Preliminary evaluation of stroboscopy system using multiple light sources for observation of pathological vocal fold oscillatory pattern.
OBJECTIVE
Laryngostroboscopy is used to check the oscillatory patterns of the vocal folds. However, the use of one single flash timing cannot give a clear view of abnormal vocal fold oscillations that have multiple fundamental frequencies. Visualization of such complex vocal fold movements will be helpful in the diagnosis of diplophonia, a pathological condition in which the vocal folds produce multiple tones at the same time.


METHODS
We developed a new stroboscopy-based technique using multiple light-emitting diodes (LEDs) and image analysis. Specific flash timings for each LED, suitable for accurate visualization, were determined on a computer according to an algorithm based on frequency analysis. The image analysis extracted the necessary parts of the captured images to yield a clear slow-motion view of the oscillations. The series of visualization procedures took advantage of the narrow-spectrum light property of LEDs, thereby yielding a degradation-free picture.


RESULTS
Feasibility tests using a mechanical vocal fold model demonstrated that this computer-assisted system allows observation of the pathological oscillatory patterns as one single video. They would not be clearly visualized by conventional stroboscopy.


CONCLUSIONS
Because of its relatively simple use and inexpensive construction, the proposed technique can become one potential option for clinical assessment of pathological vocal fold oscillations.
Deguchi
Shinji
S
Division of Industrial Innovation Sciences, Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan.
Ishimaru
Yuuki
Y
Washio
Seiichi
S
D004867:Equipment Design; D005240:Feasibility Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008962:Models, Theoretical; D015203:Reproducibility of Results; D049489:Stroboscopy / Q000295:instrumentation*; D014827:Vocal Cords / Q000503:physiopathology*; D014832:Voice Disorders / Q000175:diagnosis* / Q000503:physiopathology