## 1 Introduction  
Many common voice disorders are believed to be primarily the result of vocal behaviors associated with voice misuse/overuse that result in vocal fold tissue trauma, or phonotrauma. Phonotrauma is typically associated with persistent vocal fold tissue inflammation, chronic cumulative tissue damage, and environmental influences that are the result of undesirable vocal behaviors that lead to the formation of benign vocal fold lesions such as nodules and polyps [1; 2; 3]. Although vocal fold impact stress (in the direction of tissue motion) and shear stress (along the tissue surface) are assumed to be critical factors in causing phonotrauma [2; 4; 5; 6], there is a paucity of empirical data for these forces, including information about the actual levels that cause tissue trauma. This lack of data is largely because the in vivo measurement of vocal fold impact forces and pressures during phonation has proven challenging, and only a few published studies have been able to successfully measure vocal fold collision characteristics via intraglottally positioned devices [7; 8; 9]. [PERSON] et al. [7; 8] developed a piezoresistive pressure sensor with a flat frequency response up to 50 kHz and a linear sensing range of 0-14 kPa (0-140 cm H\({}_{2}\)O). The pressure sensing element was 1.8 mm wide \(\times\) 0.4 mm thick and inserted transorally via a curved cannula. Similarly, [PERSON] et al. [9] developed a transorally positioned sensor housed on the tip of a curved cannula; however, the sensing element was a piezoelectric force sensor with a flat frequency response up to 25 kHz and a linear sensing range for measured forces from a 2.5 mN noise floor up to 200 mN. The force sensing element was 10 mm wide \(\times\) 0.29 mm thick. For both devices, accurate positioning of the sensor in the vertical (superior-inferior) direction was critical and was accomplished using simultaneous laryngeal imaging using a rigid, transoral endoscope held in the contralateral hand of the endoscopist. As acknowledged in these studies, consistent vertical positioning is challenging due to the limitations of the two-dimensional endoscopic view of the larynx. Recordings had to be reviewed for accurate intraglottal sensor positioning, with only a small subset of recordings adequate for further analysis. The current work sought to address the challenge of vertical placement of the vocal fold collision sensing element by incorporating an inline, dual-sensor configuration. It was hypothesized that utilizing a two-sensor probe setup would allow for the simultaneous acquisition of both vocal fold collision pressure and subglottal pressure during phonation. A distal pressure sensor would thus capture the time-varying subglottal pressure signal, while a proximal sensor would measure both the intraglottal pressure signal (aerodynamic energy during the open phase) and vocal fold collision pressure signal (impact stress during the closed phase). Directly measuring the subglottal pressure signal was expected to provide important feedback to experimenters regarding accurate vertical positioning of the intraglottal pressure sensor in real time. This paper reports on the proof of concept of a new in vivo dual-sensor intraglottal/subglottal pressure (ISP) probe that was validated using excised whole-mount and hemilarynx phonatory models. The work follows on recently published pressure sensor characterization and validation using synthetic vocal fold models that directly informed the specifications of the in vivo probe [10]. Results from the synthetic vocal fold experiments pointed to the importance of (1) a flat pressure-sensing surface and (2) confirmation that the pressure sensor is accurately positioned to measure vocal fold contact. To validate the dual-sensor ISP probe on the bench, a hemilarynx configuration was built to enable simultaneous imaging of the superior and medial surfaces of the functional vocal fold [11; 12], while also allowing for superior-inferior advancement of the pressure sensors relative to the phonating vocal fold.