Measuring Voice Effects of Vibrato-Free and Ingressive Singing: A Study of Phonation Threshold Pressures.

Summary Background Phonation threshold pressure (PTP), showing the lowest subglottal pressure producing vocal fold vibration, has been found useful for documenting various effects of phonatory conditions. The need for such documentation is relevant also to the teaching of singing, particularly in view of vocal demands raised in some contemporary as well as early music compositions. The aim of the present study was to test the usefulness of PTP measurement for evaluating phonatory effects of vibrato-free and ingressive singing in professional singers. Methods PTP was measured at a middle, a high and a low pitch in two female and two male singers before and after recording voice range profiles (i) in habitual technique, ie, with vibrato, (ii) in vibrato-free, and (iii) in ingressive phonation. Effects on vocal fold status were examined by videolaryngostroboscopy. Results After careful instruction of the singers, no problems were found in applying the PTP method. In some singers videolaryngostroboscopy showed effects after the experiment, eg, in terms of increased mucus and more complete glottal closure. After ingressive phonation PTP increased substantially at high pitch in one singer but changed marginally in the other singers. Conclusion The method seems useful for assessing and interpreting effects of singing in different styles and as a part of voice diagnostics. Therefore, it seems worthwhile to automatize PTP measurement.