Electroglottographic and acoustic changes following type I thyroplasty or autologous fat injection

This study identified the electroglottographic (EGG) and acoustic measures that were most predictive of change in the glottic gap size of patients undergoing type I thyroplasty or autologous fat injection. Simultaneous EGG and acoustic recordings were made before and after autologous fat injection in 23 patients and type I thyroplasty in 45 patients. Relative measures of glottic gap size were obtained before and after operation from videostroboscopic images. Regression and correlation analysis was used to determine the strength of associations between the EGG or acoustic measures and glottic gap changes. A significant regression equation for both patient groups was constructed. The strongest predictors of glottic gap size change were changes in the EGG open quotient, signal-to-noise ratio, and mean fundamental frequency. Glottography provided a clinically useful means of evaluating glottic gap changes in patients undergoing vocal fold medialization procedures. Preoperative-postoperative differences in signal-to-noise ratio and mean fundamental frequency also were correlated to glottic gap size changes, but to a lesser degree.