DevRobust Treatment for Mal de Débarquement Syndrome

"The stimulus will be a combination of horizontal visual motion and a head maneuver. The subject will sit in a stationary chair, and a treatment provider will stand behind the subject. While the subject views the slow horizontal motion up to 10°/s of vertical stripes, the provider will gently hold the head of the subject above the ears and tilt the head in the roll (side-to-side) or pitch (up-down) plane by approximately ±20° at the frequency of 0.2 to 0.05 Hz for up to 10 min. The treatment will be repeated with breaks of approximately 5 min. A treatment session will last no longer 120 min including the breaks.~In Groups 1, 3, and 4, subjects will sit in a chair placed in the center of a cylindrical enclosure of a 95 cm radius, and full-field visual motion will be generated with light projected on the wall of this chamber. In Group 2, visual motion will be presented on the screen of a VR headset. Unlike groups 3 and 4, groups 1 and 2 do not receive any complementary treatment."

The subject will sit in a chair placed in the center of a cylindrical enclosure of a 95 cm radius. Physical motion will be generated by rotating the chair sinusoidally to the left and right, and full-field visual motion will be generated with light projected on the wall of this chamber. Velocity storage will be weakened by inducing a conflict between physical and visual motions. Subjects will be first treated with a stimulus with a peak speed of 5°/s. The stimulus speed will be gradually increased from 5°/s on Day 1 to 40°/s on Day 5. In total, the subjects are expected to undergo 200-280 min of treatment over the five days, broken up into several 10-20 min sessions per day with a 10-min break in between. If signs or symptoms of motion sickness are reported by the subject (nausea, sweating), the session will be immediately paused. Treatment may be continued after a short rest if the discomfort is alleviated or on the following day.

The subject will be situated in darkness and view the movement of a visual pattern presented on a disk, sized 1 m in diameter and placed 1 m away from the subject with its center at the eye level. The disk will be rotated clockwise and counter-clockwise for up to 10 min at a fixed maximal speed within a treatment session but varying across sessions between 5 to 60°/s. Within a single session, the visual stimulus will be first presented with the subject sitting upright in a chair, and then the treatment will be repeated with the subject standing. The disk will be mounted on a vertical sled, so the center of rotation can be kept at the eye level when sitting and standing. A treatment session will be repeated or conducted with an increased visual motion speed up to 60°/s according to the subject's readiness. In total, the subjects are expected to undergo up to 300 min of treatment over the five days, broken up into several sessions per day with a 10-min break in between

"The investigators characterize gravitational pull as a misaligned sense of upright in the velocity storage mechanism, and hypothesize that that this misalignment can be corrected with an opposing visual motion stimulus, e.g., backward pulling will be corrected with upward visual motion.~Patients in Group 5 will undergo view visual motion in a physical setting, and those in Group 6 under a VR setting. In total, the subjects are expected to undergo up to 300 min of treatment over the five days, broken up into several sessions of 1-10 min per day with an approximately 5-min break in between."