Playing virtual reality games may reduce phantom limb pain and improve quality of life, say researchers from Chalmers University of Technology in a clinical study published in The Lancet.
Dubbed “phantom motor execution,” the new treatment method consists of using muscle signals from an amputated limb to control virtual environments. Electric signals in the muscles are picked up by electrodes on the skin. Artificial intelligence algorithms translate the signals into movements of a virtual arm in real-time. The research participants see themselves on a screen with the virtual arm in the place of the missing arm, and they can control it as they would control their biological arm.
“We selected the most difficult cases from several clinics,” said lead author Max Ortiz Catalan, Assistant Professor, Chalmers University of Technology in Sweden. “We wanted to focus on patients with chronic phantom limb pain who had not responded to any treatments. Four of the patients were constantly medicated, and the others were not receiving any treatment at all because nothing they tried worked. They had been experiencing phantom limb pain for an average of 10 years.”
The participants were treated with the new method for a total of 12 sessions. At the last session the intensity, frequency, and quality of pain had decreased by approximately 50%. The problems pain causes in sleep and daily activities were also reduced by half. In addition, two of the four patients who were taking pain medication were able to reduce their doses by 81% and 33%, respectively.
“The results are very encouraging, especially considering that these patients had tried up to four different treatment methods in the past with no satisfactory results,” Ortiz Catalan says. “In our study, we also saw that the pain continuously decreased all the way through to the last treatment. The fact that the pain reduction did not plateau suggests that further improvement could be achieved with more sessions.”
The perceived phantom limb is brought to life by a virtual representation that the patient can see and control. This allows the patient to reactivate areas of the brain that were used to move the limb before it was amputated, which might be the reason that the phantom limb pain decreased. No other existing treatment for phantom limb pain generates such a reactivation of these areas of the brain with certainty. The research led by Ortiz Catalan not only creates new opportunities for clinical treatment, but it also contributes to our understanding of what happens in the brain when phantom pain occurs.