Combining differentiated electroglottograph and differentiated audio signals to reliably measure vocal fold closed quotient

Abstract

Over the past few decades researchers have explored the use of the electroglottograph (EGG) as a non-invasive method for representing vocal fold contact during vowel production and to measure the closed quotient (CQ) and open quotient (OQ) of the glottal cycle. The first derivative of the EGG signal (dEGG) can be used to indicate these moments (Childers & Krishnamurthy, 1985). However, there can be double positive peaks in the dEGG as well as a variety of negative peak patterns (Herbst et al., 2010). Obviously these variations will alter any measurements made from the signal. Recently, the use of the dEGG with dAudio signal was reported as a means for more reliable measurement of the CQ from the EGG signal in combination with a time synchronized audio signal. The purpose of this study is to demonstrate the reliability of the dEGG and dAudio for determining CQ across a variety of vocal conditions. Files recorded from group of 15 trained females singing an octave that included their primo passaggio provided the data. Preliminary results indicate high reliability of the CQ measurements in both the chest and middle registers of all of the singers.