From everything I have read, I find all symptoms for SFN to be sensory and autonomic. For almost a year, I have twitching in random parts of my body coming and going all day. Sometimes they are strong and slow and sometimes very fluttery and fast. I have terrible muscle spasms in my neck and shoulders which seem to throw my whole cervical and thoracic spine surrounding muscles into a crisis. I have had the complete spine and brain MRI, but my muscle symptoms are not consistent with SFN. My doctor has be diagnosed on paperwork with progressive polyneuropathy and he is very mild with treatment (which I like and don't like). I caught a bunch of the crazy twitching on my phone video and showed him and he just said "Hmmm". I think he knows more than he tells me, but doesn't want me to lose hope.