Caloric stimulation is a test which uses differences in temperature to diagnose ear nerve damage.

This test stimulates the inner ear and nearby nerves by delivering cold and warm water to the ear canal at different times. Sometimes, the test is done using air instead of water.

One ear is tested at a time.

When cold water enters the ear, it should cause rapid, side-to-side eye movements called nystagmus. The eyes should move away from the cold water and slowly back.

Next, warm water is placed into the ear. The eyes should now move towards the warm water then slowly away.

Patches called electrodes, placed around the eyes, detect the movements. A computer records all the results.

Ice cold water may be used if there are no responses.

Do not eat a heavy meal before the test. Avoid caffeine, alcohol, allergy medications, and sedatives at least 24 hours prior to the test, as these can affect the results. (However, do not stop taking medicines without first talking to your doctor.)

Some people find cold water in the ear uncomfortable. Brief, but severe vertigo may occur during the test.