Patients with prosthetic limbs or spinal cord damage don’t have a sense of touch from their limbs to provide feedback about their position or movements. We’ve written about a number of different research projects working on this problem, and here is another.

Researchers at the University of Washington have been experimenting with direct stimulation of the brain using motion sensors to provide a simulated sense of touch. In their experiments, they found that subjects could rapidly learn to interpret signals during the test, and then moving their hands to the desired position. These “novel” stimuli could interpreted to effectively control motions.

The researchers used epileptic patients in the study. These patients had a grid of electrical sensors implanted on the surface of their brain (as opposed to using electrodes attached to the scalp on the outside of the head). This grid can record electrical activity as well as be used to provide electrical stimulation of the brain. Surgeons use this grid with epileptic patients prior to surgery, in order to map the locations responsible for an individual’s seizures. The researchers enlisted volunteers who were undergoing this procedure, and asked them to be subjects in the study.

The feedback signals in this study were simplistic, and far more complex systems will be required to enable patients to perform normal daily activities, but it’s an encouraging step in the right direction. From powered prosthetic hands to helping paraplegics walk again, the potential to provide a simulated sense of touch holds great promise.