I don't know the proper terms, but the length dependant has something to do with the distance from the CNS. Feet & hands are at the greatest length or distance.
Demyleinating is when the myelin sheath is deteriorating. Many small fibers don't have a sheath, just an axon- so.... 'axonal' rather than "demyelinating".

Treatment?
Just meds and supplements is all they (at Hopkins) seem to be able to do for my problems. I sometimes think that I've been more instrumental in my aggressiveness to my treatment, than they have.