Judy Lee Baldwin-Mohn hasn’t played soccer since high school. Her leg was amputated below the knee after an infection that stemmed from a bug bite found its way into her bone. Ever since the operation, she has suffered from phantom limb pain, a condition in which amputees feel aches in their former body parts.
“It’s like electrical impulses that can shoot all the way up to my thigh. It throbs, and it burns, and it stings,” she said. Sometimes, she feels a charlie horse in the arch of her former foot; at other times, it’s a terrible itch in her big or little toe.
But now at age 68, the U.S. Air Force veteran is able to get back on the field — virtually — thanks to a new kind of therapy at the VA Puget Sound Health Care System.
When Baldwin-Mohn straps on a virtual reality headset and becomes a soccer player, something remarkable happens. Her phantom limb pain goes away, an effect that she says lasts well after she’s done playing. “My pain has been less frequent and the depth of the pain has decreased tremendously,” she said.
Phantom limb pain is tough to treat for reasons that may be obvious.
“Imagine you don’t have a foot but you feel as if you’ve stepped on a thumbtack. How do you fix that pain? There is no thumbtack. There is no foot,” said David Boe, a researcher who is working with Baldwin-Mohn as part of the virtual reality project.
Boe is testing out an early-stage effort for “limb simulator therapy” within the Center for Limb Loss and Mobility (CLiMB), a research group within the VA Puget Sound. The organization, which is home to the fifth-largest research program in the VA system, recently opened $121.6 million building in Seattle.
People suffering from phantom limb pain are often given opioids and anticonvulsants to manage the pain. Another option is a therapy in which mirrors are used to visually replace a patient’s missing limb with their intact one. For some patients, seeing the “replaced” limb can reduce the pain.
Boe became interested in virtual reality after realizing that these treatments weren’t solving the problem of phantom limb pain. He thought that if he could give patients back their foot with virtual reality, they could take the metaphorical thumbtack out themselves.
When a person loses a limb, the mind has to reconfigure how it senses the body in space. For unknown reasons, the perception of pain can get mixed up in that new model, resulting in phantom pain, Boe said.
“We think that we can guide people back to that normal model of their limb and thus no phantom limb pain,” said Boe, who plans to secure more funding from within the organization and eventually pursue a clinical study.
Nearly 2 million Americans have lost a limb, and around 80 percent of amputees report suffering from phantom limb pain. The problem is only expected to grow — most amputations are the result of diabetes, a disease that affects nearly one in 10 Americans.
There’s a precedent for what Boe is trying to do. A VR experience called SnowWorld has been shown to help manage pain in the case of burn victims. The virtual world acts as a temporary distraction for patients who are having their wounds treated, said Dr. Hunter Hoffman, a director of virtual reality research at the University of Washington who co-created SnowWorld.
Hoffman sees huge potential for VR to help phantom limb patients. “It’s one of the few types of pain where you can have a dramatic improvement in the pain itself,” he said.
But unlike burn patients, people suffering from phantom limb pain don’t need a distraction. They need help rewiring the way their brain perceives pain.
When Baldwin-Mohn puts on her VR goggles, she can look down and see a pair of legs. Aside from her avatar, there’s a ball, a field and a target — and not much else.
“As a game, it’s fairly primitive,” said Boe, who created the game himself after teaching himself the basics of VR design. Still, Boe said that his patients often get addicted to the game and don’t want to stop playing — just like teenagers.
“I’ll ask them to take a break. And it’s like they’re not even hearing me,” he said. “I actually have to go into the editor and delete the balls out of the scene for them to stop kicking it.”
Baldwin-Mohn is one of those patients. She even dreams about the game sometimes. If she can’t sleep because of the pain, she’ll visualize the game as a kind of meditation.
As virtual reality has become more mainstream, Boe said that people have become less skeptical of his plan to treat phantom limb pain. “Recently, we have gotten almost overwhelming interest from the local therapist community about the potential for this,” he said. The VA plans to expand the limb simulator therapy to more clinics.
Eventually, Boe wants virtual reality to be the “go-to” therapy before prescribing opioids and anticonvulsants.
Baldwin-Mohn hopes the therapy can benefit other veterans who also suffer from phantom limb pain. “To look down and see a leg and foot again was the most awesome feeling,” she said. “This program will benefit so many veterans.”