Estimation of Vocal Fold Impact Stress using the Electoglottogram Signal

Peter Murphy, Anne-Maria Laukkanen, Elinita Mäki

The amount of mechanical load exerted on the vocal fold tissue during loud phonation was studied. Glottal resistance (pressure/flow), CQ (closed time/ fundamental period) and the second derivative of the electroglottographic signal (D2EGG) were employed to estimate the mechanical loading of the folds.
In this pilot study a set of five male and five female talkers were analysed (from recordings of thirty healthy subjects -10 males, 20 females- attending a vocal loading test consisting of shouting numbers for five minutes at 90 dB, measured at one-meter distance, in a well-damped studio). Before and after the loading test, repetitions of [pa:] were recorded using habitual loudness and loud phonation. Acoustic and electroglottographic (EGG) recordings and oral pressure and airflow registrations, obtained with the aid of an anesthezia mask, were made from the syllable repetitions. Oral pressure during [p] was used as an estimate of subglottic pressure. In order to obtain an estimate of impact stress during phonation, the EGG signal was analyzed and CQ and D2EGG were estimated. The results from this preliminary data reveal that D2EGG is strongly correlated with CQ, which has previously been shown to correlate with impact stress. This result and its implications are discussed in terms of the underlying production mechanism.

Peter Murphy
Department of Electronic and Computer Engineering
University of Limerick
Limerick
Ireland
Ph. +353 61 213439 Fax.+353 61 338176
Peter.Murphy@ul.ie
Anne-Maria Laukkanen, Elinita Mäki
Department of Speech Communication and Voice Research
(Kalevantie 4),
33014 University of Tampere,
Finland
Tel. +358 (0)3 3551 7249, +353 (0)3551 6191 Fax: +358 (0)3 3551 6063
Anne-Maria.Laukkanen@uta.fi elinita.maki@uta.fi