Direct measurement of onset and offset phonation threshold pressure in normal subjects.
Phonation threshold pressures were directly measured in five normal subjects in a variety of voicing conditions. The effects of fundamental frequency, intensity, closure speed of the vocal folds, and laryngeal airway resistance on phonation threshold pressures were determined. Subglottic air pressures were measured using percutaneous puncture of the cricothyroid membrane. Both onset and offset of phonation were studied to see if a hysteresis effect produced lower offset pressures than onset pressures. Univariate analysis showed that phonation threshold pressure was influenced most strongly by fundamental frequency and intensity. Multiple linear regression showed that these two variables, as well as laryngeal airway resistance, most strongly predicted phonation threshold pressure. Two of the five subjects demonstrated a significant hysteresis effect, but one subject actually had higher offset pressures than onset pressures.
Plant
Randall L
RL
Department of Otolaryngology/Head and Neck Surgery, Eastern Virginia Medical School, Norfolk, Virginia 23507, USA. rlplant@anmc.org
Freed
Gary L
GL
Plant
Richard E
RE
D000328:Adult; D000399:Air Pressure; D000403:Airway Resistance / Q000502:physiology*; D005260:Female; D006801:Humans; D007830:Larynx / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010699:Phonation / Q000502:physiology*; D010700:Phonetics; D013018:Sound Spectrography; D013061:Speech Acoustics; D014827:Vocal Cords / Q000502:physiology*