Difficulty walking, called impaired gait, is one of the most common mobility-related problems resulting from nervous system damage in multiple sclerosis (MS). Balance and gait problems are estimated to affect 50%–80% of people with MS.
The Portable Neuromodulation Stimulator, or PoNS, is an approved noninvasive medical device that is used in combination with physical rehabilitation to reduce MS-associated walking problems.
The device is marketed by the U.S.-based company Helius Medical Technologies.
Voluntary movement, such as walking, depends on fast and effective communication between the brain and the muscles involved in that movement. This communication is often affected by neurological conditions such as MS.
In MS, walking difficulties arise from a number of disease symptoms, including spasticity — stiff or tight muscles — balance problems, muscle weakness, fatigue, and sensory deficits such as numbness in the feet.
The PoNS device consists of a mouthpiece containing more than 100 gold-plated electrodes and a controller that is worn around the neck. The two pieces are connected via a cord.
The mouthpiece is placed on the tongue and delivers mild electrical signals that are transmitted to the brain through two major cranial nerves in the tongue: the trigeminal and facial nerves.
The trigeminal nerve is responsible for biting, chewing, and swallowing, as well as face sensations. The facial nerves, meanwhile, control most of the muscles involved in facial expression. These nerves directly connect with the brainstem — a control center for functions such as sensory perception and movement — which, in turn, communicates with other parts of the brain.
The electrical signals delivered through the PoNS device are thought to create a natural flow of stimuli from the tongue to the brain. This promotes neuroplasticity, or the brain’s ability to adapt or rewire itself in response to new experiences.
When combined with targeted physical training, the device is expected to promote the development and strengthening of neuronal circuits related to a given task. The goal is to retrain mind-body connections and boost the benefits of rehabilitation in MS patients.
According to the device’s developer, the electrical impulses produced by PoNS to the tongue are not harmful. Patients may perceive them as a “buzzing” or “champagne bubble” sensation.
The U.S. Food and Drug Administration approved the PoNS device in 2021 as a short-term treatment for walking problems in MS patients with mild to moderate symptoms. The device is authorized for use in combination with supervised therapeutic exercise programs, for people ages 22 and older.
PoNS also is approved — as an add-on to a therapeutic exercise program — in Canada and Australia for the short-term treatment of walking problems in MS patients. In Canada, treatment with the device lasts 14 weeks and is available to patients ages 18 to 65.
In the U.S., the device is not recommended for pregnant women and individuals younger than 22, as it has not been tested in these patient groups.
It also should not be used by people with:
The PoNS device is used during 20-minute sessions of physical therapy over a short-term period. Stimulation intensity is adjusted individually to each patient, and treatment is conducted by rehabilitation therapists who have completed specialized PoNS training.
A combination of PoNS and targeted physical therapy was assessed in two pilot clinical trials. These studies investigated the device’s impact on walking ability in a combined total of 34 MS patients.
The first trial (NCT04498039), sponsored by the University of Wisconsin, involved 20 adults with MS-related gait problems who were still able to walk 20 minutes on a treadmill without rest.
Participants were randomly assigned to use either PoNS or a sham device — providing very low, nonperceivable stimulation — during training sessions over a 14-week intense exercise program.
The exercise program was similar for both groups, involving training sessions for five consecutive days each week. Each training day consisted of two similar appointments — a morning training session and one in the afternoon. Patients first performed some movement exercises without the device. Then, the participants wore the device for 20 minutes of gait training, 20 minutes of balance training, and 20 minutes of relaxation exercises.
The overall program comprised two weeks of twice-daily sessions in the laboratory, followed by 12 weeks of the same daily routine at home.
Trial data showed patients using the PoNS device experienced a statistically and clinically significant improvement in walking skills after six weeks, which was sustained through 14 weeks. No such gains were observed in the sham group. Walking skills were assessed with the Dynamic Gait Index (DGI), which tests a person’s ability to maintain walking balance while doing different tasks.
The second trial (NCT04496531), sponsored by Helius and conducted with McGill University, in Canada, had a similar design. A total of 14 adults with MS used either PoNS or a sham device while undergoing intensive physical and cognitive training for 14 weeks.
Like the U.S.-based trial, this program was conducted in the lab for the first two weeks and at home thereafter. It also included twice-daily 90-minute sessions of warm-up, balance, gait, and motor control exercises.
But patients in this trial also had breathing and awareness training during sessions, and an extra session of breathing and awareness before bedtime. Cognitive and working memory training also was performed four times a week for 10 weeks.
At the end of the program, five of the seven participants assigned to the sham group chose to subsequently complete the training program with PoNS (rollover group).
Results from the study demonstrated that the PoNS group, but not the sham group, showed statistically significant improvements in balance after 14 weeks. Patients in the rollover group also exhibited steady balance gains with the PoNS-training combined intervention.
Moreover, brain imaging during walking and cognitive tasks showed that brain regions linked to such functions were significantly activated only among patients who received the electrical stimulation. The sham group showed a different pattern of motor region activation and no greater activation of cognitive regions.
The use of PoNS also was associated with a trend toward greater improvement in DGI scores and in cognitive function relative to the sham device. However, these differences did not reach statistical significance.
The device was generally well-tolerated in both trials, with no reports of serious adverse events.
Clinical trials in MS patients have not reported side effects associated with the PoNS device. Some side effects were reported, however, in clinical trials involving patients with chronic balance issues due to traumatic brain injury for whom the device also is approved in Canada.
According to clinical data from that multicenter trial, the most common side effects of PoNS were:
Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
The U.S. Food and Drug Administration approved the PoNS device in March 2021 as a short-term treatment for walking problems due to mild to moderate symptoms of multiple sclerosis. The approval is for use in combination with supervised therapeutic exercise programs in adults ages 22 and older.
Clinical trials investigating the PoNS device have not accepted people who were pregnant, so it is unclear whether the therapy is safe in such conditions.
No study has assessed the effects of alcohol on PoNS use, or vice versa, but alcohol can interfere with brain activity, some medications, and disease symptoms. Therefore, patients should discuss this topic with their healthcare provider.
Some patients in clinical trials have seen improvements in walking ability within the first two months of use. But the intensity of PoNS electrical stimulation can vary from person to person, and the targeted exercises are tailored to a person’s individual needs. Thus, there can be a lot of variability in the time it takes for PoNS and the exercise intervention to produce evident benefits. The earliest time point reported for improvements in walking skills in MS clinical trials was six weeks.
Hair loss and weight gain were not reported as side effects of PoNS in clinical trials. Patients should talk with their healthcare team if such events occur.
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