Grutio: System for Reproducing Swallowing Sensation Using Neck-Skin Movement

Many activities can be carried out in virtual reality environments, and at present, reproducing the activity of eating or drinking is one developing field. Virtual eating or drinking can be divided into two types: those with food in the mouth and those without placing food in the mouth. Many studies have focused on changing the taste, size, and texture of food when eating or drinking, but few studies have focused on recreating the sensation of eating or drinking without actually placing food in the mouth. One of the challenges in virtually reproducing eating or drinking without the use of food or drink is how the sensation of swallowing is recreated in the esophagus. Herein we show Grutio, a device for recreating the sensation of swallowing by causing skin deformations that are the same as those during actual swallowing. When participants were asked to compare the sensation of drinking water with the recreated sensation, 66% of the participants had a stable pattern of swallowing sensations over the three-day experiment. participants who did not have a stable pattern also felt swallowing at least three times, and all participants were able to feel swallowing. The hardness and viscosity of the virtual swallowed food could be changed by adjusting the rate of skin deformation. The system allowed most users to virtually feel the sensation of swallowing through calibration. Although there were individual differences, the results of this study suggest that applying skin deformations externally to the neck can reproduce swallowing sensations internally.