Virtual reality helps early detect MS balance problems
An easy and inexpensive method for early detection of balance issues using virtual reality could reduce falls and related injuries in multiple sclerosis (MS) patients, according to a new study published in the journal PLOS One.
Patients with MS often have increased risk of falling and injuring themselves even when they’re able to walk normally. Researchers from University of North Carolina (UNC) Health Care in Chapel Hill, led by Jason Franz, PhD, of the UNC School of Medicine, used a virtual reality system to make subjects think they were falling as they walked on a treadmill. The researchers found clear differences in reactions between people with MS and people of the same age without MS. These differences were not evident between the groups when they walked in a normal way without the "falling" illusion.
The researchers said they believe that a virtual reality-based test like this, after further study and development, could be made portable and used widely in neurology clinics to alert MS patients earlier to their balance impairments, allowing them to adopt measures to reduce their risk of falling.
MS is a brain disease that affects about 400,000 people in the United States and more than 2 million worldwide. It's widely thought to be caused by inappropriate immune cell activity in the brain and features the loss of the insulating layer of myelin protein around nerve fibers, a loss that degrades the fibers' abilities to conduct nerve signals. Signs and symptoms of MS include fatigue, numbness and tingling, cognitive impairments, mood instability, and balance and gait problems.
Balance and gait issues can manifest unexpectedly. People who have MS and show little or no disability may already be at twice the risk of falling, on average, compared to people who don't have MS, the researchers said. Studies also have found that people who have an MS diagnosis fall at least once per year on average. Many of these falls occur during activities such as walking.
Franz and his colleagues sought to develop a test that would reveal balance and gait impairments even in people with MS who may not be aware of these problems or display them during normal walking.
Franz and colleagues employed a virtual reality device that allows the experimental manipulation of visual perception. The laboratory device is a semi-circular theatre screen that subjects watch while walking on a treadmill. The virtual reality scene depicted a hallway, down which the subject seemed to be walking, at the same speed that the subject walked on the treadmill. Sometimes side-to-side wobbles in the scene created the illusion for each subject that he or she was becoming unstable, triggering a corrective reaction that could be measured as a change in gait and foot placement. Franz's hypothesis was that the MS subjects with balance impairments would differ clearly from normal subjects in these corrective reactions.
The scientists tested 14 people with MS and 14 age-matched non-MS participants. They found that there was a clear difference between the groups in their reactions, but this only became clear when using the virtual reality balance challenge.
The next step, researchers said, will be adapting the system for use with consumer-grade virtual reality headsets as a routine diagnostic tool to be used in neurologists' clinics to detect balance impairments that would otherwise go unrecognized. They also hope to develop the virtual reality system as a tool of physical therapy to help MS patients improve their balance and thus reduce the risk of falls.
"Our promising results,” Franz said, “suggest that one can use virtual to detect balance problems that usually go undetected until the individual starts experiencing real falls at home or work.”