Caloric stimulation

Alternative names:

caloric test

How the test is performed:

Each ear is tested separately. One teaspoon of cold water is gently instilled in the ear canal with a bulb syringe. This should cause nystagmus (quick movement of both eyes away from the direction of ice water and then slowly back). If it does not cause nystagmus, 2 teaspoons of cold water are instilled in the ear canal. If nystagmus still fails to occur, 4 and then 8 teaspoons of cold water are used.

At times, hot water may be used in addition to cold water. The nystagmus should occur in the opposite direction (toward the hot water then slowly away). Use of both cold water and hot water makes the test more accurate.

How to prepare for the test:

Adults:
No special preparation is necessary.

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:

• infant test or procedure preparation (birth to 1 year)
• toddler test or procedure preparation (1 to 3 years)
• preschooler test or procedure preparation (3 to 6 years)
• schoolage test or procedure preparation (6 to 12 years)
• adolescent test or procedure preparation (12 to 18 years)

How the test will feel:

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

Why the test is performed:

Caloric stimulation is performed to evaluate the acoustic nerve, which provides hearing and helps with balance. This test may be recommended when the person is experiencing dizziness or vertigo, when there is impaired hearing, with suspected toxicity from certain antibiotics, with some anemias, when psychologic causes of vertigo are suspected, and to determine the presence or extent of brain damage in a comatose person.