Toward Enhanced Voice-Related Self-Reports: Translation, Cross-Cultural Adaptation, and Validity

PURPOSE

This article provides a commentary on voice-related self-reports and presents various shortcomings endemic in the development and validation of these measures. Emphasis is placed on issues of construct validity, translation, and cross-cultural adaptation. Finally, a demonstration is provided to elucidate the importance of cross-cultural adaptation.

METHODS

An example of a voice-related self-report that lacks cross-cultural adaptation is provided, and a linguistic translation and cross-cultural adaptation process is outlined and demonstrated. A bilingual voice scientist, a bilingual speech-language pathologist (SLP), and two experts in voice-related self-reports completed a multistep linguistic translation and cross-cultural adaptation process and obtained back-translations from five SLPs native to the self-report's source culture.

RESULTS

Analyses of the back-translations demonstrated that the mean BiLingual Evaluation Understudy (BLEU) scores of the adapted items were higher overall than the back-translations of the original English items.

CONCLUSIONS

Unvalidated translations of voice-related self-reports are commonly used as a baseline to further translate the measure, and this deteriorates cross-cultural health equity. Cross-cultural adaptation is a crucial, but often overlooked process when translating and adapting self-reports. The present article calls for standardized methodologies with an emphasis on the necessity of careful translation methods and cultural adaptation processes.

Vocal Fatigue Index in Teachers Using Mokken Analysis

PURPOSE

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.

METHODS

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

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.

DISCUSSION

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.

Potential Biophysiological Mechanisms Underlying Vocal Demands and Vocal Fatigue

Patients with complaint of vocal fatigue have perceptual, acoustic, and aerodynamic outcomes that are heterogeneous in nature. One reason may be due to different underlying biophysiological mechanisms that lead to these heterogeneous clinical presentations. Five potential mechanisms are proposed: neuromuscular, metabolic, vocal tissue, afferent, and central neural. Analytical frameworks and study designs to study these mechanisms are also addressed. A better understanding of biophysiological mechanisms of vocal fatigue can improve precision of therapeutic approaches. It can also help shift management from symptom-based to etiology-focused approaches for vocal fatigue.

Laying the Groundwork to Study the Heterogeneous Nature of Vocal Fatigue

Vocal fatigue has remained an elusive construct-despite its significant impact on communication, vocation, and quality of life. Current frameworks define vocal fatigue in the context of vocal demands and vocal demand-responses. However, the impact of factors like individuals' baseline vocal fitness and perception of the demand are not well understood. What is also not well understood are the effects of specific vocal demand ingredients on an individual's vocal demand responses. Furthermore, current outcome measures utilized to capture vocal fatigue lack sensitivity and underlying mechanisms are poorly understood. These gaps have led to inconclusive next steps in how to best define, assess, monitor, and manage vocal fatigue. A conceptual framework is needed to study and better understand vocal fatigue constructs. Such a framework should consider the individual's baseline physiology, psychology, key vocal demand ingredients, and biophysiological mechanisms underlying demand responses. The objective of this paper is to help the reader better understand the complex and heterogeneous nature of vocal fatigue and its impact on reliable assessment and monitoring. Future studies will require better elucidation of vocal demand ingredients, will need more sensitive vocal demand response measures, and will need to take in to account an individual's baseline physiology and psychological factors.