Now, robot arm that follows thoughts
In a breakthrough, researchers have developed a noninvasive technique that allows people to control a robotic arm using only their thoughts, an advance that may help paralysed people and those with neurodegenerative diseases.
“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,” said Bin He, a University of Minnesota biomedical engineering professor and lead researcher on the study.
“Just by imagining moving their arms, they were able to move the robotic arm,” said He.
The noninvasive technique, called electroencephalography (EEG) based brain-computer interface, records weak electrical activity of the subjects’ brain through a specialised, high-tech EEG cap fitted with 64 electrodes and converts the “thoughts” into action by advanced signal processing and machine learning.
Eight healthy human subjects completed the experimental sessions of the study wearing the EEG cap. Subjects gradually learned to imagine moving their own arms without actually moving them to control a robotic arm in 3D space. Eventually, they were able to move the robotic arm to reach and grasp objects in random locations on a table and move objects from the table to a three-layer shelf by only thinking about these movements.
All eight subjects could control a robotic arm to pick up objects in fixed locations with an average success rate above 80 per cent and move objects from the table onto the shelf with an average success rate above 70 per cent.
“This is exciting as all subjects accomplished the tasks using a completely noninvasive technique. We see a big potential for this research to help people who are paralysed or have neurodegenerative diseases to become more independent without a need for surgical implants,” He said.
The researchers said the brain-computer interface technology works due to the geography of the motor cortex - the area of the cerebrum that governs movement.
When humans move, or think about a movement, neurons in the motor cortex produce tiny electric currents.
Thinking about a different movement activates a new assortment of neurons, a phenomenon confirmed by cross-validation using functional MRI in He’s previous study.