See, this just seems overly investigative. If they were physically fusing the arm to your body, sure, that's a reasonable time for the FDA to investigate. But just because it is related to your body in any way doesn't warrant that sort of careful consideration. Similarily, if the radio was controlling a pacemaker, I wouldn't want it using bluetooth, I'd want something FDA approved. If it's an arm, I probably wouldn't want bluetooth (stupid pairing issues....) but something like the xbee format would be great, not some proprietary and less reliable RF protocol.