Researchers bring the sense of touch to robotic prosthetics

The human sense of touch is critical to being able to perform many activities of daily living. We take our ability to feel how heavy a cup of hot liquid is and make adjustments without thinking about it to prevent liquid from spilling from the cup. For people who use prosthetic devices, even advanced futuristic mind-controlled prosthetics of the future won't have the normal human sense of touch to rely on. Researchers from the University of Pittsburgh Rehab and Neural Engineering Labs have shown a new method that describes how adding brain stimulation can provide tactile sensations making it easier for operators of a brain-controlled robotic arm to manipulate the prostatic.

Combining supplementing vision only with artificial tactile perception, the team was able to cut the time spent grasping and transferring objects in half from a typical time of 20.9 seconds to 10.2 seconds. Co-senior author of the paper, Jennifer Collinger Ph.D., says that the results of their experiment showed what they hoped would happen, but they didn't expect success to the degree observed.

Collinger says sensory feedback from limbs and hands is vital for performing everyday activities in our daily lives. When that feedback is missing, it has a significant impact on the user's performance. A participant in the study named Nathan Copeland is the first person in the world to be implanted with tiny electrode arrays in the motor cortex of his brain and his somatosensory cortex, which is the portion of the brain that processes sensory information from our body. The implants allow him to control the robotic arm using his mind and perceive tactile sensory feedback from the prosthetic.

Researchers say the paper highlights improvement compared to an earlier study describing how stimulating sensory regions of the brain using electrical pulses can evoke sensation in distinct areas of a person's hand. For the new study, the researchers combined reading the information from the brain to control the movement of the robotic arm along with writing information back to the brain to provide sensory feedback. Collinger and Robert Gaunt, Ph.D., tested the effect of sensory feedback in conditions that closely resemble what would occur in the real world.