In a breakthrough research being led by neuroscientist Olaf Blanke and his team at EPFL (École Polytechnique Fédérale de Lausanne) in Switzerland, the scientists show that phantom body pain can be reduced in paraplegics by creating a bodily illusion with the help of virtual reality. The results are published in Neurology.
“We managed to provoke an illusion: the illusion that the subject’s legs were being lightly tapped, when in fact the subject was actually being tapped on the back, above the spinal cord lesion,” explains Blanke, lead author of the study and holder of the Foundation Bertarelli Chair in Cognitive Neuroprosthetics. “When we did this, the subjects also reported that their pain had diminished.”
Paraplegics suffer from no longer feeling their legs again, but the condition is often accompanied by neuropathic pain due to the spinal cord lesion. The patient feels pain originating from the legs, even though nothing else can be felt below the lesion. The sensation of pain is real and yet completely resistant to drug therapy. Now, virtual reality may be the key to providing pain relief for this type of pain, and the solution comes from restoring a sense of touch.
“We tapped the back of the subject near the shoulders and the subject experienced the illusion that the tapping originated from the paralyzed legs,” explains Polona Pozeg, co-author of the study and now neuroscientist at the Lausanne University Hospital (CHUV). “This is because the subject also received visual stimuli of dummy legs being tapped, viewed through the virtual reality headset, so the subject saw them immersively as his or her own legs.”
“It takes about a minutes of simultaneously tapping for the illusion to take place,” says Blanke. “The tapping on the back gets translated onto the legs because the visual stimulus dominates over the tactile one.”
Another one in the VR For Good category, great work!