We evaluated the effectiveness of vibrotactile feedback to enhance protective stepping with a view to developing a prosthesis
for patients with balance disorders. Subjects standing on a moving walkway were exposed to an unpredictable, abrupt backwards
translation of the support surface that required a step response to remain standing. The subjects were 15 normal young, 15
normal elderly and 9 patients with either bilateral vestibular loss or peripheral neuropathy. The initial passive displacement
of the body was recorded by a gyroscope placed on the leg which triggered a vibration pulse to the trigeminal distribution
on the forehead to cue a forwards step. Stepping responses and postural sway, with and without vibration feedback, were compared.
Vibration produced significantly shorter stepping reaction times only in the elderly normals with naturally slower stepping.
Patients did not benefit in any way. We conclude that the effectiveness of vibration biofeedback appears limited. Any enhancement
of compensatory stepping might be triggered by speeding the decision to step rather than by creating a specific stimulus-response
loop.
Key words biofeedback - forward stepping - aged - vestibular diseases - peripheral neuropathy