Investigating Cultural Adaptation and Psychometric Properties of the Vocal Fatigue Index (VFI) Worldwide: A Systematic Review.

Introduction: The Vocal Fatigue Index (VFI) is a widely used self-report questionnaire that is reliable for research and clinical purposes. Several studies have adapted and validated the VFI versions in different languages using various approaches. This study evaluated the translation process, validity, and reliability of various VFI versions across different languages.

Method: This systematic review involved the authors searching the PubMed, Scopus, Web of Science, and Google Scholar databases to gather relevant data. The articles were extracted from English studies published between 2015 and 2024. After screening, the paper that met the study eligibility criteria was included. Two authors used the Critical Appraisal Skills Programme to evaluate the methodology of the papers. The review included versions of VFI that were adapted and validated for linguistic or cultural variations.

Results: The initial database contained 3294 search results. After removing duplicates, 1285 articles were analyzed. Nineteen studies were chosen following a review of their titles and abstracts. After eliminating five studies, 14 versions were selected for the final evaluation.

Discussion/conclusion: This review comprehensively understood the challenges encountered during cross-cultural adaptation and psychometric evaluation. Due to the advantageous characteristics of VFI, it has been rapidly translated into various languages since its publication. Research indicates that there was no preferred method for translation, as each study employed a distinct approach. The strong validation properties observed in various languages support the applicability of the translated versions of the VFI across diverse populations.