Glottal area waveform analysis of benign vocal fold lesions before and after surgery.

Glottal area waveform (GAW) is the plot of relative glottal area versus time through 1 representative glottal cycle. It is derived from the quantitative analysis of the videostroboscopic image. A GAW analysis was performed on 24 patients before and after microlaryngeal phonosurgery. Patients with vocal fold polyps, polypoid degeneration, cysts, sulcus vocalis, and Reinke's edema were included. From each GAW, 5 parameters were determined and compared: maximum normalized glottal area, maximum opening rate, maximum closing rate, percent open time at 50% glottal opening, and glottal gap size. Statistically significant differences in postoperative states included an increased maximum glottal area, an increased maximum opening rate, and an increased maximum closing rate. Glottal opening and closing rate are objective measures of vocal fold pliability that have clinical relevance. The GAW may be used to quantitate vocal fold vibratory capability.