There are still muscles, they slowly deteriorate over time though. When my friend was in 2nd grade or so he could still run and play with the other kids. For a few years after that he could still use a controller to play video games. As he deteriorated further, he couldn't even do that, and got most of his enjoyment from watching other people play games. Heartbreakingly his nephew, who was named after my friend, also suffers from muscular dystrophy since it's a genetic illness.
I'm also sorry because I should have been more succinct. You are correct.
I, too, have a form of muscular dystrophy called Spinal Muscular Atrophy, type II. I deal with a lot of what's being discussed here, i.e. aspiration pneumonia.
That said, there is, at least in my mind, almost no functional difference between not having a muscle and having muscle so deteriorated that it no longer works. Electrical stimuli such as through a TENS unit does nothing.
Back to OPs suggestion though. You might be able to make a case for early onset muscle assist? Dunno, just spit-ballin'.