Twitch streamer and YouTuber Perrikaryal came into the limelight on X in June with her viral video of defeating the first boss from the game Elden Ring’s Shadow of the Erdtree through “mind control”, which uses devices recognising brain activity and eye movements to control.

In the clip, the creator’s live footage of staring at her monitor is displayed next to her in-game character beating Divine Beast Dancing Lion, known as one of the most challenging bosses in the game’s latest expansion. The video has garnered more than 49K likes on the platform, followed by congratulatory remarks from fellow gamers in the comments.

“People are interested in the tech and are very complimentary to me and my project,” the United Kingdom-based streamer, who goes by the name Perri, told 4i Magazine.

“Of course, there is a crowd of non-believers but I find that encouraging because it tells me that this sort of thing is fringe experimentation and that’s exactly where I want to be.”

‘Mind Control’ gaming technology, explained

Perri’s career as a content creator started about three years ago when she was studying psychology in her master’s programme. Driven by curiosity and passion for technology-powered tools and psychology, she has been taking on various projects of psychology-tech experiments, including her latest mind-control gaming system.

The main device of the system is a 14-sensor headset that can pick up Perri’s brain activity, known as an electroencephalogram (EEG), which is primarily designed for diagnosing epilepsy. The device is built by bioinformatics and technology company Emotiv, whose flagship products include EEG devices and brain-computer interface (BCI), which Perri also uses.

The imagination is the key driver of her system. “Your brain looks different when you’re imagining doing different things,” Perri said. “I can record the EEG data for ten seconds at a time when I’m imagining doing something. I do that over and over again until it recognises that pattern of brain activity.”

The recognised patterns are sent as signals to a virtual Xbox controller that Perri has. The BCI that she uses now can record only four mental commands and cannot compute more than one command at a time. Perri says she is currently working with Emotiv to improve the system and is using some voice commands to fill the gaps between.

The virtual controller’s joysticks are controlled through her eye movements and gyroscopic motions tracked via her installed camera.

Opportunities and challenges of mind control controller

Being a virtual controller, Perri’s setup can be played on any gaming title. She can also execute mental commands from a dropdown menu from the software, allowing her to hold or spam them by clicking on the buttons. Just like any Xbox controller, her controller can also be used outside of games, like opening apps. Although it was by accident, Perri once opened her email and Whatsapp on livestream using her virtual controller.

Perri says that her virtual controller has a few drawbacks that need improvement. One is the EEG headset itself, which requires readjustment now and then. The saline solution-soaked pads that read her brain activity can also dry out in the middle of gameplay, resulting in false positives and negatives.

Producing the same brain pattern to move the controller is not easy, either.

“I often stood still in front of a boss while doing nothing, because I couldn’t heal myself or attack it,” she said. “It requires a great deal of concentration to conjure the same pattern of brain activity. If I’m feeling stressed or not paying attention to the game, the controls may not work (by my intentions).”

Because her EEG has relatively few sensors, it is limited in reading brain activity accurately. Electromagnetic activities that are not from her brain can sometimes interfere with the headset, too.

“It’s a tricky thing to control, but gets a lot easier with practice,” Perri said.

Next goal for the inventive gamer

While there is no immediate plan to introduce her virtual controller, Perri says it may be possible sometime in the future. At the moment, her goal is to improve the existing system for a better gaming experience.

“I’m working on using two BCIs simultaneously, which will double the amount of input and allow me to push multiple buttons at a time,” Perri said. “This would open so many doors to make a purely mind-controlled game controller without peripheral techs like eye tracking and voice commands.

“I look forward to developing, improving, and pushing this, as far as it’ll take me.”