EEG's & MRI's will only show large fiber disturbances in the tissues.
If these are 'normal' and show no problems, the gold standard for small fiber
damage confirmation is the skin punch biopsy. I have one done every 3-4 years to check on the level of damage.
I've been able to keep it in check without significant additional damage for the last 6-8 years.

My neuro first diagnosed me by saying:
I've good news & bad news.......
the good is that you are continuing to grow new small fibers.
The bad is that your neuropathy/fiber destruction is faster than the new growth.
If we can halt progression, the new may just catch up, someday.

Knowing what type of neuropathy (mine is sensory, length dependent, axonal, small fiber, polyneuropathy) does affect the type of treatment, to some extent.