A streamer named Perrikaryal has managed to play a video game with her thoughts. By connecting her brain to a computer using a wireless headset, she beat part of a notoriously difficult game with her mind.

Our brains contain billions of neurons, each of which connects with thousands of other neurons. They use either electricity or chemicals to “communicate” with one another. Our brain works in different ways when these signals activate different patterns of neurons. (A more detailed explanation can be viewed here.)

EEG (electroencephalography) machines are medical devices used to detect these electrical patterns in the brain over time. This information is useful to diagnose medical conditions such as epilepsy and sleep disorders.

The electrical signals that EEGs detect can also be used to recognize specific thought patterns. In 2022, researchers scanned a monkey’s brain while it moved a joystick in different directions to play a simple video game. By doing so, they could identify what signals its brain gave off when the monkey wanted the ball to move in each direction.

By continuing to monitor these brain waves after the joystick was unplugged and removed, the monkey could continue playing a simple game with just its thoughts. The software learned to respond to the “I want the ball to move up” signal by moving the digital ball upward, and so on.

This technology has advanced rapidly—a man in 2019 was able to play video games by using similar medical devices implanted in his brain. This was effective, but impractical for anyone who does not want physical hardware surgically installed in their heads.

Perrikaryal resolved this problem by using a portable and wireless EEG. When she puts the device on her head, it looks for different brain waves and sends a corresponding signal to a computer. Perrikaryal cleverly connected each of these outputs to a different action in a game.

This is a more sophisticated and less invasive adaptation of the technology the Pong-playing monkey used. Like the monkey, she can communicate her intentions to the machine by thinking in different ways. (A demonstration of this can be viewed here.) She astounded live viewers in January 2023 by using this setup to play the punishingly difficult game Elden Ring.

Perrikaryal currently only uses the EEG to operate two buttons, which direct her character to “attack” and “heal.” All other actions are still controlled manually, but she plans to continue adding more sophisticated functions to mentally control most or all of the game.

Her success is particularly exciting for disabled people,* some of whom have difficulty playing video games that require manual dexterity. Even with modified controllers, people with paralysis or limb differences cannot play as deftly as they would like. An EEG headset could remove this barrier, level the playing field, and let everyone enjoy the numerous social and emotional benefits of gaming.

*Many disability activists prefer being called “disabled” rather than “people with disabilities.”