Reliability of the Italian INFVo scale and correlations with objective measures and VHI scores

The objective of this study was to evaluate the reliability of the INFVo scale and its relationship with objective measures and VHI scores in 40 native Italian-speaking patients with substitution voice. The maximum phonation time (MPT), diadochokinesis (DDK) of the three syllabic sequence [pa/ta/ka], reading of a passage and a single word repetition test were recorded. Each patient completed the Italian version of the VHI. Three speech-language pathologists blindly rated the recordings using the auditory perceptual INFVo scale; one listened and assessed the voice recording twice. The INFVo intra- and inter-rater reliability reached good values. Strong to moderate correlations between the INFVo scale scores and MPT, DDK, distortions in the repetition test, speech rate during reading and the functional subscale of the VHI were found. In conclusion, the INFVo scale is a reliable tool and can be recommended for the perceptual assessment of substitution voices in Italian speaking patients.