The Inner Ear
To understand dizziness and vestibular disorders, it helps to know a little
about how the inner ear works.
The inner ear contains both the cochlea, which is responsible
for hearing, and the vestibular system, which provides your brain with important information about movement and your position in space.
The short version: Your inner ears detect head movement and gravity, helping your brain keep you balanced and your vision stable as you move.
Five sensory organs help us detect movement and gravity.
Each inner ear contains three semicircular canals and two otolith organs:
the utricle and saccule.
Together, these structures detect different types of head movement and
continuously send information to the brain about where the head and body
are in space.
Detecting rotational head movement
Each inner ear has three semicircular canals:
horizontal, anterior and posterior.
They sit in different planes and detect angular or rotational movements
of the head, such as turning your head from side to side, looking up or
bending down.
Their different orientations allow the vestibular system to detect
movement in multiple directions.
Detecting gravity and linear movement
The other two vestibular organs are the
utricle and saccule, collectively known as the
otolith organs.
These organs respond to gravity and linear acceleration, helping us
detect movements such as travelling forwards or backwards, moving
side-to-side and moving vertically.
Starting or stopping in a car, travelling in a lift or tilting your head.
Your inner ears don’t work alone.
Maintaining balance depends on the brain combining information from
several sensory systems at the same time.
Inner ears
Provide information about head movement, acceleration and orientation
relative to gravity.
Vision
Provides information about your surroundings and helps the brain
understand whether you or the environment are moving.
Muscles & joints
Provide sensory information about the position and movement of your
body, feet and limbs.
Why can an inner-ear problem make you dizzy?
Normally, the vestibular systems in the left and right ears provide the
brain with coordinated information about head movement.
If one side suddenly becomes weaker or sends different information,
the mismatch between the two sides can produce symptoms such as
vertigo, dizziness, nausea or imbalance.
If vestibular function is reduced on both sides, people may instead
experience problems such as unsteadiness or blurred vision when moving.
VESTIBULAR COMPENSATION
The brain can adapt.
When vestibular function changes, the brain can gradually learn to make
better use of the new information it is receiving. This process is known
as vestibular compensation.
It can be tempting to avoid head movement when movement causes dizziness,
but appropriately graded movement is often important for helping the
balance system adapt.
Vestibular rehabilitation
Vestibular rehabilitation uses individually prescribed exercises to
challenge the balance system and support compensation, gaze stability
and balance.
Vestibular symptoms can affect more than your balance.
Balance is normally an automatic process. When the vestibular system is
not working effectively, everyday activities can require much more
concentration and effort.
Physical symptoms
These may include dizziness, vertigo, unsteadiness, nausea, motion
sensitivity or difficulty seeing clearly during movement.
Fatigue & concentration
Constantly working harder to remain orientated and stable can be
tiring. Some people also notice brain fog or difficulty concentrating.
Confidence & wellbeing
Unpredictable dizziness can understandably affect confidence and
cause worry about movement, driving, work, exercise or leaving home.
WHY ASSESSMENT MATTERS
Dizziness does not always show up on a scan or blood test.
Many vestibular disorders are identified through the pattern of symptoms,
clinical examination and specialised vestibular function testing rather
than routine imaging or pathology alone.
Understanding how different parts of the balance system are functioning
can provide useful objective information and help guide appropriate
management.
What can cause dizziness and vertigo?
Dizziness, vertigo and balance problems can have many different causes.
Learn more about some of the common vestibular conditions and how they
may be assessed and managed.