Virtual Reality Test Can Detect Subtle Balance Issues in MS Patients

To gauge the risk of falling, the researchers utilized a virtual reality (VR) device that simulated the act of walking down a hallway while participants walked on a treadmill. The researchers would then introduce the illusion of side-to-side “wobbles” in the simulation to make participants feel that they were falling, and measured how they responded to the illusion.

The theory behind the use of VR is that MS patients may be compensating for walking deficiencies by relying on their visual abilities. They may have the impression that their walking is normal, but these patients are still at risk for falls.

“When we walk around, our brains use a variety of sensory feedback channels, including force sensors in our feet, to guide our movements and make corrections from one step to the next,” Jason Franz, PhD, the study’s senior investigator, said in a press release.

“But in people with MS, those force sensors can become less reliable, so people need to rely more on other channels, especially vision,” Franz added.

To measure the participants’ responses, the researchers used 3D motion capture cameras to look for any fluctuations in each step (gait variability), differences in overall motion (kinematics), and balance (margin of stability).

Results showed that the measurements taken for standard walking — before the wobbles were introduced — were similar between MS patients and healthy volunteers.

“During normal walking without VR — even with our sophisticated lab equipment including a battery of 3D motion capture cameras — we could not effectively distinguish people with MS from the healthy, age-matched individuals,” said Franz.

However, once participants experienced the falling simulation, there was a clear and statistically significant difference in how MS patients responded — they exhibited a higher variability in step width, position, and stability.

Furthermore, MS patients performed worse than healthy controls on the standing sensory organization test, which assesses a person’s ability to use visual cues and others to maintain postural stability.

“So this perturbed-walking approach could have a lot of important clinical and translational applications,” Franz said.

Based on the results, the team said that its VR simulation technology “revealed differences in walking balance in [MS patients] that went undetected during normal, unperturbed walking. Targeting this difference may be a promising approach to more effectively detect preclinical walking balance deficits” in MS.

Encouraged by the findings, the researchers are now developing the technology to be used as a general diagnostic tool to identify balance impairments. They believe that such a test, potentially portable and inexpensive, could reduce the number of falls and associated injuries among MS patients.

“Our promising results suggest that one can use VR to detect balance problems that usually go undetected until the individual starts experiencing real falls at home or work,” Franz said.