VIDEOKYMOGRAPHY - HIGH-SPEED LINE SCANNING OF VOCAL FOLD VIBRATION

A digital technique for high-speed visualization of vibration, called videokymography, was developed and applied to the vocal folds. The sys tem uses a modified video camera able to work in two modes: high-speed (nearly 8,000 images/s) and standard (50 images/s in CCIR norm). In t he high-speed mode, the camera selects one active horizontal line (tra nsverse to the glottis) from the whole laryngeal image. The successive line images are presented in real time on a commercial TV monitor, fi lling each video frame from top to bottom. The system makes it possibl e to observe left-right asymmetries, open quotient, propagation of muc osal waves, movement of the upper and, in the closing phase, the lower margins of the vocal folds, etc. The technique is suitable for furthe r processing and quantification of recorded vibration.