In the Department of Phoniatrics and Pediatric Audiology at the University Hospital Erlangen a medical imaging was developed for the vibration analysis of vocal folds: the Phonovibrogram (PVG). Within the framework of research on this process PVG-features will be developed and analysed, which should enable an objective differentiation between healthy and organically or functionally pathological vocal fold vibrations. The features wouldn't be extracted from the whole PVG-scope, but from single images, each of which contains the information of precisely one opening and one closing phase of a vocal fold. For the detection of these single images, the so-called cycles, a robust approach is designed and implemented. Subsequently a new display format is developed, which concentrates the information of the PVG on the cycle-layer: the S-Cycle (Standard/Spiegl-Cycle)

PVG-Examples

In the following some (healthy and pathological) vocal folds and their according PVGs are pictured.

a) Healthy vocal folds

b) Vocal folds with nodules

c) Vocal folds with polyp on the right (!) side

d) Vocal folds with paresis on the left (!) side

PVG to S-Cycle Conversion

In an upcoming step the PVG will be divided in subparts: the cycles. The mean and variance picture of all these cycles give the S-Cycle (Standard/Spiegl-Cycle). The following figure shows the S-Cycle of an healthy PVG.

Classification of Vocal Fold Vibrations

Different vocal folds from different people vibrate differently. Due to this fact every person has it's own PVG/S-Cycles, like a fingerprint. With a vocal fold disorder this fingerprint changes. Idea: Analyze the PVG/S-Cycle to find any hint, that allows an automatic classification of the underlying disorder. The disorders to distinguish are: organic (Nodules, Polyp, Paresis) and functional (motion irregularities).