A University professor hopes his neuroimaging research on amputee patients examining brain activity associated with their lost limbs will lead to new methods for better rehabilitation.
Scott Frey, director of the Lewis Center for Neuroimaging, began his work at the University shortly after his arrival in 2004.
Frey will use the Lewis Center’s magnetic resonance imaging (MRI) machine to measure subjects’ brain activity as they are asked to perform various exercises intended to create a visual illusion that fools the brain into thinking that the missing appendages are actually present and being used.
To do this, Frey sets a small mirror on the subject’s lap facing the intact hand or arm. As the subject moves his or her arm in front of the mirror, the corresponding reflection creates the illusion of the opposite arm intact and moving in place of the missing appendage.
“We’re able to give the brain feedback – visual feedback as though there are two limbs when there’s only one,” Frey said.
Although the subject may be aware of the situation, the brain can still take the visual stimuli as it would if the limb were real, he said.
“No one’s fooled by this,” Frey said. “No one thinks that suddenly they’re making bimanual movements when they’re making unilateral movements. But, we think that possibly the brain is fooled by this.”
The resulting brain activity could also make it easier for amputee patients to recover and adjust to using prostheses.
“We’re hoping it may be a way to jumpstart rehabilitation,” Frey said.
Frey said the same exercises can also be used for paralysis patients.
The crucial part of Frey’s research is taking it to this next step: using the MRI technology to pinpoint exactly where brain activity occurs during the exercises.
“No one’s ever done the study of how the brain is actually responding to that, and that’s what’s novel about us,” Frey said.
Even without the exercises, Frey said, amputee patients often still feel sensations from their missing limbs.
“Many amputees have a persisting sense of that missing part of a limb remaining,” Frey said. “Whether it’s a leg or hand, there’s often a sense that that limb is still there.”
Often, such sensations come in the form of severe pains called “phantom limb pains,” Frey said.
Frey said the area of the brain that controlled the missing body part does not become dormant, but can actually reorganize itself into being used for other areas of the body following amputation. Sometimes those areas are closest to the missing area.
“We’re really interested in how the brain changes when someone loses a limb,” Frey said. “We know that there’s a competition for real estate that takes place.”
Though amputee subjects won’t be tested until November, Frey said, he is currently trying the method out on healthy, non-amputee University students to locate brain activity corresponding with certain limbs before they are amputated.
The crew at the Lewis Center gave the Emerald a test run of what subjects go through during the MRI evaluation.
Subjects are first required to remove everything from their pockets, especially metal that could be affected by the powerful magnetic field present in the MRI room. Then, they lie down on a platform as a mask-like radio frequency coil is closed inches in front of their face. When they are ready to begin, the platform slides up and backs a subject’s head into a 34-centimeter-wide chamber to be scanned.
As the scanning takes place, the subjects perform the mirror exercises to create the visual stimuli for the brain. Two additional mirrors are also set up in the room that allow subjects to see themselves on a projection screen even while they are in the MRI machine.
“It’s a very simple setup, but there are a lot of profound questions that are presented,” said Jolinda Smith, magnetic resonance physicist in the Lewis Center.
Smith said the crew worked together for a few days trying different arrangements of the mirrors before finding the one they wanted. She also said many of the crew members themselves went into the machine to evaluate the setup.
MRI technologist Scott Watrous, who took part in the setup and works with Frey on the research, said so far the mirror illusion
appears to stimulate the brain as they expected.
“The preliminary stuff looks like it may work,” Watrous said.
Frey was also optimistic about the research. He said eventually the work could lead to the ability to “re-reorganize” the changed brain areas in amputees to their original uses. This brain-area reassignment could make rehabilitation easier for patients learning to use prostheses.
“That would be the biggest goal, and that’s pretty grandiose,” Frey said.
Contact the business, science and technology reporter at [email protected]