This sounds like a TENS unit, which is a small device fairly commonly used to treat muscle and nerve pain. I have neck and back issues and use them as needed. It can cause the nearby muscles to twitch if turned up too high and it can cause skin irritation if used for a long time. Most doctors will inform the patient not to use the electrodes on the head, directly over the spine, or directly over the heart. If you do end up putting it on your spine, you’re in for quite the adventure because it can cause stimulation throughout the entire nerve. For example, if I put it right over a major nerve for moving the arm, my entire arm twitches. If I had a kid, I’d certainly want more of an explanation than this: “The system delivers the low-level electrical stimulation to the branches of the trigeminal nerve, which sends therapeutic signals to the parts of the brain thought to be involved in ADHD. While the exact mechanism of eTNS is not yet known, neuroimaging studies have shown that eTNS increases activity in the brain regions that are known to be important in regulating attention, emotion and behavior.” This reeks of the whole “throwing shit at the wall and seeing what sticks” mindset. People who prescribe it should have to use it themselves!