Ever since quadriplegic Jan Scheuermann used a mind-controlled robotic arm to eat a bar of chocolate back in 2012, Brain Control Interfaces (BCI) have been touted as a promising technology that could give others like her a new lease on life. However some critics say that for all its life-changing potential, it is also potentially dangerous as most of the devices used in clinical trials so far require the use of surgical brain implants. Researchers at the University of Minnesota could help to quell those fears while advancing this field further with their latest breakthrough: a mind-controlled robotic arm that requires no surgical implants.
The electroencephalography (EEG)-based BCI device developed by the University of Minnesota researchers incorporates an EEG cap fitted with 64 electrode sensors to interpret brain signals and convert them into action. While wearing the cap, test subjects first learned to control a virtual cursor on a computer screen, and then a robotic arm to reach and grasp objects in fixed locations on a table. After this, they were able to control the robotic arm with their minds, and use it to reach and grasp objects in random locations on a table and move them to a shelf.
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The success rate was promising: 2,000 trials were conducted in an eclectic range of environments, and the subjects succeeded more than 80 percent of the time when picking up objects from a fixed location and more than 70 percent when placing them on a shelf.
"This is the first time in the world that people can operate a robotic arm to reach and grasp objects in a complex 3D environment using only their thoughts without a brain implant," says lead author Bin He, a biomedical engineering professor at the University of Minnesota. "Just by imagining moving their arms, they were able to move the robotic arm."
The researchers say understanding the geography of the motor cortex – the area of the cerebrum that governs movement – is key to making BCI technology work. While individuals might lose their ability to move and control their muscles, most of them, even those with severe neuromuscular disorders or damage to the motor system, retain the ability in the brain to produce motor function-related neural activities, explain the study's authors. This is why BCI is seen as a bridge between the brain and the outside world.
When humans move, or think about a movement, neurons in the motor cortex produce tiny electric currents. Crucial to the success of this study was the ability of the sensors in the cap to filter out background noise and pick up the neural signals the brain was sending.
"We figured out how to pick up the real brain signal out of the huge background noise ... and decode its intention," He told the Star Tribune.
The study builds on his previous research, in which subjects used noninvasive EEG technology to fly a drone. The goal back then was the same as it is now: to develop robotic prostheses that would restore the autonomy of paralyzed individuals or those with neurodegenerative diseases without a need for surgical implants.
"Three years ago, we weren't sure moving a more complex robotic arm to grasp and move objects using this brain-computer interface technology could even be achieved," He says. "We're happily surprised that it worked with a high success rate and in a group of people."
Neuroscientist and engineer Jose Luis Contreras-Vidal, whose research team at the University of Houston developed an EEG-based bionic hand, told New Atlas that this new study adds to the evidence that EEG is an adequate source signal for developing neuroprostheses. But since the tests were conducted on able-bodied individuals, what will be of special interest are the results of clinical trials conducted on the technology's target audience.
While prosthetic technology has come a long way from the metal hook – amputees currently have options such as the Star Wars-inspired Luke Arm – there are still limitations to what they can do and who they can serve. The Luke Arm, for instance, cannot be used by people with limb loss occurring at the elbow or wrist joint. In comparison, BCI-enabled devices would be able to benefit a lot more people, especially those with stroke or severe spinal cord injuries. A non-invasive option would be an added bonus, as it would do away with the risks and costs associated with brain surgery.
Until this becomes a reality, here's a video demonstration of the test subjects controlling the robotic arm with the EEG cap:
The results of their study were published in Scientific Reports.
Source: University of Minnesota