Had my appointment with the neurologist this morning. He ran me through some tests for things like reflexes, resistance to pressure (on arms and legs), for feeling in the limbs, and the like.
From what he could tell, the twitching isn't neurological. He never even brought up the possibility. He did say that an over-active thyroid might be causing the twitching. I had to get some blood drawn, so the lab can check that out. So I should hear something by Monday or Tuesday next week.
That's definitely a load off my mind, and we'll see what the blood tests reveal.