Most people without disabilities take their ability to perform simple everyday tasks for granted. For example, when they reach for a warm cup of coffee, they can feel its weight and temperature and adjust their grip accordingly so no liquid is spilled. People with full sensation and control over arm and hand movement can know they’ve come into contact with an object as soon as they touch or hold it, allowing them to begin moving or lift it up confidently.
But those tasks become much more difficult when one person operates a prosthetic arm—One person alone controls the mind.
In a paper published in Science, a team of bioengineers from University of Pittsburgh Rehab . Neuroengineering Laboratory describes how adding brain stimulation to evoke tactile sensations makes it easier for operators to control the brain-controlled robotic arm. In testing, supplementing vision with artificial tactile perception cut the time to grasp and transfer objects in half, from an average time of 20.9 to 10.2 seconds.
“In a sense, this is what we hoped would happen — but perhaps not to the extent we had observed,” said co-senior author Jennifer Collinger, an associate professor in Pitt’s Department of Physiotherapy and Rehabilitation. “Sensory feedback from the limbs and hands is vital to performing normal things in our daily lives, and without that feedback, human performance is impaired.”
Study participant Nathan Copeland, who is described in the paper, is the first person in the world to have microscopic electrode arrays implanted not only in the motor cortex but also in the somatosensory cortex – an area of the brain that processes the brain. process sensory information from the body. The array allows him to control the robotic arm with his mind as well as receive haptic feedback with touch, similar to how neural circuits work when a person’s spinal cord is intact.
“I am extremely familiar with both the sensation produced by the stimulus and performing the task without the stimulus. While that feeling isn’t ‘natural’ – it’s more like pressure and a slight tingling sensation – it has never bothered me,” says Copeland. Love is something that I have to get used to. Being on duty and receiving stimulation goes hand in hand like PB&J.”
After a car accident caused him to have limited use of his arm, Copeland enrolled in Clinical trials test the sensor microelectrode brain-computer interface (BCI) and implanted with four microelectrode arrays developed by Blackrock Microsystems (also known as the Utah array).
This paper is a step up from an earlier study that first described how to stimulate sensory areas of the brain using tiny electrical impulses that can evoke sensations in separate areas of a person’s hand, although they lost sensation in their limbs due to spinal cord injury. In this new study, researchers combined reading information from the brain to control the movements of the robotic arm with recording information to provide sensory feedback.
In a series of tests, in which BCI operators were asked to pick up and transfer various objects from a table onto a raised platform, providing haptic feedback via electrical stimulation enabled participants to complete the task. twice as fast as the no-stimulation tests.
In the new paper, the researchers wanted to test the effects of sensory feedback under conditions that resemble the real world as much as possible.
“We didn’t want to limit the task by removing the visual component of perception,” said senior co-author Robert Gaunt, associate professor in the Department of Physical Medicine and Rehabilitation. “When even limited and imperfect feelings are restored, the person’s performance improves in a rather significant way. We’re still a long way from making sensations more realistic and bringing this technology to people’s homes, but the closer we get to recreating normal inputs to the brain, I will become better. ”
Source: University of Pittsburgh
