They measure how long it takes for a sensory impulse to make it up to the brain, and are generally not used to just make a diagnosis of pn, but to make a diagnosis of multiple sclerosis, or something wrong in the cord. neuropathies of large fiber sensory nerves can make this test abnormal. I think most people with sensory neuropathy will have normal SEPs.

I had them done, and I think they were looking to see if the nerve tracks which give information for balance were impaired. They were not. They are in B12 deficiency states.

So, my guess is they are looking for MS. Which is what you are concerned about, right?

http://www.emedicine.com/neuro/topic344.htm