Physical task stress affects the acoustic speech wave in various ways. Motivated by observations that fundamental frequency and open quotient are affected by physical task stress, this study examines the effects of physical task stress on parameters of the estimated glottal volume velocity waveform. It is shown that, in contrast to other types of phonation such as soft, loud, breathy, or pressed voice, physical task stress has little effect on the glottal waveform parameters chosen for analysis. Further, the use of glottal waveform parameters in a stress detection system does not improve the system accuracy, again in contrast to other types of non-neutral speech. These results suggest that a medium level of physical task stress does not greatly perturb vocal fold behavior, and the search for explanations for the spectral perturbations that make stress detection possible must turn to other directions.

Index Terms: glottal waveform, physical task stress, stress detection