The most common areas for me are the thighs, thumbs (the webbing between
the thumb and
pointer fingers), calves, triceps, and
abdomen. If I'm busy, whether physically or mentally, I don't notice the twitching as much. Once I sit down in the evening, I twitch constantly. My left tricep will twitch then two seconds later my right thigh will twitch, then another body part, etc... Also, it is usually only one spasm.
I'm fairly certain I have had every diagnostic test performed.