Originally Posted by glenntaj

--the more likely possibility is that samples taken from all areas will show intraepidermal nerve fiber density reduction, and that there will not be a pattern of greater reduction in samples taken farther from the center of the body (such as at the ankle) vs. more proximal areas (thigh, upper arm).

In length-dependent neuropathies, it's the fibers that are farthest from the body that show damage first, and that show greater damage as time goes on. this is thought to be due to the fact that much of the damage, whether diabetic, toxic, autoimmune, etc., is thought to be primarily circulatory/ischemic in nature, in that damage to small blood vessels results in nerves not getting enough nutrients/oxygen and being unable to efficiently remove waste products, and the farther this is from the center of circulation, the more likely this is to occur--it takes efficient circulation to do this in tissue in the feet, for instance, where blood also has to fight gravity.