Electrical stimulation to the tongue can help treat gait deficit symptoms in MS

As a neuro clinical specialist in physical therapy, I treat many people with multiple sclerosis.

One of the most common neurological effects of the disease is damage to the balance centers in the brain, which impacts patients’ gait.

Of the 1 million people living with MS in the United States, 80% report difficulty walking within 10 to 15 years of disease onset (National MS Society), and of that group 70% cite gait deficit as the most challenging aspect of managing their disease (Larocca).

In most cases, MS attacks the myelin that protects nerve fibers in the cerebellum, which plays a significant role in balance and muscle coordination. Physical therapy has proven to help activate part of the cerebellum, encouraging it to remap new pathways, but in a limited capacity. Most patients show gait improvement initially, but don’t improve beyond a certain point.

In August 2022, a neurologist I work with introduced me to a woman who was interested in trying the Portable Neuromodulation Stimulator (PoNS, Helius Medical Technologies), a new device that can help improve gait by moving beyond the plateau that many people with MS and their physical therapists hit. AS, 36, was diagnosed with MS when she was 15 years old. Since then, she’s been very proactive in researching the latest therapies to address its symptoms, and that’s how she first heard about PoNS.

PoNS works by activating parts of the brain impacting balance and gait via electronic impulses to nerves in the tongue. It’s designed to be used in concert with a 14-week physical therapy protocol, and this combination of prescribed movements and impulses aims to modulate central nervous system activity and trigger neuroplasticity.

The device consists of a small mouthpiece containing 143 electrodes that rests on the anterior dorsal surface of the tongue and a control unit that is worn comfortably around the neck. The mouthpiece gently delivers 2,400 pulses per second across the surface of the tongue, where fibers of the lingual (trigeminal nerve) and chorda tympani (facial nerve) are located. These two nerve branches go to the brainstem and reach beyond the premotor cortex to other parts of the brain involved in movement and coordination. Activating these areas combined with a therapeutic regimen enables the brain to compensate better than physical therapy alone: It offers a stronger neuromodulatory effect, enabling the brain to strengthen its pathways to better control movement associated with walking.

Portability is a key PoNS benefit. There’s quite a bit of lab- and office-based research in stimulation to trigger neuroplasticity. Clinicians commonly use transcranial magnetic stimulation (TMS) to promote neuroplasticity for many afflictions, including MS, with success (Zhou et al.). However, TMS must be performed in a clinical setting. Because PoNS is portable, it allows patients to take ownership of their treatment by taking the device home and performing the exercises and movements on their own between appointments.

That’s a previously underappreciated advantage: For many people with impaired mobility, traveling to clinical appointments — even moving from car to office and back again — can be a significant challenge, particularly without a caregiver’s help. The ability to take such a powerful device home and perform transformative physical therapy independently is a real benefit to these patients.

After meeting AS, I agreed to be her physical therapy partner. I was trained in the therapeutic protocol by Helius Medical Technologies and designed a regimen for AS focused on balance and gait training, upper and lower body strength, and range-of-motion exercises to be performed while she wore the device. The therapy also incorporates mindfulness exercises, which studies show can make a big difference when treating physical ailments (Gilbertson et al., Cherkin et al.). I saw AS every day for the first 2 weeks of the therapy; she worked on her own at home under my supervision for the remaining 12 weeks.

When we first started working together, AS couldn’t stand independently with her feet apart for more than 5 seconds and struggled to take more than a few steps with a rolling walker. Fourteen weeks later, she could stand independently for up to 2 minutes and was able to walk comfortably across a room using her rolling walker. Her 25-foot walk test with a rolling walker went from 59 seconds to 29 seconds. In short, her alignment, speed and endurance have improved, and her enhanced mobility makes a big difference in her day-to-day activities.

Today I have three additional patients undergoing PoNS therapy, and I expect there will be more to come. Currently, the FDA has authorized PoNS for use only in patients with MS, but it has received an FDA Breakthrough Device designation for stroke. It is also approved for use in Canada. I’m excited to see that this technology may have broader applications in the future, and I’m looking forward to helping my patients benefit from what it has to offer.

References:

• Cherkin DC, et al. JAMA. 2016;doi:10.1001/jama.2016.2323.
• Gilbertson RM, et al. Int J MS Care. 2017;doi:10.7224/1537-2073.2015-095.
• How to choose the mobility device that’s right for you. https://www.nationalmssociety.org/nationalmssociety/media/msnationalfiles/brochures/brochure-how-to-choose-the-mobility-device-that-is-right-for-you.pdf. Published 2013. Accessed Oct. 2, 2023.
• Larocca NG. Patient. 2011;doi:10.2165/11591150-000000000-00000.
• Zhou X, et al. Front Immunol. 2022;doi:10.3389/fimmu.2022.902658.

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Naseem Chatiwala, PT, DPT, MS, is the owner/physical therapist at Rehab Health 360 in Acton, Massachusetts.