Improving walking in people with MS using neuromodulation and physical therapy
For people with multiple sclerosis (MS), maintaining the ability to walk safely and efficiently is an important factor in their independence and quality of life. But as the disease progresses, patients are often faced with gait abnormalities, including slower speed, strength asymmetries, a shortened stride, balance issues, sensory impairment, fatigue, spasticity and reduced coordination and cognitive function.
Clinicians have various rehabilitation strategies to address these issues. But according to Deborah Backus, PhD, PT, from Shepherd Center in Atlanta, patients often plateau.
“They reach a point which they can no longer improve,” she says. “They can no longer access the systems needed to be able to improve their walking function, their mobility, and their safety as walking. They oftentimes have persistent gait and balance deficits, regardless of the fact that they may improve a little bit. And for those who do improve, they often will lose those improvements if they stop the intervention.”
Because of this, Backus says clinicians and researchers have been looking for ways to turn on the nervous system and help it become more responsive. She presented results from a recent multi-site pragmatic trial involving one of these methods during the second day of the 39th Consortium of MS Centers Annual Meeting, which runs through May 31 at the Phoenix Convention Center in Phoenix.
The study utilized a type of noninvasive neural stimulation called translingual neuromodulation (TLNS) that stimulates cranial nerves. The stimulation is provided by a device called a portable neuromodulation stimulator (PoNS), which is an orally applied therapy delivered by neurostimulation through a mouthpiece connected to a portable controller. It delivers mild stimulation to the tongue’s surface, and it’s a Food and Drug Administration-approved for treatment of people with MS and can be obtained with a prescription.
The stimulation intensity of the electrode array on the tongue matches the sensory sensitivity map of the tongue. When turned on, the mouthpiece stimulates neurons in the brainstem and the cranial nerves, causing neuromodulation throughout the brain.
“The idea is that training with this portable neuromodulation stimulator, or PoNS, can help elicit neuroplastic changes in the brain and, in fact, can be combined with activities such as gait and balance exercises. When TLNS is applied without the activity, we already see activation of circuitry and pathways in the brain that are related to movement and coordination, promoting the neuroplasticity through neuromodulation processes.”
For the PoNS Therapeutic Experience Program, or PoNSTEP, the six participating sites, enrolled 41 adults with MS in a 14-week therapy program that combined PoNS with physical therapy. There were three phases. Phase one was daily treatment for two weeks in the clinic with PoNS combined with physical therapy. In phase two, patients continued to perform the exercises daily for 12 weeks at home. The third phase was a six-month follow-up and reevaluation.
Participants performed warm-up exercises and movement control training without PoNS, then did some form of gait training, balance training or breathing and awareness training with PoNS. The goal was 100-120 minutes per day for six days per week performing this routine. The controller logged each time it was used and had an accelerometer to show participants’ activity intensity. Backus says 38 of the 41 participants completed the 14-week treatment intervention.
Researchers found the PoNS therapy plus physical therapy made meaningful improvement in phase one and even further improvement in phase two on the Dynamic Gait Index (DGI), which consists of eight functional gait tests. A score of less than 19 on the DGI has been shown to be correlated with an increased risk of falls. In addition, Backus says participants who had greater adherence had significantly more improvement on the DGI. At a six-month follow-up, there was only a slight decline in DGI scores, even after participants discontinued the intervention.
“Adherence to this therapy, the PoNS plus physical therapy, was associated with gait improvement in people with MS,” Backus says. “And we saw that greater adherence, there were greater outcomes, suggesting a dose response. This data supports the effectiveness for sustained improvements at six months and of course warrants further investigation. But this suggests that there’s some underlying neuroplasticity that leads to enduring gait improvements in people with MS.”
