Interview: Helius CMO on game-changing tongue stimulation tech

A first-of-its-kind technology is boosting the benefit of physical therapy for MS patients through electrical pulses that aim to ‘rewire’ the brain and activate neural pathways.

Physical therapy is an essential aspect of treating MS, but it has its limitations. In most cases, MS affects the cerebellum, also known as the brain stem.

Physical therapy is able to non-selectively activate the cerebellum, however, most patients find they will reach a certain degree of improvement in their gait that they struggle to progress past.

But now, a first-of-its-kind medical device, developed by the Nasdaq-listed neurotech company Helius Medical Technologies, is helping MS patients drastically improve their ability to walk by using electrical stimulation to activate brain pathways and amplify the power of physical therapy.

The device is known as a Portable Neuromodulation Stimulator (PoNS).

Helius discovered through brain imaging studies that in patients with MS and gait deficit, physical therapy can only activate the premotor cortex.

However, the control of movement is a function of other additional areas of the brain, such as the supplemental motor cortex, the motor cortex and the frontal and prefrontal cortex.

Dr Antonella Favit-Van Pelt, chief medical officer at Helius (pictured above, right), told NR Times: “What we observed in our functional MRI studies is that in our placebo control group, repeated physical therapy is only able to continually activate the premotor cortex.”

“But the problem with that activation is that over time, you exhaust that ability, so in fact, you see an improvement, and then over time you start seeing a decline.”

Using the tongue as a gateway to the brain

Consisting of a controller worn around the neck and a mouthpiece, PoNS therapy works by stimulating a specific part of the tongue with electrical pulses, also known as translingual stimulation.

96 gold-plated electrodes deliver small amounts of electrical stimulation to the anterior dorsal part of the tongue, producing a sensation similar to drinking carbonated water.

The device delivers 200 pulses per millisecond, but how do these tiny electrodes placed on the tongue affect patients’ ability to walk?

The PoNS device delivers electricity to a specific layer of the tongue, between 300 to 400 micrometres from the surface.

This particular part of the tongue contains fibres from two important cranial nerves.

One is the lingual nerve, a branch extending from the larger trigeminal nerve which is responsible for sensation and movement in the face and mouth.

The other is the chorda typani, a branch of the facial nerve which transports information to the brain from the tongue about sensations like pain, temperature and taste.

These two nerves are significant as they are the only cranial nerves with both sensory and motor functions.

More importantly, the chorda tympani and the lingual nerve have a direct connection with the cerebellum, also known as the brain stem.

The brain stem acts as the control centre for regulating the body’s automatic and voluntary movements.

Travelling through the cranial and chorda tympani nerves, the electrical stimulation connects to specific areas of the brain stem which in turn activates multiple cortexes in the cerebrum.

This means PoNS therapy engages with not only the premotor cortex but also the dorsolateral prefrontal cortex, the cingulate cortex and the motor cortex, areas of the brain that physical therapy alone is unable to reach.

“When you do translingual stimulation and you are selectively activating the cerebellum and the brainstem,” Dr Favit-Van Pelt said, “you’re going to engage those centres that are responsible for overall coordination.”

What is groundbreaking about translingual stimulation is the ability for devices like PoNS to be used in tandem with physical therapy.

Other stimulation technologies predominantly rely on transcranial devices.

While effective in inducing neuromodulation, the delivery method is cumbersome and usually takes place in labs with little space to move.

Dr Favit-Van Pelt explained: “The problem with other technologies – namely transcranial since this is the most established form of stimulation – is yes, they induce neuromodulation but in order to trigger adaptive changes that lead to compensatory mechanisms, they need to be used consistently and they need to be used with the function you want to rehabilitate.

“You need to actually have the patient performing the task that you want to rehabilitate.”

MS is just the start

Originally developed as a technique for eliciting memories of images in sight-impaired patients, early research on translingual stimulation found that blind patients with balance conditions also gained confidence in their gait.

Subsequent research found that the longer participants engaged with the therapy, the longer the effect on their balance lasted.

When researchers discovered that translingual stimulation had the potential to repair pathways in the brain, the prospect of using the technology in a neurorehabilitation setting laid the groundwork for what would later become PoNS.

