Depth-Kymography is the 3D display of the human vocal fold vibrations by measuring its vertical and horizontal movements simultaneously, using a specially designed 3D endoscope. This new 3D imaging method and the new scientific term "Depth-Kymography" are introduced by Dr.Nibu A George, Prof.Frits de Mul and Prof.Harm Schutte et al.   from the University Medical Center Groningen, The Netherlands in 2007. The term "Depth-Kymography" is included in the current medical terminology.
Human vocal folds vibrate in a very complex manner. During phonation vocal folds move in the horizontal and vertical directions. The imaging of the vocal fold vibrations is done by inserting an endoscope through the mouth and the vocal folds are viewed from the top. Hence, with a normal endoscope only the horizontal movements of the vocal folds are visible. Endoscopes used for the visualization of larynx is commonly known as Laryngoscope. With a specially designed 3D laryngooscope, movement of the vocal folds in the horizontal and the vertical directions can be simultaneously measured and displayed with horizontal and vertical displacements forms the two orthogonal planes while time is the third dimension. With this method, researchers were also able to measure the mucosal wave propagation. Depth-kymography has great potential in the investigation of voice disorders and in phonosurgical applications. Depth-Kymography is the next generation of the popular videokymography.
- Depth-Kymography: High-speed calibrated 3D imaging of human vocal folds vibration dynamics, Nibu A George et al., Physics in Medicine and Biology, 53, 2667-2675 (2008).
- Depth-kymography of vocal fold vibrations, part II: Simulations and direct comparisons with 3D-measurements, Frits F.M. de Mul, Nibu A. George, Qingjun Qiu, Gerhard Rakhorst and Harm K. Schutte, Physics in Medicine and Biology, 54, 3955-3977 (2009).
- Videokymography: high-speed line scanning of vocal fold vibration, J. Voice. 10(2),201-205 (1996).