They're shadows
I see them as shadows.
They feel like angels protecting me.
The ghosts and guardian angels hidden in the brains of patients with Parkinson's disease
can be revealed with a simple robotic task. EPFL scientists are showing that patients who are more
prone to these presence hallucinations are also more likely to develop severe forms of the disease.
A presence hallucination is this strong sensation to have the feeling of somebody behind and when we turn
around, there is no one. A presence hallucination is a very frequent symptom in Parkinson's
disease, happening in 40 to 60, 70 percent of patients.
We have no true understanding of
how hallucinations are generated by the brain, so what our procedure does is that we can do this in
the lab, so we don't have to wait for the state to appear spontaneously. We can induce it in the lab
across several conditions and in a controlled way. We refer to it as the "hallucination stress test".
The system is actually quite simple. We have two robots, one robot is in front of the subject and
will measure the movement and the second robot will feed back signals to the individual that
we're testing, Parkinson's patients or healthy subjects. And then, when we induce a mismatch, so
if the front robot is doing something else then the back robot, this is the condition where the
presence hallucination occurs. By having a delay between the front movement and the touch on the back
we trick the brain into perceiving this presence hallucination. This we believe is generated due to the
fact that the brain makes a prediction of what will happen. Because of the delay, this prediction is
falsified, therefore, it thinks that there is somebody behind them during the robotic task.
It happens in a safe environment and the patient can also realize that it's not
a strange thing that happens, it's something that really is based on very specific brain mechanism.
Maurizio De Levrano was diagnosed with Parkinson's in 2015.
The "robotic hallucination stress test" helped him to understand that
he had already experienced presence hallucinations due to the illness.
I remember the first time, I was peeling an apple.
All of a sudden, while peeling the apple, I felt shivers down my back.
The first time, I didn't move, then a second time, and after a few shivers, I had to turn around.
This presence, I associated it with the presence of my mother,
my mother who died in 2010, and I said to myself, she's come here to tell me something.
Joseph frey was diagnosed with Parkinson's disease
in 2009. His first hallucinations were of his shadows that he calls his guardian angels.
I started to feel, on my right side, a presence,
and this presence, it wasn't negative, it wasn't violent. It was a very gentle presence.
The scientists focused on revealing presence hallucinations among 26 patients with Parkinson's.
Both De Levrano and Rey were among the more sensitive to the robotic task. They've also
reported more severe hallucinations, outside of the lab. This time their hallucinations were visual.
I'm having a drink, or taking a pill, and I see falling on each side something like threads with spiders.
I force myself not to look, but eventually, my eyes go to look and there's nothing there.
There was once a violent moment.
I was sitting there, watching TV.
I felt a presence to my left.
I turned, I looked and I saw myself.
It was violent. I was scared.
We can predict and define a subgroup of patients suffering from Parkinson's disease
who are extremely sensitive to our "hallucination stress test" and this "hallucination stress test"
is linked with negative consequences that these individuals may develop. So we can predict
whether you're part of that group or of another group of Parkinson patients.
We want to go more deeply into the neuroscience of this particular hallucination as well as related
hallucinations. We have to further improve our robotic design and and methodology
so that it's robust and can be tested in in clinical trials. What we want to do is
try to see whether even 10 years before you develop Parkinson's disease, and there are
certain ways of detecting those individuals who may be at risk developing Parkinson's disease,
whether among these individuals, we can also have a similar discrimination. So this could
lead to findings that before you have any motor symptoms of Parkinson's disease, we can already
tell you, based on the test, whether you will have more severe forms of Parkinson's or not.
I see the light, the end of the tunnel is over there, and I'm running torwards it.
But the tunnel is a dynamic one, it's not static.Why? Because it keeps on getting longer.
I see the light but the tunnel keeps on getting longer. It's like a telescopic tube,
the more we run, the longer the telescope gets.
I'm even more passionate about participating in these tests, because I'm curious to know what like has in store for me.
Fruit speak to me of clear waters that soak the Earth
I can carry a thousand words on my stooped back
But prisoner of my dreams, they die
So gently, I sew them behind me
And free, they fly away in the wind.