There are other tests you could and should have....and related conditions that should be ruled out....a CINE
MRI to check CSF flow...a
MRI of the complete spine...cervical ,thoracic, and lumbar in addition to a brain MRI.
Then rule out Syringomyelia, ICP (which you had done) POTS, tethered cord,and Ehlers-Danlos. Sleep apnea.....
As for the "normal" tests....get copies of ALL the reports...some Drs do not know what to look for with this condition....