Hi S,
I do get where you are coming from because any shift of either C1 or C2 vertebrae, from it’s normal alignment, can lead to a change in cerebro-spinal fluid (CSF) dynamics – and subsequently raised intracranial pressure. I’ve heard of the NUCCA chiropractic method before and, although EDSers have to be very careful indeed, it may turn out to be just what you need. In the meantime, as Dr Diana says, the Diamox could be very useful.
Don’t forget that the affects of persistent raised intra-cranial pressure may show up on an Eye Fundus photo, taken by an optician, just a thought. Do let us know how you get on.
Barbara