[Diagnosis of functional voice disorders by using the high speed recording technics].

INTRODUCTION: Malfunctions of the human voice with unknown causes are denoted by "functional voice disorders". The high speed video imaging technique (HVT) allows the recording of the oscillating vocal folds in real time. A new method is presented, describing different types of oscillation and their onset mathematically. A precise classification of the kind of functional voice disorders is possible.
METHODS: For 71 young women, from the HVT recordings two parameters were mathematically estimated, reflecting the phonation onset dynamics: The threshold value A(th), corresponding with the myoelastic tone of the vocal folds and a maximum sound pressure level of speech L(max), characterising the efficiency of voice.
RESULTS: Both values are sensitive for functional voice disorders and enable a differentiation between these pathologies. DISCUSSION: Significant differences of the computed parameters between the pathological groups and normal voices substantiate the presented method as a stable and objective tool for medical diagnosis.