Dr. Baron: REM behavior disorder is a condition that about 50% of the people with Parkinson’s disease get. Also, among those that develop REM behavior disorder and are not showing signs of Parkinson’s disease, about 50% will later develop Parkinson’s. It doesn’t mean you will get it, it means you have perhaps about a 50% chance. Normally during REM sleep, which is your dream sleep, your body shuts down so you just lie there, but what happens in REM behavior disorder is you act out your dreams. People may actually punch their spouse or through themselves out of the bed. Our body is fortunately designed that when we go into dream sleep we just shut down, our spinal cord is giving signals to not move, but those signals are lost in many people with in Parkinson’s disease.
When should people worry about that?
Dr. Baron: Well if you have this condition there are a couple reasons you might see a physician. Often you are referred to a sleep doctor, and the reason you would go see that physician would be to figure out why you’re moving so much in your sleep. But low and behold, what’s becoming more known now is that if you have this condition there is a high likelihood, maybe 50%, that you’re going to go on to either get Parkinson’s disease or a number of other conditions that we know about that are actually rarer than Parkinson’s disease. There’s something in the brain called alpha-synuclein which we now understand is part of the pathology of Parkinson’s disease. So, there’s a chance you have what is called alpha-synucleinopathy, which one of them happens to be Parkinson’s disease.
Is it a game changer?
Dr. Baron: What the eye testing allows us to do is to pick it up earlier and to confirm the diagnosis so from these standpoints, arguably it is a game changer. When we have therapies in place that slow down Parkinson’s disease, the eye testing will allow us to identify who should be started on them hopefully well before the motor symptoms are apparent. Even if these therapies do not completely prevent the disease, at least if we can identify those at risk and can start slowing it down 10 or 20 years before they start showing symptoms that’s going to have a huge impact compared to waiting until the disease has progressed to the point that they are starting to shake. Also, even if they are showing clinical features such as shaking, they might be misdiagnosed, so it would be important to routinely do the eye testing and establish that it’s really Parkinson’s disease. Many patients are misdiagnosed. We have people that occasionally come in that have been misdiagnosed for up to even 10 years. They’re coming in being pushed in a wheelchair because they were misdiagnosed. If the eye testing had been used routinely to screen these people, it would have proven they had Parkinson’s disease and they wouldn’t have been in that wheelchair. The therapies we have now do not yet slow the disease down but critically will for the most part keep people mostly out of a wheelchair. We also regularly see people who are misdiagnosed as having Parkinson’s disease when the do not and the eye testing could have guided the physician towards another diagnosis.
How long do you think it will take for something like this to be in a doctor’s office?
Dr. Baron: First you have to get past skepticism. I presented a poster of our findings at a conference, the one in Ireland. Although there were many scientific sessions emphasizing the critical need for the means to diagnose Parkinson’s disease presymptomatically, our work was not mentioned. This was perhaps because they didn’t know about it. There were more than a thousand abstracts at the conference and ours simply may not have caught the attention of enough people.
Do you think it’s hard to believe because it is such a debilitating disease and such a simple concept?
Dr. Baron: Yes, I think that’s one of the problems. First of all people have to see it and so unless you see it, you don’t know about it, which I think is one of the problems. Secondly, yes, another one is that it’s so simplistic. When I started this it did not occur to me that we had a test that was going to be accurate for Parkinson’s disease. Everyone who we see doesn’t have tremor, so why would everyone have a tremor behind their eyes? Well they all do and it’s almost too good to believe. If I wasn’t involved in this, I don’t know, maybe I would be skeptical too. Again it is not something that we logically said, okay there must be a tremor behind the eyes that would be more sensitive than the hand tremor so let’s see if it can accurately predict parkinson’s. As I mentioned, it evolved largely in response to an interest of Dr. Wetzel’s, the biomedical engineer, because he happened to be studying air force pilots. I had at one point, too many projects going on to keep up with them all, and I was able to say, well most of those were not as important as this one is. Why is this more important? Because we were lucky enough to have been studying it.
You do have another project right?
Dr. Baron: In my laboratory at the VA hospital, I am working on understanding the underlying abnormalities in electrical discharge activity that are responsible for the motor problems in Parkinson’s disease and related disorders. I am in particular studying dystonia, which can be a debilitating symptom of Parkinson’s disease, as well as being its own isolated disorder. In the clinic, we are also interested in defining the source for rigidity in Parkinson’s disease. Dr. Paul Wetzel has been working on developing a piece of equipment to study it, which should be very soon available to begin testing subjects. We’re not the first people to study this. I just have a different idea about what is causing rigidity which differs from what is generally believed. Dr. Qutubuddin, my colleague in our VA Parkinson’s Center is looking at the role of various exercise approaches to treating Parkinson’s disease. “Dr. Q” is a a rehab doctor who is pretty unique because he was trained as a fellow in our program, while most other people who get trained in Movement Disorders as fellows are neurologists. He has stayed on with us and is most interested in rehab aspects of Parkinson’s disease. Also, my colleague, Dr. Kap Holloway who heads the DBS surgical program at the VA and at VCU, has been heading up studies to improve surgical approaches for treating Parkinson’s disease and related disorders.
Do you think that this test can revolutionize how we screen for parkinson’s?
Dr. Baron: Definitely. Right now there is no accepted test to diagnose Parkinson’s disease, so the only test you have is you see your doctor, preferably a neurologist or even better a movement disorder specialist who does an examination on you and then decides whether you do or you don’t have Parkinson’s. Even with a specialist maybe ten percent of the time they cannot tell the first time whether you do or do not have Parkinson’s disease. There are many people I’ve seen who have seen other movement disorder specialists who have been misdiagnosed with Parkinson’s disease, or oppositely were told they didn’t have it, but really do. That’s not that uncommon so in that respect, yeah it’s huge that you can use a simple eye test to diagnose Parkinson’s disease. In my clinic, we do this now routinely. I send my patients down the hall for George Gitchel, our graduate student and VA employee, to test them. There’s even a running joke that George makes all the diagnoses and I just prescribe. We also recognize that the eye testing can diagnose not just Parkinson’s disease but many other movement disorders. We submitted a paper that’s being reviewed right now for publication which describes very different and characteristic eye movement findings in people that have another common condition, Essential Tremor. There are many other movement disorders we see in our clinic and each one has its own signature eye movement findings and so we’ve been using this not just for Parkinson’s disease but to help characterize and diagnose many other conditions.
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