热量的刺激

定义

热量的刺激 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 brain stem.

选择的名字

Caloric test; Bithermal caloric testing; Cold water calorics; Warm water calorics; Air caloric testing

如何执行测试

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, 应该会很快, side-to-side eye movements called 眼球震颤. The test is done in the following way:

• Before the test, your ear, especially the eardrum, will be checked. This is to make sure it is normal.
• One ear is tested at a time.
• A small amount of cold water or air is gently delivered into one of your ears. Your eyes should show an involuntary movement called 眼球震颤. 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, your eyes should show 眼球震颤. Then they should turn toward that ear and slowly back.
• Your other ear is tested in the same 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 他院求诊.

How to Prepare for the Test

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:

• 酒精
• 过敏药物
• 咖啡因
• 镇静剂

Do not stop taking your regular medicines without first talking to your provider.

考试的感觉如何

You may find the cold water or air in the ear uncomfortable. You may feel your eyes scanning back and forth during 眼球震颤. 你可能有 眩晕, and sometimes, you may also have nausea. This lasts only a very short time. 呕吐很少见.

为什么要进行测试

This test may be used to find the cause of:

• 头晕或眩晕
• Hearing loss that may be due to certain antibiotics or other drugs

It may also be done to look for brain damage in people who are in a 昏迷.

正常的结果

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.

异常结果意味着什么

如果快速, side-to-side eye movements do not occur even after ice cold water is given, there may be damage to the:

• 内耳的神经
• Balance sensors of the inner ear
• 大脑

Abnormal results may be due to:

• Poor blood supply to the ear
• 出血(出血)
• 血凝块
• 大脑或脑干损伤
• 胆脂瘤 (a type of skin cyst in the middle ear and mastoid bone in the skull)
• Birth defects of the ear structure or brain
• Damage to the ear nerves (from infections such as rubella or from medicines)
• 中毒
• 中风
• 创伤

The test may also be done to diagnose or rule out:

• 听神经瘤 (tumor of the acoustic nerve)
• 良性位置性眩晕 (头晕的一种)
• 迷路炎 (irritation and swelling of the inner ear)
• 梅尼埃病(又名内耳眩晕 (inner ear disorder that affects balance and hearing)

风险

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 耳朵感染. It also should not be done during an episode of 眩晕 because it can make symptoms worse.

参考文献

Baloh RW, Jen JC. 听力与平衡. In: Goldman L, Schafer AI, eds. Goldman-Cecil医学. 26日艾德. Philadelphia, PA: Elsevier; 2020:chap 400.

Kerber KA, Baloh RW. Neuro-otology: diagnosis and management of neuro-otological disorders. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8日艾德. Philadelphia, PA: Elsevier; 2022:chap 22.