One teaspoon of cold water is gently instilled in the ear canal with a bulb syringe. At times, hot water may be used in addition to cold water. Use of both cold water and hot water makes the test more accurate. 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. There is minimal discomfort.
Some people find cold water in the ear uncomfortable.
Brief, but severe vertigo may occur during the test. Excessive water pressure can injure a previously damaged eardrum, but this rarely occurs, since the amount of water is measured. Caloric stimulation should not be performed if the eardrum is perforated because of the risk of causing ear infection . 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. If nystagmus does not occur even after 8 teaspoons of water are instilled, it may be assumed that there is permanent damage to the nerve.