Regardless
of severity, recovery from stroke or spinal cord injury (SCI) is always
a challenging process. This is especially true when the patient’s hands
are affected.
Because
standard physical rehabilitation tends to prioritize therapies focused
on walking and the lower extremities, there’s an unmet need among those
trying to recover the use of their hands, said Chad Bouton, founder and
CEO of Neuvotion, an early-stage medical device company that develops
neuromodulation technologies and products for neurorehabilitation,
brain-computer interfaces, and physical therapy.
“The
hand is very complicated – there are many joints, over 30 muscles
involved, and the hand has a large number of degrees of freedom,” Bouton
told MD+DI.
“With the complexity of the hand, that part of the brain is a bit
larger – so there is more susceptibility for a stroke to compromise a
patient’s hands. And with spinal cord injuries, we also often see a lot
at the neck level that unfortunately affects the hands. Recovery can be
challenging, but that’s what we’ve been focused on.”
Founded
in 2019, Neuvotion’s first product, NeuStim, a non-invasive,
surgery-free, high-precision wearable that electrically stimulates
muscles, has received 510(k) clearance.
The
device supports hand movement recovery after stroke or SCI through the
use of a touchscreen interface that enables clinicians to scan and
pinpoint muscle targets electronically to steer stimulation with
precision.
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The
wearable is expected to launch within the next year and help produce
improved outcomes in stroke and SCI rehabilitation with the potential
for earlier intervention depending on how quickly patients are
stabilized.
“The
responses that we are already receiving from clinical institutions
around the world have been very exciting,” said Bouton, who prior to
establishing Neuvotion developed and led the technology involved in the
world’s first study on a paralyzed patient who regained hand function through the use of a brain chip that was linked to muscle stimulation in real-time.
Stimulation as soon as possible
Intended
to treat adult patients who have experienced a hemiplegic stroke
(paralysis or paresis on one side of the body) or those who have had a
SCI at the fifth cervical vertebra (C-5 level), the NeuStim device can
be initiated as early in the rehab process as the clinical care team
deems appropriate if the necessary clinical requirements for receiving
electrical stimulation are achieved. Evidence suggests that the timing
of intervention can play a role in outcomes, according to Bouton.
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“Our
research has shown that when you can start patients on the therapy
earlier if they’re ready, that can help to reverse atrophy and
maladaptation of the neural circuits – these motor circuits that over
time can start to develop ‘bad habits’ because of impaired function,” he
said.
A
wireless, standalone, battery-operated device, NeuStim allows the
clinician to communicate instructions for stimulation from a tablet
interface to the patient once the wearable has been placed on the
affected arm. By sliding a finger over the touchscreen, the clinician
can move the point of stimulation via more than 150 small electrodes
that deliver electrical impulses to the muscles noninvasively through
the skin. Patches that are placed on the skin light up to indicate where
the stimulation point is moving electronically.
“The
electrodes do not need to be moved manually in the conventional way,”
Bouton said. “That method can take hours away from the rehab sessions to
map everything. It can also be much more difficult to find motor
points. But with our approach, we have demonstrated that you can touch a
screen to accomplish this task – and within minutes you can find the
motor points, stimulate the right muscles, and literally get patients
moving again. Insurance covers only a certain amount of time for
rehabilitation. You don’t want to be spending more time on setup.
NeuStim can be placed quickly, in under 90 seconds.”
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Device design and delivery
Developmentally
focused on efficacy and safety, NeuStim’s design and functionality are
the result of a collaborative partnership between Neuvotion and
Intelligent Product Solutions (IPS), an end-to-end company that
specializes in medical device design and development.
While
there are a few contraindications and warnings related to receiving
electrical stimulation that must be considered before beginning the
therapy, including the use of synchronous (or demand) pacemakers and
implantable cardiac defibrillators, the device has been designed for a
variety of patient anatomies, according to Brad Carlson, vice president
of technology and business development at IPS.
“There’s
a human element here and we wanted ease of use to lead to adoption,”
Carlson said. “To ensure safety, we have used biocompatible materials
throughout the design. The device maintains safe stimulation levels on
its own with built-in safety mechanisms to maintain proper operation.”
Stimulation should not be applied over the carotid sinus nerves, particularly in patients with
a known sensitivity to the carotid sinus reflex.
Another innovative design aspect of the device is the thin, flexible patches that hold the electrodes in place.
“This
promotes contractions of the muscles after stroke or spinal cord injury
to reverse that atrophy and to promote rehabilitation or recovery over
time,” said Bouton.
The
specificity at which stimulation can be delivered has been especially
important in stroke recovery. “When you’re talking about the hand and
finger movements, these are very small muscles and muscle targets,” said
Bouton. “With stroke, hypertonicity will commonly occur, and patients
will have excessive flexion. And it’s difficult to counteract that with
conventional therapy when you’re only trying to mechanically move
something. But if you electrically stimulate the opposite side and you
can pinpoint those targets, those muscles can be activated and you can
get movement. Sometimes there’s a response within seconds.”
To
promote continuity, stimulation profiles can be established and saved
for each user through the graphical interface. Patients are engaged by
watching the impulses that are sent by the clinician and providing
instant feedback about anything that they’re able to sense or feel
during the therapy, although sensation could be impaired, especially in
SCI cases.
“Once
the clinician is set up and they have found those stimulation points,
and we’re seeing muscle activation and movements, they can then save
those patterns into the device for that patient,” Bouton said. “This is a
great feature because when they come in for future sessions their
settings can be loaded and repeated. We can then store those sequences
that the clinical team wants to work on – say, the opening of the hand
and the closing of the hand, or transfer tasks such as picking up
objects and putting them down, or compound movements. This device has
the advanced feature of having these sequences so that patients can be
helped with doing functional movements. And research has shown that if
the patient is actively involved in their therapy, the outcomes are
better.”
With
stimulation information stored, the clinician utilizes a slider on the
touchscreen that resembles a volume control to adjust the intensity or
level of stimulation. There’s also an option to modulate the stimulation
setting, allowing for the intensity to be adjusted up and down, which
contracts the muscle at different levels – something that’s effective
for trying to slow down or reverse any atrophy. This is also beneficial
for activating the muscles in the neural circuits to help promote
recovery, according to Bouton. “The patients can also be actively
involved in attempting these movements, which is common in a rehab
setting. But the difference here is the stimulation can be steered
electronically, and the levels can be adjusted in real-time,” he said.
Bouton
credits the collaboration with IPS with helping to design the device to
offer this level of sophistication. “IPS has been an extension of our
engineering team, and they have been fantastic to work with,” he said.
“Patients have different forearm shapes and sizes. IPS was instrumental
in looking at different sizes and shapes of arms with their human
factors team, which was a big challenge that helped us to shape and size
the design to fit unique anatomies. To be able to keep the device thin,
flexible, and fitting has been a fantastic design element that IPS led.
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Future features already being researched
Bouton said Neuvotion has been focused on the next innovations for NeuStim prior to the device appearing on the market.
“Something
that is currently under development in our system as a future feature
is adding artificial intelligence that will allow patients to start a
gross motion that the AI will recognize and infer that they’re trying to
open their hand — and to automatically stimulate the hand to pick up an
object,” Bouton said. “We’ve completed early research studies and we anticipate adding this technology in the coming versions.”