An Avatar to Measure Vestibular Sensations of Movement

Objective: 1) Report a novel method for measuring vestibular sensations of movement induced by galvanic vestibular stimulation (GVS). 2) Introduce a new approach to quantify vestibular symptoms in patients with vertigo and related disorders. Method: We created a software program using a Logitech wireless joystick to measure and display in three dimensions the manner in which subjects felt movement in response to GVS. Each subject underwent thirty 20-second protocols utilizing ten different combinations of GVS scalp electrode pairs. Results: Three dimensional avatar displays of subject responses to GVS indicated the direction and magnitude of pitch, roll, and yaw as well as the angular velocity of motion. As evident on the avatar display in response to a 2.5 mA GVS pulse, the majority of subjects reported sensation of movement, 19 out of 21 (90%) reporting pitch, 17 out of 21 (81%) reporting yaw, and 17 out of 21 (81%) reporting roll sensations. Conclusion: 1) These data demonstrate a software-based 3 dimensional avatar display system to represent perceived vestibular sensation in response to GVS. 2) This technology may play a role in clinical practice by providing the ability to quantify vestibular symptoms in the assessment of patients with vertigo and related disorders.