I've never heard of them either.
My relapses cause me to pass out. For years the docs thought it was just an allergic reaction to bug bites. I even carried an epi pen for almost 10 years. Then someone that saw me pass out said it looked like I was having a seizure...which brought on the brain MRI...the MS diagnosis came quickly after that.
MRIs seem to be critical to diagnosing MS. Have you had one? Do you have lesions on your brain or spine?