Cross-cultural adaptation, validation, and cutoff values of the Brazilian version of the Voice Symptom Scale-VoiSS.

OBJECTIVES

The present study sought to determine the validity, reliability, and responsiveness of the Brazilian Portuguese Voice Symptom Scale (VoiSS) and also identify characteristics of efficacy and cutoff values that discriminate dysphonic from vocally healthy individuals.

STUDY DESIGN

Cross-sectional, nonrandomized, prospective study with controls.

METHODS

Thirty hundred subjects (160 with dysphonia and 140 without dysphonia) completed the Brazilian version of the VoiSS as well as a vocal self-assessment scale using a five-point rating system (excellent, very good, good, fair, and poor).

RESULTS

The Brazilian version of VoiSS, referred to as the Escala de Sintomas Vocais (ESV), was valid, reliable, and responsive. A score of 16 was determined to be highly sensitive (100%) and specific (100%) for individuals with dysphonia.

CONCLUSIONS

The Brazilian version of VoiSS or ESV demonstrated a high degree of validity, reliability, and responsiveness with regard to differentiating aberrant vocal function and was valuable as an instrument to quantify the response to treatment in patients with dysphonia. The cutoff value that discriminates individuals with dysphonia from vocally healthy subjects was 16.