Neuroprosthetic limbs: Leap forward with mind-controlled robotic arm
Successful training and operating a robotic arm employing a brain-computer interface (BCI) is demonstrated in the most comprehensive human clinical study on this issue to date, published online in The Lancet.
A 52-year-old individual with tetraplegia (four limb paralysis) was able to operate a robotic arm with 7 degrees of freedom in the end, accurate enough to perform complex tasks, including feeding herself a bar of chocolate for the first time in 9 years. As a breakthrough in the area of neuroprosthetics, this is the first demonstration of a person with longstanding paralysis to regain their ability to perform complex tasks with the help of brain-computer interfaces.
To achieve this feet, co-investigator and UPMC neurosurgeon Elizabeth Tyler-Kabara, M.D., Ph.D., assistant professor, Department of Neurological Surgery, Pitt School of Medicine, implanted two 96-channel intracortical microelectrodes in the motor cortex of the brain in order to sense neural activity from the electric impulses fired by single neurons. These signals are then processed by computer algorithms to decipher certain patterns translating to intended actions. This method requires a learning process, for both the controlling subject as well as the pattern recognition, which finished considerably faster than expected. After just one week, instead of one month, movements in three directions could be accomplished.
The study cites a total of 13 weeks of brain-machine interface training to gain 7-degree control of the robotic arm, including three-dimensional orientation, 3-D translation and 1-D grasping of the hand, all assessed with clinical measures of upper limb function.
The team of researchers, lead by Jennifer Collinger, Ph.D., assistant professor, Department of Physical Medicine and Rehabilitation (PM&R), and research scientist for the VA Pittsburgh Healthcare System, is providing hope for the many people who are suffering from paralysis and amputated limbs, that they will regain the ability to perform everyday tasks rather sooner than later with the help of more refined neuroprosthetics, for example controlled with wireless electrodes implanted in their brains. It could be even possible to stimulate and control the original muscles in paralyzed limbs in the future, instead of robotic limbs, according to Dr. Collinger.