Scientists at École Polytechnique Fédérale de Lausanne, Switzerland have demonstrated that phantom body pain in paraplegic patients could be reduced by creating a bodily illusion using virtual reality (VR), according to a study published Neurology.
Even without their legs, many paraplegics suffer from phantom neuropathic pain due to spinal cord lesions. In this study, led by neuroscientist Olaf Blanke, researchers evaluated the effect of VR in helping create an illusion and reducing phantom pain.
The study used a pair of fake legs, a camera, VR googles and rods to create the illusion. The legs were filmed in real-time and displayed in VR googles worn by a patient so he would view the legs from above. Researchers then tapped the patient's back with one rod while also tapping the dummy legs with another.
"We tapped the back of the subject near the shoulders and the subject experienced the illusion that the tapping originated from the paralyzed legs," explained Polona Poeg, co-author of the study and a 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 immersivily as his or her own legs."
"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," said Blanke. "When we did this, the subjects also reported that their pain had diminished."