The case study below describes a man with MS who lost the ability to walk, but with the clever use of implanted nerve stimulators they were able to restore his ability to walk. Use of nerve stimulation is only possible because MS is a disease of the central nervous system and leaves the so called peripheral nerves, or peripheral wiring, intact. This is why FES (functional electric nerve stimulation) works. The technique use here is invasive and expensive; it requires the implantation of electrodes and expensive hardware. I personally think this is not the solution to walking-related MS disability. In an ideal world we would want to prevent walking impairment from happening in the first place; we are trying to do that with our treat early and effectively (treat-2-target of NEDA with zero tolerance) paradigm. If this does work then we need a more pragmatic approach. I suspect this will end-up being the commercialisation of exoskeletons that have already been shown to work. At the moment they are too expensive for broad use, but as with all technologies the price will plummet with time. At the moment they are not available for pwMS under the NHS.
Selkirk et al. Feasibility of Restoring Walking in Multiple Sclerosis with Multichannel Implanted Electrical Stimulation. Am J Phys Med Rehabil. 2017 Feb 1. doi: 10.1097/PHM.0000000000000692.
A patient with multiple sclerosis-related gait dysfunction was followed over the course of his disease. Despite aggressive treatment, he developed significant weakness in ankle dorsiflexors and hip and knee flexors and was no longer capable of consistently taking a step on his own. With electrical stimulation of hip and knee flexors and ankle dorsiflexors using implanted electrodes, he was able to consistently walk short distances as far as 30 m, thus significantly improving his Expanded Disability Status Scale score. This case study supports further exploration into the potential benefits of an implanted pulse generator to ameliorate gait dysfunction and improve quality of life for people with multiple sclerosis.