Determining the direction of vestibular-evoked balance responses using stochastic vestibular stimulation.

As a tool for investigating vestibulo-motor function, stochastic vestibular stimulation (SVS) has some advantages over galvanic vestibular stimulation. However, there is no technique currently available for extracting direction information from SVS-evoked motor responses. It is essential to be able to measure the direction of response if one wishes to investigate the operation of key spatial transformation processes in the brain. Here we describe and validate a technique for determining the direction of SVS-evoked balance responses based on the correlation between a random waveform of stimulating current and ground-reaction shear force.