One of the things that we try to do in our lab is, we always wonder, “How can we improve clinical vestibular assessment?” What are the questions? What are the things we need to figure out or work out that are not sorted out yet?
Dizziness and balance problems are really disturbing symptoms. It’s real common for patients with dizziness and balance problems to undergo all of these tests and have all the tests be normal, or not really find out what’s going on with the patients.
What are some of the major trends in vestibular assessment research?
Since the 1960s, most, if not all, vestibular assessment focused on one of five vestibular sensory organs — on the horizontal semi-circular canal. One of the things that happened in the early 1990s was the development of otolith organ tests. There was a lot of emphasis on that, and we were able to measure the vestibular evoked myogenic response, either off of the neck muscles or by placing electrodes on the face and measuring the extraocular muscles.
That allowed, that was the development of otolith testing. More recently, with better quality technological advancements in terms of video cameras and the speed of video cameras, and the light-weight video cameras we’re able to use video goggles — for video head impulse tests for example.
The information and the development of vestibular assessment has really grown in the last 10 years. So we have a lot more tests that are available and that are newly FDA-approved. So you’ve got to make some decisions about which ones are you going to use. That’s where a lot of our work has focused. And we don’t really have the data to tell us which tests we should be using yet. In fact, one of the things that we’re seeing is that we might have three tests that test the same part of the inner ear, but they might all show different findings. So which one is the relevant test? It really matters when you think about the cost of testing those patients and the patients’ time.
What are the main considerations when “testing tests”?
We want to look at the sensitivity and specificity of these different measurements of vestibular function and try to get a handle on what a vestibular protocol should look like. And what are some clinical guidelines — help develop some clinical guidelines that would direct audiologists in terms of which vestibular tests should be used with which patients, and what is the clinical utility of these vestibular tests. We know this for some of them, but now that we have new tests, we don’t really know if they’re going to replace some of the very old tests, so we have to design some experiments to find out some of those answers.
How are you approaching these questions in your lab?
I’ll tell you what we’re doing right now is we have data from about a thousand patients on two different tests, and so we’re starting retrospectively to look at our data — in about a thousand patients trying to determine what types of patterns do we see. What we really need to do is link those tests, I think, with quality of life measures and functional measures such as posture and gait — is there any relationship between what we find on these vestibular end organ tests to posture and gait measures. Those are some of the things that we’re trying to do in our lab, now.
What’s the future of vestibular assessment?
I’m really curious about what the vestibular clinical test battery is going to look like. That’s one thing that I’m excited about. Again, we’ve had mainly one test that we’ve been using to assess vestibular function since the 1960s or 70s, the caloric test, and now we have all of these tests that are available, and trying to make some decisions. I’m curious about where that’s going to end up — and if we’re going to end up with the same test that we’ve had. Maybe we learn that test really was the best test. Or maybe we have these other tests that either supplement or replace that test.
So we need research to shape some of those decisions.