A wheelchair controlled by thoughts

Quadriplegics cannot move their bodies from the neck down. Often, but not always, due to a traumatic injury the connection between the brain and nervous system is disrupted. Without this connection, the brain cannot command the legs to move.

The wheelchair, developed by researchers at the University of Texas at Austin, could help these people by having their brains do this with the chair itself and guide it wherever they want, even though it can’t “talk” with its legs.

WheelchairiStock

“Mind-controlled wheelchairs are an interesting assisted mobility solution that can be applied in cases of complete paralysis,” the researchers say. iScience. “We showed that three quadriplegic users with spinal cord injuries can be trained to use a non-invasive wheelchair, and controlled by thought and execute complex navigation tasks,” they explain.

This isn’t the first time a thought-driven mobility aid has been offered. But as the researchers point out in their publication, the wheelchair has been tested by tetraplegics and also works with certain considerations. Most of the previous projects have been tested by people who do not suffer from quadriplegia and are activated by the user’s responses to stimuli.

Robotic intelligence and motion-specific brain activity are combined in the new wheelchair. This means that the person using it can think of something else or talk to someone and the chair will remain stable. He will only act when he is clearly told what to do. And how is this achieved?

Researchers trained chair testers to move the chair by imagining that they were moving their hands and feet; this may sound strange as tetraplegia is characterized by the inability to do exactly that. But it’s not because the brain can’t send the commanding messages, it’s because they get lost along the way.

With all this in mind, the researchers considered designing a device that could read brain activity, for example an electroencephalogram to be worn in the form of an electroencephalogram. electrode cap. The device will be able to capture these signals and send them to be interpreted as movement orders.

In addition, they will add sensors who will be wheelchair bound and computer program translating what is seen as information from the environment. The latter would be like a kind of safety mechanism that prevents the chair from hitting the wall, for example because the person is thinking of turning left.

“It works very much like riding a horse,” says José del R. Millán, who led the project. “The driver can tell the horse to turn left or turn to a door. But the horse will eventually have to find the most appropriate way to carry out these commands.”

Therefore, chairs can be used. without the need for any invasive procedure, it will only be necessary to attach the electrode head and review the training manual. The electrodes are designed to be used for a long time without replacement. The chairs have been tested in natural environments, including messy ones, so bringing them into real-world situations shouldn’t be too difficult.

“We show that people who would truly be end users of this type of device can navigate in a natural environment with the help of a brain-machine interface,” added Millán.

The downside is that it should be taken into account that The study was carried out with only three people., one of which fell short of what the authors considered “high scanning performance.” All three were patients with spinal cord injuries, which limits the generalization of results to anyone with a different profile.

Reference: Tonin, L., Perdikis, S. et. for. Learning to control a powered wheelchair with BMI for people with severe tetraplegia. 2022. iScience. DOI: https://doi.org/10.1016/j.isci.2022.105418

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