December 5, 2023

Engineers at ETH Zurich have developed a wearable system that could help patients regain mobility after a stroke. The system consists of a motion-sensing watch and a headset that stimulates nerves to help rewire neural circuits.

After a stroke, interrupted blood flow can cause neurons in the brain to die, reducing a person’s ability to move. Depending on which brain area is affected, they may have trouble moving their limbs, walking, talking, or grasping objects.

While many treatments focus on minimizing or reversing the damage done to neurons, others take advantage of the brain’s incredible plasticity‚ÄĒessentially, its ability to rewire itself beautifully to form new connections . This may bypass the damaged area and restore some motor function.Some techniques use drugs to do this, and more and more jobs Focus on vagus nerve stimulation (VNS).

This technique involves using low electrical pulses to disrupt major nerves in the parasympathetic nervous system, which controls involuntary bodily functions such as heart rate and digestion. VNS has been tested to treat conditions as diverse as epilepsy, depression, chronic indigestion, rheumatoid arthritis and even aging itself.

Patients usually undergo surgery under general anesthesia to implant small devices that stimulate fuzzy nerves, but this is of course quite invasive. Dubbed Smart VNS, the new ETH Zurich system aims to simplify use by turning it into a mobile wearable device consisting of a headset and an exercise-tracking watch.

“Our headset sends out subtle electrical impulses to activate the nerves in the outer ear, eliminating the need for surgery,” said Paulius Viskaitis, a co-developer of the system.

Researcher Dane Donegan demonstrates the Smart VNS system in action
Researcher Dane Donegan demonstrates the Smart VNS system in action

ETH Zurich / Donegan and Viskaitis

The watch, meanwhile, tracks the movement of the limb using an inertial measurement unit (IMU), much like you’d find in a smartphone, and when it senses movement, it instructs the earphones to stimulate the nerves. The idea is to use reinforcement learning to train the brain to find new ways to perform movements interrupted by stroke damage. So the user places the watch on the affected limb, and when they successfully move it, the electrical impulses generated strengthen the neural circuits that make that movement possible.

Over time, the brain should get better at performing these movements, helping patients regain more motor function more quickly and efficiently. Results with more invasive VNS implants have been promising, so the team hopes theirs will do the same. Even better, unlike other stimulation implants, this treatment can be done by the patient themselves without medical supervision. The smart VNS system can also save the patient’s progress data on the smartphone, so the physiotherapist can remotely monitor it in detail.

The team plans to conduct more tests on healthy subjects before launching clinical trials. More details can be seen in the (business term) video below.

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Headphones to speed recovery after stroke

source: ETH Zurich