Efficacy of voice therapy assessed with the Voice Range Profile (Phonetogram)

Voice Range Profile (VRP), or Phonetography, is a widely used method of acoustic voice assessment: it explores and documents the extreme possibilities or capabilities of the voice by producing a chart displaying the intensity dynamics as a function of the fundamental frequency range. In the present study VRP is used for investigating the efficacy of (isolated) functional voice therapy, and for defining the best suited VRP criteria for this purpose. 30 adult voice patients with complaints of chronic dysphonia (> 4 months) fitted the acceptance--and exclusion criteria, and received functional voice therapy for 2 sessions/week during 3-6 months therapy (2x/week). VRP was performed before and after therapy, and a follow-up VRP was conducted 3 months after completion of the therapy. The parameters "softest intensity" and "VRP--area" seem the most sensitive parameters: they show an average highly significant improvement after therapy, and still an average significant improvement between the end of treatment and the follow-up measurement. For daily practice, an index (3 points-index) combining Fo-range and softest intensity is proposed.