i would follow thru with this dr since he is willing to run a few more tests.
IF you have an LP make sure it's done by a radiologist and is done under floroscopy. that's a machine that shows the dr where the needle is. i had one and it went very well. some people don't but i think a lot do. we'll cross that bridge when we come to it.

after you've done what he wants consider getting a 2nd opinion. i am a strong advocate of the 2nd opinion when you're looking at getting a serious dx (diagnosis) or when you have a serious disease. it never hurts. especially if you are not certain of your current dr's expertise.

you can call your local MS society (1-800-FIGHT MS) and they'll send you info on MS and give you dr referrals. it's a start.

please keep us posted.