Quantitative color analysis of laryngeal erythema in chronic posterior laryngitis

The purpose of this study was to quantitatively analyze the degree of erythema visible in the larynges of normal subjects and of patients with symptoms of chronic posterior laryngitis. Video-documented examinations of laryngoscopy were digitized and then analyzed using computer image analysis software that allowed quantification of average color values, hue, saturation, and brightness from digitized color images. Documented laryngoscopic images from 7 normal subjects and 64 patients complaining of chronic laryngitis symptoms were examined, and additional patient examinations which were obtained and documented during treatment for reflux laryngitis were analyzed. Analysis was made of five different areas of each laryngeal image: the right and left vocal folds, the right and left vocal processes, and the posterior arytenoid mucosa. Data analysis showed that average color value ratings of redness for the patients with chronic laryngitis were significantly (p <0.0561) greater than the average values for normal subjects for the vocal folds. Color values for redness of the posterior laryngeal structures and vocal folds in the patients who were treated for reflux laryngitis were significantly (p <0.05) reduced over time and correlated with the clinical response to treatment. The data suggest that computer color analysis of documented video-laryngoscopic examinations can provide quantitative data on degree of erythema and may be useful as a quantitative means of diagnosis and documentation of treatment outcome for reflux laryngitis.