title: Four-pole galvanic vestibular stimulation causes body sway about three axes.
abstract: Galvanic vestibular stimulation (GVS) can be applied to induce the feeling of directional virtual head motion by stimulating the vestibular organs electrically. Conventional studies used a two-pole GVS, in which electrodes are placed behind each ear, or a three-pole GVS, in which an additional electrode is placed on the forehead. These stimulation methods can be used to induce virtual head roll and pitch motions when a subject is looking upright. Here, we proved our hypothesis that there are current paths between the forehead and mastoids in the head and show that our invented GVS system using four electrodes succeeded in inducing directional virtual head motion around three perpendicular axes containing yaw rotation by applying different current patterns. Our novel method produced subjective virtual head yaw motions and evoked yaw rotational body sway in participants. These results support the existence of three isolated current paths located between the mastoids, and between the left and right mastoids and the forehead. Our findings show that by using these current paths, the generation of an additional virtual head yaw motion is possible.
authors.affiliation: 1] Graduate School of Information Science and Technology, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan [2] Japan Society for the Promotion of Science Research Fellowship for Young Scientists (DC1), 5-3-1 Kohjimachi, Chiyoda-ku, Tokyo, Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Aoyama
authors.affiliation: Graduate School of Information Science and Technology, Hokkaido University, Nishi 9-Chome, Kita 14-Jo, Kita-ku, Sapporo, Hokkaido, 060-0814, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Iizuka
authors.affiliation: 1] Graduate School of Information Science and Technology, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan [2] Center for Information and Neural Networks (CiNet), National Institute of Information and Communication Technology, 1-4 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Ando
authors.affiliation: 1] Graduate School of Information Science and Technology, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan [2] Center for Information and Neural Networks (CiNet), National Institute of Information and Communication Technology, 1-4 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Maeda