Real Results
Monday February 15, 2010
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CAREN system at the Military Rehabilitation Center in Doorn, the Netherlands
(Photo courtesy of Motek Medical)
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The CAREN at Walter Reed is one of only three devices of its kind in the U.S. Others are located at the Naval Health Research Center in San Diego and Brooke Army Medical Center in San Antonio, home of the first CAREN in the U.S. and the only one with a 21-foot domed screen.
Patients who use the device are secured by a harness as they stand on a treadmill embedded in a platform that can move along three different axes and rotate. The motion-capture system tracks the patient’s movements via reflective markers on the body. Meanwhile, patients are immersed in a virtual world on the surround screen.
“The CAREN has inclines and declines that are superior to a ramp in a traditional setting,” says Sarah Kruger, BS, MS, the biomedical engineer who operates the CAREN at Walter Reed. “We can simulate things like an uneven terrain, and the harness makes it a safe place for patients to challenge themselves.”
How it Works
The CAREN can be used to help patients who suffer from a variety of conditions, including amputations, vestibular deficits, traumatic brain injuries, visual impairment, back pain and post-traumatic stress disorder.
The device at Walter Reed arrived in late 2007 with three virtual environments. Kruger worked with PTs, OTs and patients to develop 70 new virtual environments to meet the needs of patients with varying conditions and skill levels. The virtual experience can range from skiing to shark hunting to walking on a busy city street.
For example, a patient with a TBI or visual impairment may need to practice multitasking. In this case, the patient can use a program that includes a mathematics problem on a screen as he or she is walking on a virtual city street. As the patient becomes more adept, Kruger can adjust the level of difficulty by adding more distractions, such as pedestrians walking toward the patient, people talking or a car backfiring.
During each session, a PT or OT assesses the patient’s quality of movement and offers suggestions. For example, he or she may notice that a patient is leaning or hiking the hip, or taking a longer step on one side.
At Walter Reed, if the patient’s PT or OT is not able to attend the session, then Barri Schnall, MPT, manager of the Center for Performance and Clinical Research, will attend. She will manually assist patients who have limited mobility or lack of confidence as they progress through a virtual exercise.
“One of the advantages of the CAREN is that when patients are immersed in a virtual environment, they can forget that they are doing therapy,” Schnall says.
The CAREN also allows patients to push themselves beyond what they may feel comfortable with in the real world because they have the safety of a harness. “We provide a safe means for patients to challenge themselves,” says Benjamin Darter, PT, PhD, who works in the Center for the Intrepid at Brooke Army Medical Center.
One patient at Walter Reed, for example, was suffering from vestibular dysfunction and had to sidestep up her own steep driveway because she was afraid of falling if she walked straight up it. Kruger started the platform flat with the screen showing a virtual road, and eventually increased it to 14 degrees over the course of several sessions.
“She came in the day after she had made it up her driveway walking straight, and she looked like she had won the lottery,” Kruger says.
Another advantage that the CAREN has over traditional PT is that it provides quantitative feedback, Darter says. The motion capture system allows him to project a virtual image of the patient’s movement pattern onto the screen so he can show the patient exactly how his or her movement is compromised.
“People have come out of there with a new appreciation for what they look like,” he says. “People become much more aware about the way they are walking, and the ability to present it on the screen really helps it sink in for patients.”
The CAREN also provides quantitative results in terms of times and scores, like video games, and working to improve these numbers motivates many patients, Kruger says. In the case of the bilateral amputation patient in his 20s who had suffered a blast injury, he started with a time of five minutes, 22 seconds on the buoy course, which was an average time compared to other patients. After several weeks of practicing, he was able to complete it in 2:16 with waves that were 2 feet tall — the fastest time ever for the course. As patients master the exercises in the virtual world, this translates to more confidence performing activities in the real world, Schnall says.
Future Projections
In addition to helping patients in a clinical setting, the CAREN also is being used for research purposes. “A TBI patient may look great, but if we put them in a cognitive challenge or on a moving platform that elicits a response that identifies a problem, then we can use that to develop better assessment tools,” Darter says.
So far there are 14 CAREN systems operating worldwide, and 11 more are ordered to be installed worldwide in 2010, says Elisabeth Wessels of Motek Medical, maker of the CAREN. Walter Reed will be moving to a site in Bethesda, Md., where the facility will upgrade to a CAREN that has a 180-degree surround screen rather than the current 120-degree screen. Although Darter and Kruger agree that the CAREN requires money and space to install — ranging from $350,000 to $1 million to buy it and a two-story room — the possibilities it allows rehab patients are innumerable. •
Heather Stringer is a contributing writer for Today in PT.
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