Abstract

Introduction The semi-occluded vocal tract exercises are widely used in voice therapy and vocal training.Within this category, the resonance tube phonation in water (RTPW) uses a silicon tube with its free end immersed in varying depths of water. Previous studies have reported that the water immersion increases oral pressure (Poral), subglottal pressure (Psub), and open quotient (OQ), also, the bubbling created with exercise, creating a beneficial massaging effect that improves voice quality that can endure after the exercise1 Therefore, RTPW exercises may be useful for pathologies such as unilateral vocal fold paralysis. However, the biomechanical and kinematic effects that this technique has over vibration of the vocal folds are still largely unknown. The purpose of this study is to assess the kinematic effects immediately after RTPW exercises, by means of laryngeal high-speed videoendoscopy in subjects with unilateral vocal fold paralysis. Methods Rigid HSV was recorded at 8000 fps for two female patients with unilateral vocal fold paralysis uttering a sustained vowel /e/ at confortable loudness. Synchronous recordings of microphone, electroglottography, and neck surface acceleration were also obtained. Two different recording sessions were performed for each patient, i.e., pre and post RTPW exercises. A 15 cm silicone tube with 1cm of diameter was immersed into 10 cm of water. The duration of each RTPW exercise was 1 minute with breathing pauses. Digital videokymography (DVK) analysis was performed for every recording, and glottal area, vocal fold displacements and signal spectra were also obtained. Results. Both patients exhibited an increase in the mean displacement and maximum displacement of the vibratory amplitude of the non-paralyzed vocal fold. In the analysis of glottal area and DVK, changes in the entrainments pre and post exercised were observed. For subject 1, preRTPW entrainment was 2:1 and post-RTPW entrainment became 1:1. For subject 2, preRTPW entrainment was 3:1 and post-RTPW entrainment became 3:2, as Both changes in entrainment are considered beneficial, as they significantly enhanced the energy of the fundamental frequency in the resulting spectra.