Effects of prolonged oral reading on F-0, SPL, subglottal pressure and amplitude characteristics of glottal flow waveforms

The effects of prolonged (5 X 45 minute) reading (vocal loading) on fundame ntal frequency (F-0), sound pressure level (SPL), subglottal (intraroral) p ressure (p), and two glottal flow waveform parameters (AC amplitude of glot tal flow, f, and negative peak amplitude of differentiated flow (d) of norm al female and male subjects (N = 80) were studied. Two rest (morning and no on) and three loading (two in the morning and one in the afternoon) samples were recorded and analyzed. The glottal waveforms were obtained by inverse filtering of the acoustic pressure waveforms of speaking voice samples. Th e analyses ses were based on measurement and inverse filtering of the first stressed syllable of "paappa" words repeated 3 X 5 times for normal, as so ft as possible, and as loud as possible phonation. In normal phonation the parameter values changed statistically significantly due to loading. In man y cases the values obtained in the morning samples changed after the first loading session. This is interpreted as a vocal "warming-up effect." Especi ally in soft phonation p, d, and f were sensitive indicators of vocal loadi ng. In both normal and soft phonation, the SPL, p, d, and f values tended t o rise due to prolonged reading in the morning and afternoon samples, indic ating increased effort (normal phonation) and a rise in the phonatory thres hold (soft phonation). The lunch break vocal rest ("rest effect") considera bly affected the parameter values in many cases.