In the US PoNS is primarily being used to treat gait deficit in patients with multiple sclerosis, however, clinical research data show that the therapeutic response is consistent across other neurologic conditions.

According to Dr Favit-Van Pelt, the potential of the technology extends far beyond the current indications.

“We have evidence of therapeutic benefit in North America, namely in the US and in Canada,” said Dr Favit-Van Pelt.

“What we have observed from treating patients with PoNS therapy is that regardless of whether we have studied it in patients with MS or with TBI or with stroke, we observe the same type of improvement in gait and balance.

“When we looked at the gait assessment measures or balance assessment measures, we always [saw] the same amplitude of improvement. The therapeutic response is consistent.

“This means that this therapy is likely to up-regulate systems that control movement and coordination potentially regardless of the underlying condition.”

From wheelchair-bound to walking

Helius has reported an 80 per cent response rate from patients according to clinical data, while anecdotally, over 60 per cent of patients using the PoNS right now are reporting a benefit.

According to Helius, most patients experience at least five points of improvement on MS assessment scales, notably the dynamic gait index (DGI) and the functional gait index (FGA).

In one of two clinical studies conducted by the FDA, results showed that a group of 10 patients on average achieved improvement in their DGI score of 7.95 at the end of the study, while the control group did not.

In reality, an improvement score of this amount could be the difference between a patient needing poles to walk and not needing any walking support at all.

Dr Favit-Van Pelt stresses that PoNS is more than just a device, it is a therapy which produces the best results when used in conjunction with physical therapy.

“The aim here is not to get a patient to walk perfectly,” Dr Favit-Van Pelt said.

“This is a therapy, not just a device and it delivers functional improvement on people’s disability.

“We’re seeing people who were able to move from almost wheelchair-bound to walking with a cane.

“A seven-point improvement on a patient that comes from that standpoint is extraordinary.”

The impact of translingual stimulation on patients

PoNS has been used by patients since 2019 following its authorisation in Canada for use, in a supervised setting, as a short-term treatment for gait deficit in mild to moderate MS, and stroke symptoms and for balance deficit in mild to moderate TBI. The device was also authorised in the US in March 2021 for similar use on gait deficit in people with mild to moderate MS.

The device was also authorised in the US in March 2021 for use in a supervised therapeutic setting.

Anna Sweeney, a dietician in Massachusetts, has experienced significant improvement in her gait using PoNS.

Having lived with MS for almost 25 years, she has tried numerous therapies and enlisted the help of various different specialists to help slow the progression of the condition, but she had little success until she began a course of PoNS therapy.

“As my disease has progressed and my disability has evolved, I have gone to great lengths to do anything to pause or halt the process,” Sweeney told NR Times.

“I’ve changed medications, I have sought care and support from all types of practitioners, I have worked and tried very hard to regain abilities that I’ve lost, and until PoNS, I have been unsuccessful.

“All things being relative, I am moving more quickly than I have in years. I have always been a fast walker and in this moment, I am walking much faster than I ever thought I would again.

“I move more confidently and naturally, something that I didn’t realise I had lost until I regained it.”

Sweeney was given training in the physical therapy regimen using PoNS by Dr Naseem Chatiwala, a neuroclinical physical therapy specialist.

Dr Chatiwala is a self-described PoNS convert. She initially doubted the technology after seeing a marked improvement in Anna’s ability to walk, she now intends to use the device with other patients.

“As a physical therapist, I have worked with many patients with neurologic deficits,” Dr Chariwala said. “When I heard about PoNS I had doubts that tongue-based electrical stimulation could effectively retrain the brain to improve walking ability.

“But as I worked with Anna, the improvement was undeniable. I’m excited about using PoNS with more patients.”

Sweeney describes PoNS as the “best thing that has happened” to her since being diagnosed with MS.

“I wish I had PoNS when disability became a part of my life and I am so grateful to have it now,” she said.

“Singularly, it is the best thing that has happened to me since I started losing function due to MS. I’m still very disabled. I always will be, [but] I’m a faster walker again.”