People with paralysis use a mind-controlled wheelchair to explore a room.

Three persons with quadriplegia navigated a congested environment using a mind-controlled wheelchair with reasonable precision.

Three persons with quadriplegia utilised their thoughts to guide a wheelchair across a congested environment with a great degree of precision. This implies that persons with paralysis may be able to walk around freely in some spaces, but the technology may not be mature enough to manage a crowded street.

Previously, a variety of studies employed two major ways to test mind-controlled wheelchairs on non-disabled persons. The first involves a person focusing their attention on a flashing light in a specific spot. This produces brain signals that an artificial intelligence translates into wheelchair motions toward that area, however this method frequently causes eyestrain.

The second approach entails implanting electrodes in the brain. These accurately communicate brain impulses to artificial intelligence, but only after a fairly invasive surgery that risks infection.

José Millán of the University of Texas at Austin and his colleagues tested a third technique by recruiting three persons who had little or no mobility in either of their limbs. The researchers investigated whether a brain-computer interface might drive an electric wheelchair using brain activity generated when people imagined moving their limbs.

Each subject wore a skullcap with 31 electrodes that could detect signals from the sensorimotor cortex, a brain area that governs movement. These signals were sent to a laptop mounted on the wheelchair's back, where an AI converted them into wheel motions.

Users imagined moving both arms to the right to move. They imagined shifting both legs to the left. Otherwise, the wheelchair advanced.

In the two other methodologies used to steer mind-controlled wheelchairs, the ability to operate the chair is mostly determined by how successfully brain-computer interfaces gather and interpret brain signals from a user during a few hours of training and testing.

In the most recent study, the researchers trained individuals to create clearer brain signals during a two to five-month period, with three training sessions each week.

The researchers instructed the participants to order the wheelchair to go left or right 60 times on average throughout each session.

"Person 1" received accurate orders 37% of the time on average throughout their first ten training sessions, climbing to 87% accuracy by the last ten training sessions.

"Person 3's" steering accuracy increased as well, rising from 67% to 91%. During their training sessions, "Person 2" consistently directed with an average accuracy of 68%.

"There will be those who learn it quickly and well, and others who will require more time to learn, such as Person 2, but I believe everybody can learn to do it," Millán adds.

The scientists discovered that by analysing the individuals' brain signals during the training period, the "left" and "right" brain signals of Person 1 and Person 3 grew more different.

The researchers assessed the participants' ability to manoeuvre the wheelchair through four checkpoints in a 15-metre hospital room filled with beds, chairs, and medical equipment.

Person 1 completed the circuit in around 4 minutes, with an average success rate of 80% across 29 attempts. Passing through the circuit checkpoints was considered as success.

Person 3 completed the circuit in around 7 minutes, with an average success rate of 20% over 11 attempts. Person 2 completed the third checkpoint in roughly 5 minutes on 75% of their efforts but was unable to finish the entire course.

"I wouldn't suggest the method is appropriate on busy streets or in less regulated surroundings," Millán adds, "but being able to move independently at all can be a big advantage to these people."

The skullcap, however, must be adhered to the head using a gel that dries out after a few hours, limiting the amount of time the wheelchair may be operated at one time.

According to Palaniappan Ramaswamy of the University of Kent in the United Kingdom, the usage of gels may one day be removed due to quick improvements in dry and skin-printed electrodes, as well as those that fit into the ear. Combining this current study with gel-free technology, he claims, might usher in mind-controlled wheelchairs into the real world within the next decade.