Now that the mechanical aspects of prosthetic arms have gotten quite impressive, getting these devices to have a sense of touch is a major next step to overcome. At Washington University in St. Louis, scientists have created a new device that can stimulate nerve cells in the arm and produce sensations that are not really happening.
The macro-sieve device they developed is designed to interface with the ulnar and median nerves in the arm. It’s tiny and flexible, and looks like a wheel with holes drilled through it. The holes allow the nerve to grow through them, linking any potential sensing device to the central nervous system. The researchers will be testing the device on primates to see how well it transmits sensory data and will compare it to the commonly used cuff electrodes. Moreover, they will conduct a study to identify the maximum number of concurrent channels that can be used to transmit signals, which will point to the maximum number of touch and temperature sensors that can be used with the new device.
“If this works to stimulate motor neurons in muscles, we can certainly stimulate sensory neurons, and that’s never been done in a behavioral model in nonhuman primates,” said Daniel Moran, PhD, professor of biomedical engineering at Washington University in St. Louis and lead researcher of this study.
“The more real estate the brain uses, the more processing power and the more important something is,” Moran says. “The hand area in the somatosensory cortex is a big piece of brain, so there should be a lot of bandwidth. We think we’ll be able to send a lot of information to it.”