Brain-computer interfaces (BCIs) are being developed to help individuals with paralysis participate more fully in life, including through activities like video games that they can control with their minds. A team from Stanford and Michigan universities successfully enabled a paralyzed individual to control a quadcopter using a BCI. This study was peer-reviewed and published in the journal Nature Medicine.
BCIs are still often imprecise. In the United States alone, over five million people live with severe motor impairments. Many of these individuals turn to video games for recreation, as they offer various ways to participate without using hands. BCIs are seen as the next step in allowing sophisticated control of video games. However, many BCIs still struggle with accurately interpreting individual finger movements, making them too imprecise for many applications.
The team led by neurosurgeon Matthew Willsey developed a BCI that achieves a higher level of movement precision and freedom than previously possible. The BCI, with its microelectrodes, was implanted in the precentral gyrus of a nearly completely paralyzed 69-year-old patient, referred to as T5. This brain area includes the motor cortex, which controls hand and finger movements.
To train the interface, the patient watched a virtual hand perform various movements and imagined performing the same movements with their own hand. The corresponding neural signals were recorded and analyzed using machine learning algorithms, or artificial intelligence, to identify which signals corresponded to which finger movements.
The difference from previous studies was that this interface was not only designed for simple motor tasks like clicking a mouse or grabbing an object but also for representing complex finger movements in a multidimensional space, like those needed in video games or for flying a quadcopter.
In subsequent tests, T5 was able to move three finger groups and the thumb of a virtual hand, linked to the remote control of a virtual quadcopter, using only the power of thought. T5 could steer the quadcopter left, right, up, and down using just the thumb. The patient navigated the quadcopter through a predetermined obstacle course and through spontaneously appearing rings. Overall, the system allowed navigation through or around 18 rings in less than three minutes, a sixfold improvement over previous systems. However, the system was not infallible; different finger groups were sometimes activated simultaneously, complicating control.
The patient, who had expressed a desire to fly a quadcopter again, described the experience as playing a musical instrument: “Imagine playing a clarinet and picking up someone else’s instrument. You immediately notice it’s different, but thanks to your experience, you adapt accordingly.” The flight control was “more sensitive than fingers,” and he only needed to “nudge it in a direction.”
For Matthew Willsey and his colleagues, this research represents the next step in involving paralyzed individuals more in recreational activities. Video games have become a litmus test for the capabilities of BCIs. Elon Musk’s startup Neuralink introduced a BCI that reportedly allowed a patient to play Counter-Strike. Additionally, a team from the University of Texas in Austin demonstrated that the brainwaves needed for gaming can be analyzed non-invasively using EEG caps.