Validity and Reliability of Spanish Version of Two Questionnaires of Vocal Fatigue in Female Teachers

Objectives: This study aimed to determine the reliability, validity, and the specificity and sensitivity of the Spanish version of two questionnaires, the Voice Fatigue Index (VFI) and the Voice Fatigue Handicap Questionnaire (VFHQ), in female teachers, analyze the influence of the sociodemographic factors on the questionnaires, and conduct a comparative study of the psychometric characteristics of the two questionnaires on vocal fatigue (VF). Materials and Methods: The VFI and VFHQ, Spanish version, was produced following a rigorous forward and backward translation. Seventy-one female teachers were recruited to complete the VFI and VFHQ Spanish version. They also completed Voice Handicap Index-10 in its Spanish version to validate the translation of the VF questionnaires. Finally, they completed a self-elaborated questionnaire to describe the factors that influenced their vocal load and other relevant biological, personal, and occupational data. Results: The two questionnaires showed high indicators of reliability for VFI (factor 1 α = 0.92, factor 2 α = 0.85, and factor 3 α = 0.92) and for VFHQ (α = 0.95). The scores from VFI_f1, VFI_f2, and VFHQ attained high validity values in Pearson's correlation coefficient when compared to the Voice Handicap Index-10 reference questionnaire. VFI_f3 showed low validity values in Pearson's when compared to the others VFI factors (f1, f2), the VFHQ, and the Voice Handicap Index-10 reference questionnaire. Conclusions: The present study showed good reliability and validity of the VFI and VFHQ in its Spanish version. Thus, it is suggested to use the VFHQ to identify and quantify the VF handicap. To identify individuals who suffer from VF or are at high risk of VF and vocal discomfort, we recommend the application of the VFI. Based on validity results, the VFI does not appear to be a valid tool in the detection of individuals who recuperate their voice after an episode of VF.