A caloric test uses differences in temperature to diagnose damage to the acoustic nerve, which is involved in hearing and balance, in the ear. The test also checks for damage to the brain stem.

This test may be used to find the cause of:

• Dizziness or vertigo
• Hearing loss that may be due to certain antibiotics or other drugs

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How does it work?

The caloric test stimulates the acoustic nerve by delivering cold or warm water or air into the ear canal. When cold water or air enters your ear and the inner ear changes temperature, it should cause fast, side-to-side eye movements called nystagmus.

• Before the test, the ear and eardrum will be checked to.
• One ear is tested at a time.
• A small amount of cold water or air is gently delivered into one of the ears. The patient’s eyes should show an involuntary movement called nystagmus. Then they should turn away from that ear and slowly back. If water is used, it is allowed to drain out of the ear canal.
• Next, a small amount of warm water or air is gently delivered into the same ear. Again, the eyes should show nystagmus.

During the test, the physician should observe the patient’s eyes for movement.

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What can I expect after treatment?

Patients may find the cold water or air in the ear uncomfortable. They may feel their eyes scanning back and forth during nystagmus. Vertigo and nausea can occur but last a short time. Vomiting is rare.