Caloric stimulation is a test that uses differences in temperature to diagnose damage to the acoustic nerve. This is the nerve that is involved in hearing and balance. The test also checks for damage to the brainstem.
This test stimulates your acoustic nerve by delivering cold or warm water or air into your 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. The test is done in the following way:
During the test, the health care provider may observe your eyes directly. Most often this test is done as part of another test called electronystagmography. In this case, patches called electrodes are placed around your eyes to detect nystagmus. A computer records the results.
Do not eat a heavy meal before the test. Avoid the following at least 24 hours before the test, because they can affect the results:
But do not stop taking your regular medicines without first talking to your doctor.
During the test, you may:
This test may be recommended if you have:
It may also be done to look for brain damage in persons who are in a coma.
Rapid, side-to-side eye movements should occur when cold or warm water is placed into the ear. The eye movements should be similar on both sides.
Abnormal results mean:
Abnormal results may be due to:
The test may also be done to diagnose or rule out:
Too much water pressure can injure an already damaged eardrum. This rarely occurs because the amount of water to be used is measured.
Water caloric stimulation should not be done if the eardrum is torn (perforated). This is because it can cause an ear infection. It also should not be done during an episode of vertigo because it can make symptoms worse.
Caloric test; Bithermal caloric testing; Cold water calorics; Warm water calorics; Air caloric testing
Baloh RW, Jen J. Hearing and equilibrium. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 436.
Kerber KA, Baloh RW. Neuro-otology: diagnosis and management of neuro-otological disorders. In: Daroff RB, Fenichel GM, Jankovic J, Mazziotta JC, eds. Bradley's Neurology in Clinical Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 37
Updated by: Ashutosh Kacker, MD, BS, Associate Professor of Otolaryngology, Weill Cornell Medical College, and Associate Attending Otolaryngologist, New York-Presbyterian Hospital, New York, NY. Review provided by VeriMed Healthcare Network. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Blackman, Stephanie Slon, and Nissi Wang.
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