Assisting walking balance using a bio-inspired exoskeleton controller.
M Afschrift, E van Asseldonk, M van Mierlo and 5 others
PMID 37370175WHAT IT FOUND
A bio-inspired ankle exoskeleton controller that used body sway feedback reduced muscle effort and limited balance loss after treadmill pushes and pulls.
It was tested only in 12 healthy walkers, not patients.
Key findings
01The controller that used whole-body center of mass velocity feedback tracked ankle moments more closely during perturbed walking, with error 9 Nm versus 14 Nm without it.
02With center of mass velocity feedback, the exoskeleton delivered higher ankle moments after pushes and lower ankle moments after pulls than during unperturbed walking.
03After push perturbations, the center of mass feedback controller reduced forward center of mass displacement by 9% and soleus activity by 10% compared with the default controller; after pull perturbations, it reduced backward center of mass displacement by 18% and tibialis anterior activity by 16% compared with the default controller.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Only 12 healthy participants were tested, and none had musculoskeletal or neurological disorders, so it is unknown whether people with balance impairments would benefit. The exoskeleton was heavy, 5 kg per ankle, and was originally designed for individuals with complete spinal cord injuries, so it may not resemble a practical clinical device. Testing was on a treadmill at 0.6 m/s with pelvis push and pull perturbations, not overground walking or everyday balance challenges. Participants wore a safety harness, so the results do not show what would happen if a fall were possible. The authors compared with minimal impedance rather than walking without an exoskeleton, so absolute benefit over no device is not shown. Reduced muscle activity does not prove reduced metabolic energy consumption. A fourth controller was tested but not included in the reported study.
Declared interests
No conflict-of-interest or funding statement is included in the supplied article text. The supplied publication metadata lists non-U.S. government research support.
The easy way to misread this
Do not conclude that this exoskeleton controller is ready to improve balance or reduce falls in patients. It was tested only in 12 healthy people on a treadmill with a heavy research exoskeleton, and the authors describe the result as proof of principle.