Caloric Stimulation Test
Tests & Procedures

What Is Caloric Stimulation Test And Why Is It Done?

A caloric stimulation test is a process used to discover damages to nerves present in the ear. This test makes use of changes in temperature to detect damage to the acoustic nerves in the ear. Said this let us see how it is done.

What Is Caloric Stimulation?

As said above it is a procedure to check for damages in the ear especially the hearing capacities. Through caloric stimulation, warm and cold water are put into the ear canals and the reaction is examined. The other names include caloric reflex test, warm water calorics, and cold water calorics.

What Is A Caloric Stimulation Test?

A caloric stimulation test is a test used to check damages to the acoustic nerve which is responsible for hearing and balance. The test is also used to check for damages to the brain stem.

Why Is The Caloric Stimulation Test Done?

It is performed to check the function of the acoustic nerve which is engaged in hearing and balance. It is even done to evaluate the function of brain regions involved in balance.

The other reasons why it is done include;

  • Hearing loss due to antibiotic usage
  • Vertigo (dizziness)
  • Psychological reasons for vertigo
  • Brain damages in comatose individuals

How Is The Test Done?

It is done by injecting cold water followed by warm water into the ear canals. This process is carried in 1 ear at once. The dropped water stimulates the nerves present in the inner ear.

Usually, caloric stimulation follows the below steps;

1. The Eardrum Is Examined

Before the test, the eardrum is examined to ensure it is healthful and not unhealthy. This is done because pouring water into ears that have damaged eardrums can cause ear infections.

2. Electrodes Are Put

Around the ears, electrodes are placed and linked to a computer. These electrodes are placed to calculate eye movement in the course of the test.

3. Coldwater Is Placed Into The Ear Canal

A small quantity of cold water is injected into the ear canal. This modifies the temperature of the interior ear and leads to rapid, side-to-side eye movements known as nystagmus. The cold water makes the eyes move away from the direction of the cold water and again moves them back slowly.

4. Warm Water Is Injected Into The Ear Canal

After cold water warm water is inserted into the ear. When this happens eyes should move towards the warm water and then move away back slowly. The same process is also done on the other ear.

5. Eye Movements Are Examined

The electrodes check the eye movements while the computer records the movements. Sometimes the examiner also monitors the eye movements visually.

How To Prepare For The Test?

Some medicines and foods affect the test results. Before a day of the test, you must avoid having the below;

  1. Big, heavy meals
  2. Alcohol
  3. Sedatives
  4. Caffeine
  5. Allergy medicines
  6. Also, know which medicines should not be taken from your doctor.

Caloric Stimulation Test Results

Normal Results

Normal results connote that you don’t have any damages to your acoustic nerve.

Abnormal Results

If the eye movements are irregular, it could be a signal of acoustic nerve injury, injury to the balance sensors in the ears, or brain damage.

The reasons for abnormal results comprise;

  • Trauma
  • Atherosclerosis causing the poor blood supply to the ear
  • Blood clots
  • A few poisons
  • Blood vessel illnesses
  • Hemorrhage
  • Rubella
  • Congenital disorders
  • Ear tumors

Ear nerve damage can even be due to a few medicines including;

  • Diuretics
  • Antimalarial medicines
  • Antibiotics
  • Salicylates

Results from this test can even be used to validate the below;

Risks Associated With Caloric Stimulation

The test could lead to a few minor discomforts, particularly when cold water is injected. The test could even cause small moods of vertigo, which may cause nausea in a few people.

Although unusual, it is probable for too much water pressure to hurt an eardrum. For this cause, only a little quantity of water should be used. Damage is more supposed to happen in case the eardrum has damage previously. A doctor will check the eardrum before the process and this test must not be conducted if the eardrum is damaged.

If you feel you are having hearing issues it is better to go for this test after consulting your doctor.