People with multiple sclerosis often have an increased risk of falling and injuring themselves even when they feel they're able to walk normally. Now a team from the UNC School of Medicine have shown what could be a relatively easy method for the early detection of such problems.

In a new study, researchers used a virtual reality system to trick subjects into thinking they were falling as they walked on a treadmill. The scientists 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 believe that a VR-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.

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. 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. The research team 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.

Researchers employed a VR device that allows the experimental manipulation of visual perception. Their laboratory device is a like a semi-circular theatre screen that subjects watch while walking on a treadmill. The VR 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. The researchers thought 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 indeed a clear difference between the groups in their reactions, but this only became clear when using the VR balance challenge.

Researchers are now adapting the system for use with consumer-grade VR 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 VR system as a tool of physical therapy to help MS patients improve their balance and thus reduce the risk of falls.

The study was published in PLoS One.