Glottal airflow and electroglottographic measures of vocal function at multiple intensities

Ten normal female subjects produced syllables at 5 dB increments from soft to loud. The differentiated electroglottogram (dEGG) open and speed quotients were compared to similar quotients from the inverse-filtered airflow waveform. The latter were measured according to objective and subjective criteria. The data indicate that the open quotient from the airflow waveform decreased as the intensity increased. The dEGG open quotient did not demonstrate this trend. The speed quotient from airflow increased initially with vocal intensity and decreased again as the intensity ceiling was approached. The ratio of closing to opening slopes calculated from peaks in the dEGG signal followed a similar pattern. While the trends across intensity conditions were found to correspond for several of the measures, the absolute values obtained using the different methodologies were not comparable.