Class I Dynamic Laryngoscope (Laryngeal Stroboscope) System

Videokymgraphy (VKG) System, Model 8900

KayPENTAX is pleased to offer the newest generation Videokymography (VKG) System as part of our comprehensive line of laryngeal imaging tools.

VKG is a powerful technique for high-speed line scanning (7200 lines/second) of the vocal folds to produce a composite black-and-white image representing successive glottal cycles. The resulting image, known as a kymogram, is a unique display of multiple glottal cycles at a glance. This allows viewing and documenting such features as aperiodic vibration, left-right asymmetry, presence of mucosal wave, and duration of glottal closure within a single image. In addition, VKG reveals features that are not apparent in full-frame video, such as cycle-to-cycle variability, frequency and phase differences between the left and right vocal folds, vertical phase differences between the upper and lower vocal fold margins, opening vs. closing duration, and cycle aberrations (defined as features that disturb the shape of the vibratory cycle while not necessarily disturbing the periodicity of the vibration—for example, due to a lesion). Given these unique capabilities, VKG is an ideal complement to stroboscopy. A drawing of an idealized VKG image, showing two glottal cycles with key features labeled.

Improved Image Output
Major improvements in the new generation system include a full-frame color image displayed side by ide with the black-and-white kymogram, greatly facilitating the positioning of the scan line, and higher sensitivity of the CCD image sensors, providing better image quality (with a 300W Xenon ight Source). The scan line is continuously isplayed in white in the full-frame color image.

Innovative New Features
An optical beamsplitter simultaneously provides the image from the rigid endoscope to the full-frame CD and line-scanning CCD, and the position of he scan line is fixed to correspond to the midline of he full image. The camera head houses only the CDs and the beamsplitter, reducing the size and weight for easy handling. A camera controller contains the microprocessor for real-time video image processing and a frame buffer memory that buffers the line images during the frame-blanking period, producing a continuous kymographic display. A front-panel button enables display of the full-frame color image of the vocal folds (without the kymogram), allowing the system to be used for general purpose endoscopy. The camera controller has both analog and digital video outputs; this allows the system to be used without a host computer by connecting the analog output directly to a standard analog monitor, or the system can be hosted by the KayPENTAX Digital Strobe System computer. The latter option allows VKG exams to be recorded, saved, and archived using all the features and functionality of the Digital Strobe software.

Advantages of VKG over Other Types of Imaging
In the world of high-speed imaging, speed and data volume are competing issues; higher speeds are desirable for capturing complex phenomena to be analyzed, but the sheer volume of the resulting data makes analysis an overwhelming task. VKG
represents an ideal compromise in that the scan rate of 7200 lines/second is high enough to capture even the most complex events, while producing results in a low-volume, compact format that is immediately interpretable and does not require further processing to evaluate. This advantage, coupled with the ability to recognize some features that are not easily discernible in other types of imaging, gives VKG a unique role in the study of laryngeal dynamics and the clinical evaluation of voice disorders.

Complementary Laryngeal Imaging Tools
The VKG System complements KayPENTAX’s Digital Strobe System, an indispensible tool for the comprehensive assessment of vocal fold structure and vibratory characteristics, used for routine laryngeal exams in leading hospitals and voice clinics worldwide. The Digital Strobe can serve as a computer host for the VKG system.


  • - Camera Head Dimensions: 34 x 48 x 75 mm
  • - Camera Head Weight: 150 g (5.3 oz)
  • - Controller Dimensions: 325 x 74 x 365 mm
  • - Controller Weight: 4.5 kg (2 lbs)
  • - Lens Mount: Standard C-mount
  • - Formats: NTSC or PA
  • - Full-Frame CCD: ½ Type, 752 x 582 pixels (PAL), 768 x 494 pixels (NTSC)
  • - Scanning Speed: 7200 lines per second