Scientists are getting closer to something that wouldn’t look out of place in a sci-fi movie: bionic limbs that can sense and transmit touch to their users.
In a new study published this week, researchers have debuted a bionic hand system that can reportedly reproduce the most complex tactile sensations seen to date. Scientists from the Cortical Bionics Research Group have developed a new brain-computer interface (BCI) device, which has been tested on volunteers with spinal cord injuries.
Through a series of experiments, the researchers were able to translate and transmit sensations related to movement, curvature and orientation that allowed volunteers to perform complicated tasks with their bionic limbs. The researchers say their device has now reached a new level of artificial touch.
There were important progress in prosthetic and bionic limb technology in recent years, but these limbs are currently still far from fully approaching the complex nature of human touch. Some scientists have begun to use intracortical microstimulation (ICMS) of the brain’s somatosensory cortex to bridge this gap, as experiments have shown that such stimulation can produce vivid tactile sensations on human skin. However, according to study researcher Giacomo Valle, early attempts with ICMS were mostly focused on reproducing the location and intensity of sensation. But there is much more that goes into feeling something than just those two aspects.
“While point of contact and force are critical feedback components, the sense of touch is far richer than this, also conveying information about texture, material properties, local contours and the movement of objects across the skin. Without these rich sensations, artificial touch will remain very impoverished,” Valle told Gizmodo. In their new study, published Thursday at ScienceValle and his team believe they have taken a crucial step forward with ICMS.
The researchers recruited two people with spinal cord injuries for their experiments. The volunteers first received brain implants in the sensory and motor regions of the brain that control the hands and arms. Using these implants, the researchers recorded and then deciphered the different patterns of electrical activity produced by the volunteers’ brains as they thought about using their paralyzed limbs. The volunteers were then connected to a BCI device that acted as a bionic limb. With just their thoughts, the volunteers could control the limb, which was equipped with sensors that communicated with the brain implants. The researchers were then able to translate and send more complex touch-related sensations through the bionic limb to the volunteers’ brain implants.
“In this work, for the first time, the research went beyond anything previously done in the field of brain-computer interfaces – we conveyed tactile sensations related to orientation, curvature, movement and 3D shapes to the participant using a brain-controlled bionic limb ,” said Valle, a bionics researcher at Chalmers University of Technology. way to encode complex sensations. This allowed for a more vivid sensory feedback and experience while using the bionic arm.”
The volunteers couldn’t just feel more layered sensations like touching the edge of an object—these feelings seem to come from their own hands. The added input also appears to have made it easier for volunteers to more accurately perform complex tasks with bionic limbs, such as moving objects from one place to another. And it’s this richness, Valle said, “that is key to achieving the level of dexterity, manipulation and high-dimensional tactile experience typical of the human hand.”
It’s still early days, the researchers note. More complex sensors and robotic technology, such as prosthetic skin, will be needed to truly capture the sensations that researchers can now encode and transmit to the user, Valle says, and more advanced brain implants will also be needed to increase the range of sensations that can be stimulated. But Valle and his team hope that such progress can be made, and that a bionic limb that actually feels human is quite possible.
“While many challenges remain, this latest study offers evidence that the path to regaining touch is becoming clearer. With each new set of discoveries, we move closer to a future where a prosthetic body part is not just a functional tool, but a way to experience the world,” he said.
The immediate next phase of Valle and his team’s research will be to test their BCI systems in more natural settings, such as patients’ homes. And their ultimate goal is to improve the independence and quality of life of people with disabilities.