Differential effects of vestibular stimulation on walking and running.

Prompted by our recent observation that an acute vestibular tone imbalance causes less deviation from the intended path when running than when slowly walking, we examined 10 healthy subjects when walking or running at different step frequencies during galvanic vestibular stimulation. Blindfolded subjects were asked to walk (1 Hz step frequency) or run (3 Hz step frequency) straight ahead toward a previously seen target. The mean gait deviation after 10 s was 6.0 +/- 2.4 degrees at 1 Hz and 2.8 +/- 1.8 degrees at 3 Hz step frequency (n = 10; p < 0.001, paired t-test). In a second experiment walking and running in place were investigated. There was no significant difference in body displacement. Walking and running are highly automated processes based on spinal locomotor generators that are under supraspinal control. We conclude that vestibular input is differentially regulated depending on the locomotion speed and pattern used.