is a primary vocal symptom experienced by professional voice users, such as teachers, whose voice is an occupational tool. The study determines the utilization of the Vocal Fatigue Index (VFI), a 19-item scale in identifying symptoms of VF and its severity in teachers. Using responses of 695 teachers who completed the VFI, Mokken scaling was conducted on the items to identify the experiences of VF and its associated hierarchical nature of VF symptoms in teachers. Mokken scaling was completed on a total of four groups: (a) Total teachers group, (b) No VF group, (c) Low VF group, and (d) High VF group. Results revealed differences in item hierarchies between total teachers and across the separate groups of VF severity. Item hierarchy for teachers highlighted items from physical discomfort at the mild end of the hierarchy to items from symptom improvement with rest at the severe end of the hierarchy. Items related to avoidance presented as a separate scale for teachers presenting with high VF. Mokken scaling in teachers provides insight into the underlying complexity of the experience of VF symptoms and reliance on differential behavioral strategies in its management, suggesting the heterogenous nature of latent trait for VF in this specific population.