Hmmm.  Well. the inner ear which consists of the auditory system (cochlea) and
the balance system (semi circular canals, etc) are filled with a fluid that
closely resembles cerebral spinal fluid.  And through the interal auditory
canal (a hard bony channel that runs from the brain to the ear) they are semi
connected.  

There can be build ups of pressure in the fluid in the brain, i.e.,
hydrocephaly, when the lymph system is not allowing the drain off of fluid to
occur.  Children can be born with this condition, and often a shunt is inserted
to try to repair the situation.  New fluids are constantly being produced in
both the ear and the brain to replenish and replace old fluid.  In the fluid
are the nutrients needed by the cells to survive, bathing those delicate
tissues all the time and allowing the transmission of nerve impulses, too.

Now in the ear, there is a duct that is meant to drain off the fluid.
Sometimes this doesn't work very well for some reason, and like in the brain,
fluid backs up and pressure accumulates.  This is called hydrops in the ear.
People can experience sudden increase in tinnitus (most often lower pitched
roaring type) and dizziness and loss of hearing............People can feel like
they have the flu without the fever or the belly ache although they will feel
seasick.

If the pressure builds up enough, it will often rupture one of the delicate
membranes in the ear, or force the fluid thru the duct, and then recovery
slowly begins.  

In cycles, this is often tagged Meniere's Disease and often hearing loss is
progressive and over time, the person can lose up to fifty percent of their
hearing and will need a hearing aid.  

I hope this helps.  In head trauma, the cerebral spinal fluid can travel in the
form of a tsunami or tidal wave up the auditory canal and cause all kinds of
damage to the ear, the balance system, and the hearing............it is a very
good questin.

Another fellow, Marchbanks, postulated that we could tell brain fluid pressure
by measuring ear fluid pressure since they are so related and he was right!
His machine is not well known but it was quite useful before the advent of
fancy imaging technology that has replaced many other older tests.  

We are one beautifully inter-related system of fragile wondrous parts........

Marsha Johnson, M.S.
Director
Oregon Tinnitus & Hyperacusis Treatment Clinic
POrtland, Oregon