Towards a basic protocol for functional assessment of substitution voices: preliminary results of an international trial

We performed an international trial with a newly developed multidimensional assessment protocol for substitution voices based on the European Laryngological Society protocol for ‘common dysphonia’. However, as sound production in SV is largely irregular, we needed some adaptations, in particular of the dimensions perception, acoustic analysis and visual evaluation. The protocol consisted of clinical information, the IINFVo perceptual rating scale, visual examination (level and quality of vibration), acoustic registration of vowels, vcv, cvcvcv and text (which was later analysed with the Auditory Model Based Pitch Extractor (AMPEX)), aerodynamic measurements (Vital Capacity, Maximum Phonation Time, and Maximal Intensity), and self-evaluation (of i) voice quality and ii) degree of invalidity). Six centers participated. We retained 96 suitable files (out of 102). Variance analysis demonstrates significance for i) all perceptual parameters (except for Voicing), MPT and Maximal Intensity and ii) type of surgery and/or main anatomical vibration source. There is no correlation at all between the patient’s perception of his /her disability and perceptual parameters, MPT, quality of vibration. Correlation between the acoustical analysis and the subjective rating was only moderate (Pearson < 0.62; standard deviation >1.8).