Respiratory and laryngeal responses to an oral air pressure bleed during speech.

Researchers have hypothesized that the respiratory and laryngeal speech subsystems would respond to an air pressure bleed, but these responses have not been empirically studied. The present study examined the nature of the responses of the respiratory and laryngeal subsystems to an air pressure bleed in order to provide information relevant to the nature of motor control for speech. Participants produced a syllable train consisting of 7 syllables of [pa] 10 times with and without an air pressure bleed in place. Acoustic, aerodynamic, and respiratory kinematic data were collected. In the bleed condition, peak intraoral air pressure and average oral airflow during the [a] were lower, lung and rib cage volume excursions were longer, and rib cage volume terminations were more negative. This study provides empirical data demonstrating a clear interaction among the speech subsystems. Both active and passive mechanisms are suggested by the subsystems' responses.