To augment Glenntaj's referral to LizaJane's tests and exams tho... You first have to understand what neuro's test for and why: http://www.neuroexam.com/content.php?p=2
This will help a bit in explaining that there are soo many different aspects to neurology that diagnosis is often not simple at all.
Then take a look at just the different types of neuropathies that there are:
http://neuromuscular.wustl.edu/alfindex.htm
Well, that embraces a LOT of issues just relating to neuropathies!
Have you been thoroughly checked out for both diabetes [a 3+ hour glucose tolerance test-at least] and also for any possible thyroid or endocrine [mainly thyroid] issues? How thoroughly have the gluten aspects been tested and also WHY only an MRI only of the brain? You could have fallen and not realized that something is now pinching in your spine and a zillion other issues.
Cognitive issues can occur with other neuro issues besides MS, I had them to a degree with my own neuro onset. And other factors could be causing the cognitive problems.
You have done a good summary and I'd copy that for your neuro appointment. You are giving him a summary of WHAT is going on with you that is not NORMAL! The neuro may focus on only one or two things he feels he can deal with? Or take it in as a whole. Don't assault the doc to 'make you well', tho...that never works. But, a GOOD neuro will try to help you work with whatever problems are diagnosed [if you are lucky] and find you the help to work around them.
I will bet you that your doc is going to order lots, LOTS more tests! Bring a notebook with you to keep track and ask for copies of the lab and other test reports... depending on what state you live in, they can be had for free or for a small charge of say $10. From what you have written? It does seem as if your neuro is the usual cautious, but at the same time a bit pro-active in the encouragment to start the Vit-D and all.
I hope this helps? Do read the 'Sticky' important information at the top of the page...it's lengthy, but it covers a lot of the neuropathy universe.
Please don't automatically think that you have MS! Some PN's are treatable, but it takes a LOT of time to heal those literally frazzled nerves. Others are not and the subject is complex and does often overlap with MS and endocrine and cardiac and nutritional issues to a huge extent.
Read up on posts by DarlinDeb as she has Celiacs and how it has affedted her neuropathies...
Keep faith and hearth in yourself to get this tended to and now go and hug those kids of yours! 's - j