What is caloric stimulation?
Caloric stimulation is a procedure used to find damage to
nerves in the ear. Although people commonly associate the term calorie with food,
a calorie is fundamentally a unit
of heat. During caloric stimulation, cold and warm water are placed into your
ear canals and your reaction is monitored.
Other names for caloric stimulation are caloric reflex test, cold water
calorics, and warm water calorics.
caloric stimulation is performed
This test checks the function of your acoustic nerve,
which is involved in hearing and balance. It also evaluates the function of
brain areas involved in balance.
Caloric stimulation is used to evaluate:
- hearing loss caused by antibiotic use
- vertigo (dizziness)
- psychological causes of vertigo
- brain damage in comatose individuals
is caloric stimulation performed?
Caloric stimulation is performed by inserting first cold and then warm water
into the ear canals. This is done one ear at a time. The water stimulates the
nerves of the inner ear.
Caloric stimulation usually follows these steps:
1. The eardrum is checked
Before the test the eardrum is checked to make sure it is
healthy and not perforated. Inserting water into an ear with a compromised eardrum
could lead to an ear infection.
2. Electrodes are placed
Electrodes are placed around the eyes and connected to a
computer. The electrodes are used to measure eye movement during the test.
2. Cold water is inserted into ear canal
A small amount of cold water is inserted into the ear canal.
This changes the temperature of the inner ear and causes rapid, side-to-side
eye movements called nystagmus.
The cold water causes the eyes to move away from the direction of the cold
water, and then move slowly back.
3. Warm water is inserted into ear canal
Warm water is then inserted into the ear. This time, the
eyes should move toward the warm water, and then move slowly back. The test is
then performed on the other ear.
4. Eye movements are monitored
Eye movements are detected by the electrodes and recorded by
the computer. Sometimes the person conducting the test visually observes the
involved with caloric stimulation
The test may cause some minor discomfort, especially when cold water is
inserted. The test may cause brief feelings of vertigo, which can lead to
nausea in some people.
Although rare, it is possible for excessive water pressure to injure an
eardrum. For this reason, only a small amount of water is used for this test. An
injury is more likely to occur if the eardrum has been previously damaged. Your
doctor should check your eardrum before the procedure, and this test should not
be used if it is damaged.
for caloric stimulation
Some foods and medications can affect your test results. For 24 hours before
your test, you should avoid consuming the following:
- large, heavy meals
- allergy medications
Talk to your doctor about what medications to avoid before the test. Never
stop taking your medication without your doctor’s approval.
Caloric stimulation results
Normal results mean that you do not have damage to your acoustic nerve.
If your eye movements are abnormal, it may be a sign of acoustic nerve
damage, damage to the balance sensors in your ears, or brain damage.
Causes of abnormal results include:
- blood clots
- atherosclerosis leading to poor blood supply to the ear
- some poisons
- blood vessel disorders
- ear tumors
- congenital disorders
Ear nerve damage can also be caused by certain medications, including:
- antimalarial medications
Results from this test can also be used to rule out or confirm diagnoses,
- Meniere’s disease
- acoustic neuroma
- benign positional vertigo
Caloric stimulation is a test used to check for damage to your
acoustic nerve, which could be caused by various medical disorders and
diseases, or by certain medications. Abnormal results may point to acoustic
nerve damage, damage to the ear’s balance sensors, or brain damage. Be sure to
discuss the results of your test with your doctor, and ask any questions you