The Final Word: UTD’s Balakrishnan Prabhakaran on Virtual Reality Technology for Phantom Limb Pain

UTD computer scientists developed a phantom pain management system in collaboration with researchers from the Veterans Affairs North Texas Health Care System. [Photo: UTD]

dr. Balakrishnan Prabhakaran
computer teacher
UT Dallas
.…about the co-development of the Mr. MAPP VR system for amputees with phantom limb syndrome.

Dean PetersonA US Navy veteran who lost his left leg 16 years ago after a hunting accident slept better for the first time in years when he took part in a recent pilot test of Mr. FILE. The “mixed reality” system combines virtual reality and computer vision technologies and was co-developed by dr. Prabhakaran.

The system uses a laptop, camera and VR headset to create a virtual 3D model of the user’s missing or paralyzed limb. Wearing the VR headset, Peterson played a series of games where the virtual model of his missing leg did things like stomp on the ground or burst a bubble.

“The idea is to trick your brain into seeing a leg and a foot,” Peterson said in a statement. “After three weeks in the study, I realized that the pain didn’t bother me so much at night. It was easier to fall asleep. I was impressed.

Peterson was just one of twelve veterans who participated in a pilot home trial of Mr. MAPP through the Dallas VA Medical Center. Mr. MAPP—short for Mixed reality system for Managing Phantom Pain—was created after years of research led by dr. Prabhakaran in collaboration with researchers from North Texas Veterans Health Care System.

Mr. MAPP uses RGB-D cameras as Microsoft Kinect to produce a real-time 3D model of the patient. An illusion of their virtual limb is created by reflecting their preserved limb in captured data, using computer vision and graphics.

Prabhakaran and his fellow researchers see Mr. MAPP as a potential alternative to using opioids and believe the technology can also be used for other conditions that cause pain.

A high-tech VR update of a classic therapy

Mixed signals to the brain, even many years after an amputation, are thought to be the cause of phantom limb pain. The Mr. MAPP system is designed to help the brain resolve signals. It is an update of the classic “mirror box therapy” treatment, which uses a box and a mirror to give the patient the illusion of their missing limb. But box and mirror therapy isn’t ideal, says Prabhakaran, and is usually only offered in health care settings.

Using virtual reality and augmented reality technology, which superimposes real-world objects into virtual environments, Mr. MAPP enhances treatment, while allowing patients to use Mr. MAPP themselves directly at their home.

Peterson had unsuccessfully tried mirror box therapy in the past, which is why he’s excited about Mr. MAPP’s potential.

“It was a pretty cool feeling. It felt like I had two feet, and it was cool enough that I wanted to stick with it,” Peterson said.

Lead author Prabhakaran and co-authors of the study described Mr. MAPP in an article published online Oct. 22 in Pilot and Feasibility Studies.

Co-authors of the UT Dallas study include Kanchan Bahirat, Ph.D.who worked on the project as a PhD student and now works at Lazy robotics, and Yu Yen Chung, PhD student in computer science. Other contributors include corresponding author Dr. Thiru Annaswamyformerly with UT Southwestern Medical Center and the Dallas Virginia and recently appointed Chair of Physical Medicine and Rehabilitation at Penn State Health Milton S. Hershey Medical Center; dr. Gargi Raval, assistant professor of physical medicine and rehabilitation at UT Southwestern; and Tri Phama medical student from UT Southwest.

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