| dc.description.abstract | Intraoral functions are results of complex sensorimotor loop operations, and therefore vulnerable to the small functional or neural defects. To secure the vital intraoral functions, it is important to find a way to favorably intervene the intraoral sensorimotor loop operations. The tongue and the soft palate are heavily associated with several sensorimotor loops for intraoral functions, with their dense neural innervations and occupancy of intraoral space. Electrical neuromodulation onto the tongue and the soft palate have a great potential to solve the problems in intraoral functions, such as swallowing, breathing, and talking. However, both the tongue and the soft palate have not been characterized well yet for electrical neuromodulation. In this study, we characterized electrical impedance between electrodes across the tongue and the soft palate, measured stimulation thresholds for perception, and identified type of perception evoked by the stimulation. For impedance characterization, we selected R-R-C model, which is typically used for skin impedance characterization. We found the equivalent series resistance, parallel resistance, and parallel capacitance values for R-R-C model, as 1.837 kΩ, 5.741 kΩ, and 30.148 nF, respectively. We also found that the perception thresholds for the tongue tip, lateral-inferior side of the tongue, and the soft palate as 0.16, 0.34, and 1.47 mA, respectively. As the amplitude of stimulation increases, subjects felt more natural pressure-like sensation than electrical tingling, in all three locations. Subjects could not distinguish the temporal difference of perception between 25 and 100 Hz well. The discomfort at the highest amplitude of stimulation was described as stabbing on the soft palate and stiffness on the tongue. Based on the electrical characterization of the tongue and the soft palate, we found out the effect of electrical neuromodulation, onto the tongue and the soft palate, on the pharyngeal phase of swallowing and obstructive sleep apnea, which is one of the most important intraoral sensorimotor loop operations. | en |
