In a brand-new study, scientists show that tetraplegic users can run mind-controlled wheelchairs in a natural, cluttered environment. The mind-controlled wheelchair assists paralyzed people gain brand-new mobility by equating users thoughts into mechanical commands.
By translating users thoughts into mechanical commands, a mind-controlled wheelchair can help a paralyzed individual gain new mobility. Researchers show that tetraplegic users can run mind-controlled wheelchairs in a natural, messy environment after training for an extended period in a study published today (November 18) in the journal iScience.
” We reveal that shared knowing of both the user and the brain-machine interface algorithm are both essential for users to successfully operate such wheelchairs,” states José del R. Millán, the research studys corresponding author at The University of Texas at Austin. “Our research highlights a potential path for enhanced medical translation of non-invasive brain-machine user interface technology.”
Millán and his colleagues recruited 3 tetraplegic individuals for the longitudinal research study. Each of the participants went through training sessions three times per week for 2 to 5 months. The individuals used a skullcap that found their brain activities through electroencephalography (EEG), which would be transformed to mechanical commands for the wheelchairs by means of a brain-machine user interface device. The individuals were asked to manage the instructions of the wheelchair by thinking of moving their body parts. Particularly, they required to believe about moving both hands to turn left and both feet to turn.
The individuals used a skullcap that spotted their brain activities through electroencephalography (EEG), which would be converted to mechanical commands for the wheelchairs through a brain-machine user interface device. The individuals were asked to control the direction of the wheelchair by thinking about moving their body parts. Compared with participants 1 and 3, individual 2 had no substantial changes in brain activity patterns throughout the training. By the end of the training, all participants were asked to drive their wheelchairs across a chaotic healthcare facility space. Both individuals 1 and 3 ended up the task while participant 2 failed to complete it.
This video reveals an individual operating a mind-controlled wheelchair across a chaotic space. Credit: Luca Tonin
In the first training session, 3 individuals had similar levels of precision– when the devices reactions lined up with users thoughts– of around 43% to 55%. Over the course of training, the brain-machine interface device team saw significant enhancement in accuracy in participant 1, who reached a precision of over 95% by the end of his training. The team also observed a boost in accuracy in participant 3 to 98% halfway through his training before the team upgraded his device with a brand-new algorithm.
The enhancement seen in participants 1 and 3 is correlated with enhancement in feature discriminancy, which is the algorithms capability to discriminate the brain activity pattern encoded for “go left” ideas from that for “go right.” The team discovered that the better function discrimnancy is not just a result of artificial intelligence of the gadget however likewise finding out in the brain of the individuals. The EEG of individuals 1 and 3 showed clear shifts in brainwave patterns as they enhanced accuracy in mind-controlling the device.
” We see from the EEG results that the topic has actually combined a skill of regulating different parts of their brains to create a pattern for go left and a different pattern for go right,” Millán says. “We believe there is a cortical reorganization that occurred as a result of the individuals learning procedure.”
Compared to participants 1 and 3, individual 2 had no considerable modifications in brain activity patterns throughout the training. His accuracy increased only somewhat throughout the very first few sessions, which remained steady for the rest of the training duration. It suggests artificial intelligence alone is inadequate for effectively steering such a mind-controlled gadget, Millán says
By the end of the training, all participants were asked to drive their wheelchairs across a chaotic health center space. They had to go around challenges such as a room divider and hospital beds, which are established to replicate the real-world environment. Both participants 1 and 3 ended up the task while individual 2 failed to finish it.
” It seems that for someone to acquire excellent brain-machine interface control that enables them to carry out fairly complicated day-to-day activity like driving the wheelchair in a natural environment, it requires some neuroplastic reorganization in our cortex,” Millán says.
The study likewise emphasized the role of long-lasting training in users. Participant 1 performed incredibly at the end, he had a hard time in the first couple of training sessions as well, Millán states. The longitudinal research study is one of the very first to evaluate the clinical translation of non-invasive brain-machine user interface innovation in tetraplegic people.
Next, the team wishes to find out why participant 2 didnt experience the learning effect. They wish to conduct a more detailed analysis of all individuals brain signals to comprehend their distinctions and possible interventions for individuals having a hard time with the learning process in the future.
Reference: “Learning to control a BMI-driven wheelchair for individuals with extreme tetraplegia” by Tonin and Perdikis et al., 18 November 2022, iScience.DOI: 10.1016/ j.isci.2022.105418.
This work was partially supported by the Italian Minister for Education and by the Department of Information Engineering of the University of Padova.