Visualization and quantitative Analysis of Vocal Fold Vibrations using Phonovibrograms

Jörg Lohscheller, Hikmet Toy, Ulrich Eysholdt and Michael Döllinger

The clinical examination of voice disorders demands an endoscopical observation of vocal fold vibrations. Digital high-speed endoscopy is the state-of-the-art technology for investigation normal and pathological vocal fold vibrations. We present a visualization strategy which transforms the segmented contours of vocal fold edges into a set of two dimensional images, denoted Phonovibrograms (PVG). Within the PVGs the individual type of vocal fold vibration becomes uniquely characterized by specific geometric patterns which can be seen as fingerprints of vocal fold vibration. The PVGs give an intuitive access on the type and degree of the laryngeal asymmetry which is essential to quantify the effects of functional and organic voice disorders.
To determine the vibration characteristics, we present an image processing approach that automatically analyzes the relevant structures within a PVG. Thus, for each vocal fold the vibration type — comprising the opening and closing phase — can be quantified and classified. The results of the PVG classification will be presented in 12 high-speed sequences recorded from 6 normal and 6 pathological voices. It will be shown, that a classification of the vibration type can be performed very precisely even in disturbed vocal fold vibrations. The obtained PVG images can easily be documented and stored on a hard-disc-drive using a lossless image data-format. Using PVGs conventional and surgical voice therapy can be quantitatively assessed and documented which is indispensable for evidenced based medicine. The quantitative description of the geometric pattern within the PVGs has the potential to realize a novel classification of vocal fold vibrations.

Jörg Lohscheller, Hikmet Toy, Ulrich Eysholdt and Michael Döllinger
Corresponding author: Dr. Jörg Lohscheller
Email: joerg.lohscheller@phoni.imed.uni-erlangen.de
UniversityHospital Erlangen, Medical School
Department of Phoniatrics and Pediatric Audiology
Bohlenplatz 21, 91054 Erlangen, Germany
Tel. : (+49)-9131-85-33 815 Fax. : (+49)-9131-85-39 272

Co-Author 1: Dr. Hikmet Toy
Email: hikmet.toy@phoni.imed.uni-erlangen.de
UniversityHospital Erlangen, Medical School
Department of Phoniatrics and Pediatric Audiology
Bohlenplatz 21, 91054 Erlangen, Germany
Co-Author 2: Prof. Dr. Dr. Ulrich Eysholdt
Email: eysholdt@phoni.imed.uni-erlangen.de
University Hospital Erlangen, Medical School
Department of Phoniatrics and Pediatric Audiology
Bohlenplatz 21, 91054 Erlangen, Germany
Co-Author 3: Dr. Michael Döllinger
Email: michael.doellinger@phoni.imed.uni-erlangen.de
University Hospital Erlangen, Medical School
Department of Phoniatrics and Pediatric Audiology
Bohlenplatz 21, 91054 Erlangen, Germany