Fig. 8.

A: summary of experimental results as % differences in group average performance measures between subjects with vestibular loss and control subjects across tilt velocities in the eyes-closed conditions. B: a schematic of approximate sensory weightings of vestibular and somatosensory inputs for postural orientation across surface tilt velocities based on our results. Our Wg data from groups of control subjects (black solid line) and subjects with vestibular loss (blue solid line) are summarized. The graviceptive somatosensory influence (horizontal dotted lines) and somatosensory-triggered postural responses (vertical dashed lines) follow the ability of our group of subjects with vestibular loss to maintain stability at low and high velocities, respectively. We propose that vestibular responses (red line = control data − vestibular loss Wg data) are most critical at tilt velocities too fast for control by graviceptive somatosensory inputs and too slow for control by somatosensory-triggered postural responses.