First of all, keep in mind that I am unable to diagnose you because I am unable to examine you, this forum is for educational purposes.
The symptoms you describe do not sound like "mini-strokes" or moya-moya disease (a devestating condition with progressive vascular occulsion of all the vessels in the brain). I would agree that the most likely explanation given the symptoms you describe is anxiety/ possible conversion disorder, but I would also be in favor of testing to rule out ominous causes first. I do not know what "lot of tests" the neurologist ordered, but I would suggest an MRI of the brain with contrast and an EEG (elctroencephalogram-or brain wave test). I would also suggest a migraine preventative medication (such as elavil, topamax, zanaflex, nadolol, etc..) taken daily to see if this sensation could be related to migraine headaches (you do not need to have the headache part).
I hope this has been helpful.
You may want to ask your friend if she had any dental work recently or at any time. Ask her look into her mouth if she has silver fillings, crowns, bridges. Google " symptoms of mercury fillings"
"safe removal of silver fillings"
If she does have silver fillings and want more information she may go the DAMS website google "Dental Amalgam Mercury Syndrome" their #DAMS National Office at 1-800-311-6265.
Cheers