Cross-cultural adaptation of the Brazilian version of the Vocal Fatigue Index - VFI.

The purpose of this study was to perform the cultural adaptation of the Brazilian version of the Vocal Fatigue Index (VFI). Two Brazilian bilingual speech-language pathologists (SLP) translated the original version of the VFI in English into Portuguese. The translations were reviewed by a committee of five voice specialist SLPs resulting in the final version of the instrument. A third bilingual SLP back-translated this final version and the same committee reviewed the differences from its original version. The final Portuguese version of the VFI, as in the original English version, was answered on a categorical scale of 0-4 indicating the frequency they experience the symptoms: 0=never, 1=almost never, 2=sometimes, 3=almost always, and 4=always. For cultural equivalence of the Portuguese version, the option "not applicable" was added to the categorical scale and 20 individuals with vocal complaints and dysphonia completed the index. Questions considered "not applicable" would be disregarded from the Brazilian version of the protocol; no question had to be removed from the instrument. The Brazilian Portuguese version was entitled "Índice de Fadiga Vocal - IFV" and features 19 questions, equivalent to the original instrument. Of the 19 items, 11 were related with tiredness of voice and voice avoidance, five concerned physical discomfort associated with voicing, and three were related to improvement of symptoms with rest or lack thereof. The Brazilian version of the VFI presents cultural and linguistic equivalence to the original instrument. The IFV validation into Brazilian Portuguese is in progress.