I did. The neuromuscular specialist who is a member of an *** clinic told me my reflexes were "brisk but normal for a person of my age" (and importantly all the reflexes that you shouldn't have, I didn't have) and that she could not elicit any muscle weakness -- and she did a quick but thorough exam.
She also held and watched my limbs and didn't see or feel a single fasic, despite the fact that I can feel them and my PT does, too. I guess my muscles were just afraid to act up around the "expert"
I asked about my hand specifically as I thought for sure I had atrophy in one specific muscle, and sometimes I can't get my BBQ lighter to go. She checked twice and said, my thumb is "slightly" weak but the fact that I can somewhat resist a push, and that the index finger isn't at all weak, is a good sign; then she said if anything that hand was bulkier in muscle overall, and she thought the difference in the musculature that I was noticing might be due to swelling around my CMC joint, which, now that she's pointed it out, acts and hurts in a way that certainly looks a heck of a lot like boring old arthritis. Then I asked about a bunch of pain I had in that wrist on dorsiflexion/loading and she said yeah, that sounds more like injury + nerve compression, come back if it's worse and she'll redo an NCS on that wrist for me.

Sidenote: I have since learned I have been trying to use a BBQ lighter wrong my entire life (you have to push *down* on the slidey bit before pushing it forward and squeezing the trigger, who knew?! )

Last, the specialist told me: Look, bodies twitch in response to stress. Any stress. Physical, mental, emotional, even things like being too hot, too cold, hungry, thirsty. Then she asked me "what were you afraid of when you came in today?" She made me name it. Then she told me I have no signs of that. None.

Meanwhile, my pain and numbness in my right leg have vanished with PT, and my speech/tongue/bite have stopped being weird and my middle ear myoclonus tinnitus magically disappeared after 1) I had a real (minor) household med emergency 2) got a miraculous night of good sleep 3) firmly told it off in the style of another poster in this forum who is also simply fed up with their twitching. Really! I literally told myself one night, "nope, I am not doing this tonight. I'm going to sleep."

Am I cured of my HA? No. My gait still feels really off and my right leg is stiff and *explodes* in fasics the instant the PT start stretching it (he insists this is normal and I am trying to trust him -- also, like, I DO have a degenerated disc, slight scoliosis, and a lot of metal and enough screws to shingle a roof in the opposite leg, so... it IS entirely possible that what I am noticing is simply that I have two very different legs, the more "reliable" of which has now been over-relied upon, developed a nerve root compression, and is annoyed.) Weirdly, though, even this waffles around: some days it's better, other days worse, depending on what my PT has done to me lately.

I am worrying less, but I think it would take a clean EMG for me to be able to evict this thing from my mind completely. I have a rule about my HA, though: I only get to worry about things in 6mo increments. And now that I have been cleared by an *** specialist, it's time to remove this from the list for 6mo.

Wishing you all the best. One major piece of advice: STOP TESTING. Immediately! You *will* only make it worse, especially if you, like so many of us here, start doing weird stuff like trying to pour from a gallon of milk with your index finger alone or jack up a Land Rover with your tongue or whatever it is the internet says will "prove" you're not "weak." And then you *will* hurt yourself and you'll be unable to use a doorknob the next day and your brain will go *splat* with anxiety. So, really, just don't test anything!!!

& keep us posted, it'll help the next poor twitcher...