When the head rotates or tilts, the otoliths in the vestibule sacs shifts, causing the fluid in the semicircular canals to move, bending hair cells, which turn in activate neural signals and notify them about the head's position and movement. The vestibule nerve connects with the cochlear nerve to form the auditory nerve, which relays information to the brain about balance.
I believe she has the Ppo plan. Ppo plans allow you to visit whatever in-network physician or healthcare provider without first requiring a referral from a primary care physician.