Correlation between glottal area and photoglottographic signal in normal subjects

Photoglottography (PGG) is an established technique for depicting the vibra tory patterns of the vocal folds. The present study investigates the correl ation between the glottal area and the corresponding PGG signal. Six normal (five male, one female) subjects who did not use their voices professional ly were investigated during constantly sustained phonation at spontaneous p itches. Laryngostroboscopy was performed in combination with PGG. The simul taneously recorded laryngostroboscopic images and PGG signals were directly digitized and stored on a computer. The correlation between the glottal ar ea and the corresponding PGG amplitudes across each vibratory cycle of the vocal folds was calculated and they were found to be highly and positively correlated (r = 0.973, p < 0.001). The PGG signal reflects changes in the g lottal area during the vibration cycle of the vocal folds. The proposed sim ultaneous laryngostroboscopic and PGG technique has proved to be useful for facilitating the interpretation of changes in glottal area.