EFFECT OF USING TOPICAL ANESTHETIC DURING HIGH-SPEED DIGITAL IMAGING ON PHONATION ASSESSED BY DIGITAL KYMOGRAPHY PARAMETERS.

High-speed digital imaging (HSDI) is a contemporary method of the phonation process assessment. It records laryngeal images at a rate of up to 8000 frames per second. Digital kymography (DK) extracts high-speed images sampled at a single point along the vocal folds and enables objective quantification of the vocal fold movements. According to the literature, usage of topical anesthetic (TA) in oral cavity, oropharynx and laryngopharynx prior to examination, in order to reduce pain and discomfort level, is optional but the effect of using TA on the phonation process is not well investigated. The aim of this study was to investigate the effect of using TA during HSDI on DK parameters. We performed a prospective double-blind randomized controlled study on 58 healthy subjects. All subjects were examined on 2 consecutive days using TA and using saline solution (placebo) by the same experienced examiner. DK images, made on the middle of the vocal folds, were obtained from HSDI. Vocal folds were examined across glottal cycles and glottal width and period irregularities, left-right phase asymmetry, and the open, closed, opening and closing quotient were calculated. Our data showed that using TA during HSDI did not induce statistically significant changes of DK parameters in healthy subjects.