A research team at Ohio University has enabled a man suffering from quadriplegia to regain partial use of his right hand, using signals recorded by an implant that was surgically placed in his brain. "For the first time, a human with quadriplegia regained volitional, functional movement through the use of intracortically recorded signals linked to neuromuscular stimulation in real-time," the study’s text proclaims.
Ian Burkhart, now 24, broke his neck six years ago in a swimming accident, resulting in his paralysis. Two years ago, he underwent the procedure to have an implant inserted into his brain’s motor cortex, where the device picks up on the signals that would ordinarily be sent to the rest of his body to activate his muscles.
Burkhart’s brain activity was then recorded by the research team, while he imagined performing specific physical actions. The recorded signals were applied to machine-learning algorithms, to determine which signals were meant for the intended individual motions, and are then transmitted to a special sleeve on Ian’s arm. The sleeve is embedded with an array of electrodes that stimulate specific muscle groups that control his hand, offering him a surprisingly useful range of six different functions.
Through the device, Burkhart can now do things like grasp and move objects, pour water from a glass, swipe a credit card, and even use the guitar-shaped controller for the video game, Guitar Hero. Use of the implant initially gave him headaches; it can only be used in the laboratory; and unfortunately offers no feedback or feeling from the animated limb. This new technique, however, offers a greater range of movement over earlier EEG or EMG-based techniques.
The research paper explains the limitations of previous techniques: "These devices typically allow control over fewer movements than those demonstrated in this study, because of the relatively low information content of their control signal sources compared with intracortically recorded signals." This means that the big difference with this technique is that it records the signals directly from the brain’s motor cortex, providing much more detailed signals, where previous techniques would only record muddled signals from outside the subject’s cranium.