Caloric Test for Dizziness - What to Expect
If you have a suspected inner ear problem that affects your balance and makes you dizzy, caloric testing can help provide a more definitive diagnosis. So, what does the test involve?
In this article, I will provide an overview of how this test works, and will also share my own experience with the procedure. In doing so, I hope to educate others about what to expect.
What is a caloric test?
The test is used to see how the horizontal, semi-circular canal of the inner ear reacts. It can only establish function of this part of the inner ear. In simple terms, first warm water, and then cool water, is flushed into the outer ear. (Some test facilities use air instead of water.) The different temperatures cause changes within a healthy inner ear, due to convection. This results in a sensation of vertigo, and involuntary rapid eye movement, called nystagmus. The patient wears monitors, known as Frenzell goggles, to record eye movement. Results can later be studied. Sometimes, instead of goggles, electrodes are places on the face for this recording.
If the inner ear is damaged by a virus, trauma, or circulation problems, results reflect this. Recovery can then be helped by treatment with vestibular rehabilitation therapy. For more scientific information about the test, please see Dr. Timothy Hain's description (Dr. Hain, known as the "Dizzy Doctor," is a professor emeritus at Northwestern University Medical School).
In the following video, medical students observe a colleague having the caloric test to follow his eye movement.
Nystagmus induced by caloric testing
My experience of the caloric test
I'd been having balance problems for a long time, and was finally being sent for tests. When my appointment arrived, it came with instructions to avoid medication and alcohol for 48 hours prior to testing. This is to ensure nothing interferes with the results. The letter also advised having someone with you, and not driving yourself, as the test is likely to make you dizzy.
I've always had a thing about water in my ears - absolutely hate it, so this was not something I was looking forward to. If the water trickled down my neck, I'd have to grit my teeth and concentrate on not leaping off the couch.
Before the caloric test, which was part of a series of testing, my eardrums were checked to make sure there were no perforations or infection. Next, I was fitted with Frenzell goggles, then lay down on the couch. The technician, a friendly lady, placed a small dish behind my right ear. She said my ears were a perfect fit for the dish, which luckily meant no water splashing around.
Water was squirted into the ear, while my eye movements were being recorded. It's important to keep your eyes open if you're wearing the goggles. I had a weird tingling sensation down my leg as the water went in, and did feel the room start to spin. The technician shone a torch into my ear to ensure it looked pink, meaning the warm water had reached deep into the ear.
Once the room stopped spinning for me, the technician moved to the left ear. The process was repeated. It didn't seem to have as much effect, again my ear was checked for pinkness. Although I was dizzy, I did feel more relaxed about the proccess once it was underway. The sensation of having water poured into my ears wasn't nearly as unpleasant as expected.
Now came the cool water. The right side test made the room spin incredibly. Again, my leg tingled. I clung on to the couch. The technician asked if I was nauseous - fortunately not. Another wait until things settled, then the left ear was tested. Very little response. The lady re-did the test in case the water hadn't hit the right points, with the same outcome.
I was freed from the monster goggles and allowed to sit up. Boy, the room spun. The technician said I could go, but actually, I couldn't. Every time my feet touched the floor, it felt like the ground was being whipped away from under me. It took several minutes sitting very still before I dared stand up, and was helped back to the waiting room.
Following the caloric test
The next couple of days were a bit lousy; my challenged balance system protested. I was dizzy and tired. This can happen to me anyway, but it did seem the testing had been a strain. Things gradually settled down.
A month later, at the next hospital appointment, results had been studied. It showed a 40% loss of balance function on the left side. I was offered vestibular rehabilitation therapy, (VRT,) to aid recovery, and given an explanation of how a faulty balance system impacts on other parts of life. It was a relief to be offered treatment.
It can be difficult to diagnose balance problems. I found it helpful to finally have an explanation, and know I hadn't been imagining things. So, the testing was worthwhile. I wouldn't volunteer for another go, but neither would I run a mile.
If you are advised to have this test, think of the long term benefits, possible rehab treatment, and try not to worry too much. It's a safe procedure, and can be useful for diagnosis.