I actually think that the technology as described would not require FDA approval to be sold, but it might require the same for health insurance claims coverage. It is similar to a tens machine and tens machines have been marketed for a long time and are already approved at the advice of physicians for physical therapy, particularly sorts of tens machine for diabetic neuropathies of the feet and legs. I personally have no idea of the efficaciousness of the tens machines but would love to hear from anyone on the forum who has used them.
You are probably right where Europe is concerned, but anyone wishing to get a device onto the US market would almost certainly file what is known as a '510(k) pre-market notification' with the FDA, which as the authority's own website states "demonstrates that the device to be marketed is at least as safe and effective, that is, substantially equivalent, to a legally marketed device that is not subject to pre - market approval" - in other words, it's not compulsory but worth doing anyway. In the US, at least, that would go a long way towards to qualifying for coverage. I fancy trying out a TENS machine myself, for my back - I often get muscle spasms when getting out of bed in the morning - rather than neuropathy, which, luckily, I haven't suffered too much from recently.