The influence of the position of the laryngeal endoscope laryngeal on videokymography

Videokymography is a new high-speed imaging technique to investigate vocal fold vibration. The system has been considered useful in the analysis of irregular signals, making it possible to observe left-right asymmetries, open quotient, propagation of mucosal waves, and movement of the upper and lower margins. The aim of the present study was to verify the correspondence of the videokymographic images with larynx exposition angle variation. Three Brazilian adult female subjects, with no vocal complains, were evaluated. Videokymographic images were obtained with the laryngeal endoscope 90o positioned on the measuring line, perpendicular to the glottal axis - zero degree, during a sustained “ae” vowel, using habitual frequency and intensity. The procedure was repeated twice and adjusted by rotating the camera in fifteen degrees from the perpendicular line to the right and to the left. The results showed clear differences depending on the position of the endoscope, suggesting the standardization of laryngeal exposition to interpretate videokymographic images correctly.