Robotic Exoskeleton Intervention Improves Motor, Cognitive Function

Four weeks of robotic exoskeleton-assisted exercise rehabilitation, called REAER, worked better than conventional gait training in improving mobility and cognitive function in multiple sclerosis (MS) patients with substantial walking difficulties, according to a small trial.

A robotic exoskeleton consists of an externally worn device that encases a user’s hips, back, and legs during rehab, providing greater physical performance.

These findings further emphasize the potential benefits of exercise in both mobility and cognitive function, according to researchers, who noted that gains seen in the trial were associated with improved connectivity between brain regions involved in cognition and motor function.

While larger studies are needed to confirm these results, the investigators said REAER shows tremendous promise for treating MS — and improving patients’ lives.

“Four weeks is relatively short for an exercise training study,” Brian M. Sandroff, PhD, one of the study’s authors and a senior research scientist at the Kessler Foundation, a major nonprofit organization in the field of disability, said in a press release.

“Seeing improvements within this timeframe shows the potential for exercise to change how we treat MS,” added Sandroff, director of Kessler’s exercise neurorehabilitation research laboratory.

“Exercise is really powerful behavior that involves many brain regions and networks that can improve over time and result in improved function,” he said.

The study, “A pilot randomized controlled trial of robotic exoskeleton-assisted exercise rehabilitation in multiple sclerosis,” was published in the journal Multiple Sclerosis and Related Disorders.

Mobility problems and cognitive impairment are common MS symptoms that tend to occur together. Exercise rehabilitation, particularly programs that involve actual walking, has been shown to improve both mobility and cognitive function in MS patients.

However, severe disability in terms of walking “oftentimes precludes participation in highly-intensive and repetitive [exercise rehabilitation] that is necessary for eliciting mobility and cognitive adaptations,” the researchers wrote. Simply put, patients with more severe walking problems often are unable to participate in the intensive rehab needed for best results.

Given its ability to boost a user’s physical performance and to correct altered walking patterns (impaired gait), as well as its associated close engagement with a physical therapist, REAER may revolutionize exercise rehabilitation for MS patients, the researchers said.

Once considered science fiction material, robotic exoskeletons are already in use for people with reduced mobility due to health conditions, such as spinal cord injury and stroke.

However, until now, no appropriately controlled trial had evaluated REAER’s benefits in people with substantial MS-related neurological disability.

This pilot trial, which was partly funded by the National MS Society, involved 10 highly educated adults (mean age 49.9) with relapsing-remitting MS and significant disability. The participants were randomly assigned to undergo either a 30-45 minute session of REAER (six patients) or conventional gait training (four patients), twice a week for four weeks (about one month).

REAER involved progressive walking training over-ground using Ekso Bionics’s Ekso-GT, the first robotic exoskeleton cleared by the U.S. Food and Drug Administration for use in people with spinal cord injury or stroke.

Ekso-GT can provide adaptive amounts of power to either side of an individual’s body, challenging the patient as he or she progresses through rehabilitation. It has been shown to mobilize patients earlier, more frequently, and with a greater number of high-intensity steps.

In the group of patients receiving REAER intervention, the maximum allowable degree of robotic assistance was progressively reduced across the sessions.

The researchers assessed patients’ functional mobility, walking endurance, cognitive processing speed, and brain connectivity. Cognitive processing speed is the amount of time it takes a person to take in information, process it, and then react to solve a problem or complete a task.

Brain connectivity was assessed specifically between the thalamus and the ventromedial prefrontal cortex, two brain regions involved in cognitive function and cognitive control of motor activities.

Every participant attended all eight sessions over the four-week period.

The results showed that patients undergoing REAER had large improvements in functional mobility, cognitive processing speed, and brain connectivity after the four-week intervention. Indeed, as an example, these patients took about 59% more steps during the last session compared with the first.

In the conventional training group, meanwhile, the patients’ outcomes remained stable or worsened after the intervention.

Additional analyses found that increased connectivity between the thalamus and the ventromedial prefrontal cortex was moderately associated with improved functional mobility, walking endurance, and cognitive processing speed.

These findings suggest that REAER-related improvements in brain connectivity “might explain downstream adaptations” in motor and cognitive function, the researchers wrote.

The progressive reduction in robotic assistance over the four-week intervention, the team hypothesized, may have promoted brain communication adaptations to keep up with the increasing demands of REAER, leading to improved brain connectivity and functional outcomes.

“This is particularly exciting considering that REAER might represent an innovative approach for rehabilitating the highly prevalent and burdensome consequences of co-occurring mobility and cognitive disability in MS that may even be superior to the current standard-of-care,” the researchers added.

While some of the study’s findings failed to reach statistical significance, this may be due to the small number of participants, which also may limit the generalizability of the results among the general MS population, the team noted.

Nonetheless, the findings are “particularly exciting” because of REAER’s potential “for improving the lives of people with co-occurring mobility and cognitive disability” — the group that likely has “the greatest potential to benefit from this new technology,” said Ghaith J. Androwis, PhD, the study’s lead author and also a research scientist at the Kessler center.

Androwis said the team plans to design a larger trial to further study the effects of robotic exoskeleton-assisted exercise rehabilitation.

“We’re optimistic that this approach may be superior to the current standard of care,” he said.