The Electrolaryngograph ( Egg ) Is A Non Invasive Device Used For Measure Phonatory Behaviour
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The electrolaryngograph (EGG) is a non-invasive device used to measure phonatory behaviour, specifically vocal fold contact during speech (Abberton, Howard, & Fourcin, 1989; Baken & Orlikoff, 2000; Mooshammer, 2010). The operation of the device involves the placement of two electrodes superficially to the thyroid cartilage at an approximate level to the position of the vocal folds on either side of the subject’s larynx (Baken & Orlikoff, 2000; Winstanley & Wright, 1991). Time varying impedance between the vocal folds is monitored by the voltage exchange from one electrode to the other, which occurs relative to the vocal fold vibrations, and is displayed as an output waveform (Lx = Larynx excitation) as a function of time (Abberton et al., 1989; Baken & Orlikoff, 2000; Mooshammer, 2010; Winstanley & Wright, 1991). Maximal impedance occurs when the vocal folds are abducted, and minimal impedance occurs when the vocal folds are adducted (Baken & Orlikoff, 2000; Mooshammer, 2010).
As many as six different voice qualities have been reported in the literature, however, in this analysis, only modal, creaky, and breathy voice will be discussed (Abberton et al., 1989; Baken & Orlikoff, 2000; Laver, 1980; Mooshammer; 2010). Modal voice is characterised as the quality that includes the range of fundamental frequencies normally used for speaking and singing; its laryngeal characteristic is a neutral mode of phonation, with moderate adductive tension (Laver, 1980). The Lx waveform of