GrannyJo, I'm sorry for all you're going through.
There are a lot of things that can cause a positive Romberg Sign.
http://www.jpgmonline.com/article.as...aulast=Khasnis
Did they test your B12 levels?
Ditto on what Abby said about the tests going negative. Have they retested your antibody levels?
You could have a lesion. That's quite possible.
Going off of IVIG doesn't seem really sensible. It's sort of like a mad scientist experiment.
Be prepared for them to suggest a lumbar puncture at some point.
Here is some basic info for you.
http://www.neuroexam.com/neuroexam/content.php?p=32
http://www.dartmouth.edu/~dons/part_1/chapter_8.html
I hope you get some answers soon. I can't imagine how tough it would be to not be able to swallow.
Annie