Abstract
Videostroboscopic assessment of the vocal folds is a technique that relies solely on the subjective visual perception of the clinician. The purpose of this study was to determine intra- and inter-rater reliability of perceptual ratings for assessing vocal fold structure and function in laryngeal videostroboscopic analysis. The raters consisted of ten specialists in voice who had more than three years of experience viewing videostroboscopic examinations. Two videostroboscopic segments, which provided the best view of the vocal folds and averaged three minutes, were extracted for four adults, two men and two women, ranging in age from 34 to 58 years. A standard videostroboscopic form was employed. Thirteen stroboscopic parameters for each subject were rated on a multiple point scale. Additionally information was sought on perceived vocal quality, diagnosis and management. No case history information was supplied. Intra- and inter-rater reliability was obtained for vocal quality, thirteen stroboscopic parameters, diagnosis and management. In order to obtain intra-rater reliability data all recordings were evaluated twice by two raters. Inter-rater reliability in this study was extremely poor with combined measures of agreement ranging from – 0.092 (45% in amplitude) to 0.46 (60% in phase closure). In contrast to inter-rater agreement, significantly higher levels of intra-rater agreement were obtained. It would seem from these results that it is difficult, based on visual perception alone, to differentiate between normality and dysfunction, with regard to what are considered the key phenomena of the glottic wave.