I sympathize with your situation and understand your frustration. Medical requirements should trump most policies the way pedestrians have the right of way over vehicular traffic.

However, ANA, like any business, has the right to refuse service to anyone, at any time, for any reason. They are not saying you can't fly, just not with that device. I'm sure you can find other options, perhaps less effective, but sleeping on a flight is not mandatory. I realize it's a long flight, but nobody's forcing you to do it.

Whether or not the manufacturer of the device rates it as safe is irrelevant. Clearly, ANA has not had a chance to test it, and they are not about to risk your health, the operational functionality of the electrical system on board, to say nothing of the safety of the other passengers due to any one passenger's needs.

ANA has an obligation to turn the flight around should somebody get sick. ANA has an obligation to make an emergency landing should somebody die. ANA has no obligation to accommodate special needs. You think they do, but they don't. No airline does. In that case, federal and international law trump all.

The best solution: take your business elsewhere.