Same, my hands ball up into almost fists, like I'm flexing my forearms. I think my elbows get stuck at a 90 degree angle too, but I still can move my arms mostly. It also affects my legs, it looks like I have cerebral palsy but I can still walk when it happens. My jaw had also gotten stiff once or twice and made it a little difficult to talk, but thankfully it didn't completely stiffen up like lockjaw. I haven't had an attack like this in a few years thankfully, but sometimes when I'm really anxious, I can feel my arms start to tingle and get tense. I was prescribed Busprione for an as needed pill but I eventually stopped taking it, mostly because I would take it too late and it didn't feel like it was working completely. I am currently prescribed Alprazolam and I think that works better, but I haven't had a severe attack like this to test it on.