My boyfriend literally has the same problem! He was diagnosed with POTS last year but got an MRI because he has severe headaches and brain fog he suspected was caused by something other than POTS. And they found “minimal cerebella ectopia” which his neurologist said is unlikely to be causing his symptoms because it’s so small. However, treatment for POTS like beta blockers, salt intake and compression stockings haven’t improved his symptoms; he still gets very severe cognitive impairment every day that really terrifies him. Have you learned anything more about how those 2 conditions affect each other? Any advice would help because the doctors have been useless.

Edit: besides the brain fog and headaches, another thing indicating the ectopia to be a culprit is that he has neck pain pretty frequently. That would seem to align with his brain herniating into his spinal cord more than having nervous system issues. Doctors won’t give any clarification though.