Acoustic and physiologic characteristics of inspiratory phonation.

Voice produced on inhaled air is a form of phonation that has received relatively little attention despite its apparent usefulness in the assessment of vocal function. This preliminary investigation was designed to describe the general characteristics of vocalization driven by an ingressive phonatory airflow. Vocal fundamental frequency (F0), electroglottographic (EGG), and airflow measures were examined in 16 normal men and women, who alternated between inspiratory and expiratory voice. Mean F0 routinely increased during inspiratory voice segments, shifting on average 5.1 semitones above the subjects' comfortable expiratory voice frequency. EGG data showed inspiratory voice to be associated with a more symmetrical pattern of vocal fold contact characterized by a prolonged interval of increasing contact. Both short-term F0 variability (jitter) and EGG amplitude perturbation were significantly higher during inspiratory voice. Stroboscopic examination of four of the subjects showed caudal displacement of the larynx and lengthened vocal folds associated with inspiratory phonation. The absolute airflow rate was significantly greater for inspiratory phonation, on average 48.5% higher than during normal expiratory voice. It was also found that both inspiratory pulse and falsetto vibratory patterns could be produced by at least some of the subjects, indicating some control over the mode and frequency of vocal fold vibration when driven by an ingressive airflow.