Scientists simulate hallucinations in Parkinson's study

Parkinson's patients often experience a condition called presence hallucinations.

"Presence hallucination is this strange sensation or feeling someone which is behind you or close to you when there is actually no one."

The research team at the Ecole Polytechnique Federale de Lausanne - EPFL- says patients experiencing hallucinations tend to overestimate the number of people in a room.

Using a combination of virtual reality and robotics, the team has developed a device that can simulate the hallucinations effect of overcounting people.

PhD student at EPFL's Neuro X Institute, Louis Philippe Albert, explains how the system works: "It's composed of two robots. One which is in front of the participants and one position is at the back of the participants. So the participant is asked to perform a movement with his right arm and the robots at the back is actually reproducing this movement, either in synchrony, so with zero seconds delay between the movement at the front and the movement of the robot at the back. There is a second condition that we call asynchronous condition where we add a delay between the movement of the front and the movement in the back. And when we add this delay, that's when we arrive to induce this presence hallucination in more participants."

The research involved 170 Parkinson’s patients, 69 of whom experienced presence hallucinations.

Researchers say the results indicate patients with presence hallucinations overestimate counts more than those without hallucinations.

There is currently no cure for Parkinson's, which affects more than 10 million people worldwide.

The disease causes progressive brain damage. Common symptoms are tremors, stiffness while dementia is seen in some patients.

Researchers hope the innovative approach could help diagnose and monitor patients at risk of cognitive decline.

Professor Olaf Blanke leads EPFL’s Laboratory of Cognitive Neuroscience, stated: "Our general outlook of this is can we detect dementia with Lewy bodies or hallucinations in Parkinson's disease as a trait 10 years, 20 years before the disease becomes manifest? Because then one could collaborate and empower disease modifying therapies that hope to prolong the onset of the disease by 10, 20, 30 or more years, so you can't cure the disease but you prevent or you hope that the Parkinson disease would only onset at the age of 100 or 110. It's a relative cure in this sense."