A Preliminary Study for a Slantwise-Placed Electroglottography

Abstract

Slantwise-placed electroglottography (EGG) was proposed for synchronous use with an ultrasound machine in a previous work. The objective was to confirm the feasibility of this slant EGG, differentiate it from conventional EGG, and give suggestions for its applications. A synchronized system composed of an EGG device, a high-speed video, a sound level meter, and a headset was established. The same phonation conditions were acquired by training subjects to reach the target phonation frequency and intensity. Electrode position was designed, and vocal fold vibration parameters were measured from EGG waveforms recorded in each electrode position. Comparison showed that the characteristic points identified in slant EGG waveforms were consistent with the vibration phase shown by high-speed video images. Phonation frequency measured from slant EGG was highly accurate. EGG amplitude nonlinearly decreased with the increase of electrode distance. Compared with conventional EGG parameters, velocity ratio and glottal closed quotient measured from slant EGG were accurate when electrodes were placed symmetrically and the electrode distance was within a proper length. Slant EGG was proved feasible and can be considered as a useful tool to obtain comprehensive information in investigating the invivo vocal fold dynamics when synchronized with other detecting equipment.