Reactive stepping with functional neuromuscular stimulation in response to forward-directed perturbations.

Only one person with motor complete T4 paraplegia was tested, so the result cannot be generalized to other people with spinal cord injury. The controller was tuned with this one subject in the loop, and thresholds were set empirically, so it may not work the same way in another person. Testing was done in a laboratory with the person holding walker handles and wearing a safety harness, so real-world standing without support was not shown. Only forward perturbations and stepping with the right leg were tested. Step length was 163 mm, around half the length reported for able-bodied adults, and the paper says it is difficult to know whether this step would be sufficient for stabilization. The device did not reduce upper-extremity load or make standing self-stabilizing. The able-bodied comparison values are taken from earlier reports, not measured in this experiment.

The supplied text lists funding from the National Institute of Neurological Disorders and Stroke and the U.S. Department of Veterans Affairs; it does not state an author conflict-of-interest declaration.

Do not conclude that this controller makes standing with an implanted neuroprosthesis safe or self-stabilizing. It was tested in one person in a laboratory with a walker and harness, and the person still had to exert substantial forces on the walker handles to maintain balance.