Monika Tigges

A Novel 22q11.2 Microdeletion in DiGeorge Syndrome

We thank the family for their cooperation and patience, and we thank Silke Appel (Berlin) for help with the BAC screening.

Imaging of vocal fold vibration by digital multi-plane kymography.

Digital multi-plane kymography is presented as a new method to demonstrate vocal fold vibration from digital high-speed recordings. Single lines from digital high-speed sequences of laryngoscopical examinations are concatenated to images, which are called kymograms. In order to reveal anterior-posterior (AP) modes of vibration several kymograms from different location of the glottis can be obtained from a single recording. Problems due to rotation of the endoscope or relative movements of patient or examiner can be solved by image processing algorithms specifically designed for this application. Different types of phonation onset and examples of voice disorders are given.

Phonation onset: Vocal fold modeling and high-speed glottography

Phonation onset is discussed in the framework of dynamical systems as a Hopf bifurcation, i.e., as a transition from damped to sustained vocal fold oscillations due to changes of parameters defining the underlying laryngeal configuration (e.g., adduction, subglottal pressure, muscular activity). An analytic envelope curve of the oscillation onset is deduced by analyzing the Hopf bifurcation in mathematical models of the vocal folds. It is governed by a single time constant which can be identified with the physiological parameter phonation onset time. This parameter reflects the laryngeal state prior to phonation and can be used as a quantitative classification criterion in order to assess the phonation onset in clinical diagnosis. The extraction of the phonation onset time from simulated time series using a simplified two-mass model and from digital high-speed videos is described in detail. It shows a good agreement between theory and measurement.

Quantitative characterization of functional voice disorders using motion analysis of high-speed video and modeling

A semi-automatic motion analysis software is used to extract elongation-time diagrams (trajectories) of vocal fold vibrations from digital high-speed video sequences. By combining digital image processing with biomechanical modeling we extract characteristic parameters such as phonation onset time and pitch. A modified two-mass model of the vocal folds is employed in order to fit the main features of the simulated time series to those of the extracted trajectories. Due to the variation of the model parameters, general conclusions can be made about laryngeal dysfunctions such as functional dysphonia. We show the first results of semi-automatic motion analysis in combination with model simulations as a step towards a computer aided diagnosis of voice disorders.

High-speed imaging and image processing in voice disorders

A digital high-speed camera system for the endoscopic examination of the larynx delivers recording speeds of up to 10,000 frames/s. Recordings of up to 1 s duration can be stored and used for further evaluation. Maximum resolution is 128 multiplied by 128 pixel. The acoustic and electroglottographic signals are recorded simultaneously. An image processing program especially developed for this purpose renders time-way-waveforms (high-speed glottograms) of several locations on the vocal cords. From the graphs all of the known objective parameters of the voice can be derived. Results of examinations in normal subjects and patients are presented.

Bewegungsanalyse der Pharyngo-Ösophagealen Schleimhaut

In dieser Arbeit werden aktiven Konturen verwendet, um die wellenformigen Bewegungen des pharyngo-osophagealen Segmentes wahrend der Phonation mit einer Stimmventilprothese zu beschreiben. Zur Parametrisierung der Schwingungen werden die Kurvenparameter Umfang, Flache sowie Zirkularitat als Funktionen der Zeit berechnet. Aus diesen Parametern last sich zudem die Grundfrequenz fo der pharyngo-osophagealen Schleimhautbewegung ermitteln.

Automatische Verfolgung von Augenlidbewegungen und Korrelation mit EMG-Daten

Es wird eine Methode vorgestellt, mit der es moglich ist, ohne spezielle Marker oder Markierungen die Bewegungen von Augenlidern zu detektieren. Dieses Verfahren basiert auf der Methode des Template-Matchings mittels Korrelation, die um eine dynamisches Template-Adaption sowie um Subpixel-Genauigkeit erweitert wurde. Das Verfahren wird anhand von Beispielen an Probanden und Patienten demonstriert. Die Aufnahmen wurden mit einer digitalen Hochgeschwindigkeitskamera gemacht, die Bewegungen der Augenlider wurden mittels unterschiedlicher Stimulationen hervorgerufen.

Computerbasierte Bewegungsanalyse von Stimmlippenschwingungen

Ein System zur automatischen Bewegungsanalyse von Stimmlippenschwingungen wird vor dem Hintergrund der fur die Bewegungsganalyse bekannten Korrespondenz-, Verdeckungs-, und Aperturprobleme vorgestellt und diskutiert. Um die genannten Probleme auszugleichen, ist der beschriebene Ansatz wissensbasiert und flachenorientiert.