No wonder you want definition, i don't blame you one bit.
If i am reading this right, when the neuro done the normal pin prick to test how your small nerves react and found then it was abnormal below your ankle then it really surprises me that they didn't do Quanitive Sensory testing in the next step of testing to confirm more evidence of small fibre damage, but finding the cause isn't always so easy as you probably already know.

Ideopathic Hypersomnia ??? what about Lyrica's possible side affects can cause problems with memory or concentration, tiredness & Vicodin is another that can cause side effects that may impair your thinking or reactions and warn to be careful if you drive or do anything that requires you to be awake and alert, so any wonder you feel tired enough to ask about stimulants, you would think that that doc would have explained those possible side affects of the medication you have to take, without saying to you your request was ludicrous, some of the medical people are defiantly in the wrong job, and believe me i have a found a lot of them in the time i had PN.

I hope you get definition of your problem and especially find the cause.
good luck
Brian