Brain implant deciphers finger movements in paralyzed patient, allowing video games to be played

A surgically implanted brain-computer interface enables precise finger control in a paralyzed patient, paving the way for social and leisure activities such as video games

In a study published in Nature Medicineresearchers recently designed a brain-computer interface that can be implanted in the brain to continuously detect and decode finger movements in people with Paralysis, allowing them to play video games.

Context

Severe motor disorders or paralysis are often associated with a multitude of disabilities that can impair individuals’ physical and mental well-being. In the United States, more than five million people live with paralysis.

A recent survey in the United States indicates that approximately 79%, 50% and 63% of people with spinal cord injury paralysis have unmet needs for peer support, leisure and sports.

People with mild or moderate motor disorders, capable of handling a video game controller, often use video games to create social connections and have a competitive space. However, those with severe motor impairments face significant barriers when it comes to playing video games, even with assistive technologies. They are often forced to play at a lower difficulty level or avoid multiplayer games with people without disabilities.

Brain-computer interface systems are attracting increasing interest as potential interventions to restore motor activities. These interfaces can help paralyzed people control video games and, more broadly, digital interfaces for social networking and remote working.

Although robotic arms have attracted much attention in the field of brain-computer interfaces, aimed at reaching and grasping objects by moving fingers in groups, interfaces designed to provide individual finger control would enable varied activities such as typing, playing a musical instrument or operating a video game controller.

Study results

In this study, researchers developed a brain-computer interface to continuously decode three independent groups of fingers. The thumb was decoded into two dimensions, ultimately providing four degrees of freedom.

The interface was able to continuously record patterns of electrical activity from multiple neurons in the brain and translate those signals into complex movements.

It was implanted in the left precentral gyrus of a person suffering from quadriplegia (paralysis of the upper and lower limbs) following a spinal cord injury, this region being responsible for controlling hand movements.

The scientists recorded neural activities while the participant observed a virtual hand moving in various ways on a screen. They analyzed these recordings using machine learning algorithms to identify signals related to specific finger movements.

The brain-computer interface system used these signals to accurately predict finger movements and subsequently allowed the participant to control three very distinct groups of fingers in a virtual hand, including two-dimensional movements of the thumb.

The system thus achieved a higher level of precision in finger movements than was previously possible.

The researchers then extended this finger control application to a video game. They used finger positions decoded by the interface to provide independent digital points to control the speed and direction of a virtual quadcopter, allowing the participant to pilot the device through multiple obstacle courses within the framework. of a video game.

The participant expressed a feeling of social connection, empowerment, and leisure when controlling the quadcopter through the brain-computer interface. He also emphasized the importance of individualization of finger movements, explaining that a lack of this individualization degrades performance.

Significance of the study

This research highlights the development and validation of a high-performance brain-computer interface system based on finger control, capable of addressing many unmet needs of paralyzed people.

The majority of previous studies have focused on the use of brain-computer interfaces for the control of two-dimensional cursors to regulate a quadcopter or flight simulator. One study reported that a quadcopter controlled by electroencephalography successfully navigated through 3 circles in 4 minutes, compared to 12 circles for able-bodied individuals using a keyboard.

In contrast, the present study demonstrated that the brain-computer interface system enabled navigation through 18 circles in less than 3 minutes at optimal performance, indicating a six-fold performance gain.

This system also allows free and spontaneous flight through randomly appearing rings. This approach using fine motor control for video games controlled by an intracortical brain-computer interface could address many unmet needs of paralyzed people.