Tseng WH, et al. - Using the airflow interruption method, researchers explored the connection between F₀ and P_s in awake patients noninvasively. The final analyses included 32 healthy volunteers (aged 20-47 years). When the candidates sustained voicing the vowel /o/ at 3 incremental frequencies 4 semitones apart in the modal register (F1, F2, F3), the relationships between F₀ and P_s, described as the slope (Hz/kPa), were examined. According to findings, the higher the vocal fold tension, the smaller the slope between F₀ and P_s has been shown. It is theoretically useful for clinical application to use the relationship between F₀ and P_s as an analog of vocal fold stiffness.