WAIT
I KNOW THIS ONE
My late mother had this: Benign essential tremors
Basically means your thalamus is screwed up
They're not life threatening; they just really suck
Head & hands shake like crazy and it gets worse and worse
Mom couldn't hold a pen or use a keyboard
If something made her nervous, it got even worse
Treatment options - there are two
DBS - deep brain stimulation - they put an electrode in your thalamus
Only my mother didn't do that, she just took benzos
She liked benzos so much that she was two-timing two different neurologists for two Rxs for them
Ended up in rehab to taper off them
WTF, I grew up in the 70s and was supposed to be the one on drugs but NOOOOO
So pretty much if that's it, Susan needs to get the DBS procedure, she'll be glad she did it
https://www.webmd.com/brain/essential-tremor-brain-stimulation#1