Advanced brain interfacing technology for both touch and vision restoration

Patients with untreatable conditions such as sight loss or loss of motor-function could be closer to a viable technology for restoring their lost sense, within a faster time frame. This is due to the discovery that advanced brain interfacing technology used for both touch and vision prostheses, is in fact almost the same, despite being developed completely separately for more than 50 years. The comprehensive review in which this discovery has first been made, was published in Nature Reviews Bioengineering, and was led by Giacomo Valle, Assistant Professor at Chalmers University of Technology, in Sweden.

Despite being developed separately, brain-computer interfaces or BCIs are an emerging field of technology that are being used for restoring more than one lost sense in the body, with visual cortical prostheses (VCP) for vision, and somatosensory cortical prostheses (SCP) for touch.

BCIs work by implanting a microelectrode directly into the brain, to enable direct communication between the brain and external devices (such as a camera or a bionic hand). They can bypass the damaged pathways in the body by directly stimulating a specific region of the brain and mimicking a natural sensation in a patient.

This technology presents a real step forward for patients with otherwise untreatable conditions, in both the fields of sight-loss and loss of motor-function (such as paralysis), giving the ability to control movements, communicate or regain tactile sensation or vision, which previously was not possible."

Giacomo Valle, Assistant Professor, Chalmers University of Technology

One technology, two separate senses

Natural vision and touch have common neural and computational principles in the body; whereby complex information is gathered from the outside world (via the eye or the skin/ hand) and converted into an electrical signal for the brain. Both fields of research have therefore been able to use similar technology to replicate these sensations artificially, with the BCIs placed in different regions of the brain. Yet neither field has spoken to each other until now.

"Normally people work on artificial touch or artificial vision. Researchers go to different conferences and deal with very different conditions and different patients, in different areas of the hospital. There has been parallel development for both senses, but we never talked about this on a global level. Until now, we hadn't seen this as a common challenge", says Valle.

The inspiration behind the review

The review paper 'Restoring vision and touch with cortical microstimulation' compares visual and sensory prostheses side by side for the first time and discusses how the two fields of research can learn from each other. It looks into how electrical stimulation of the cerebral cortex works, the types of electrodes used, how artificial visual and tactile experiences are created, the results of clinical trials to date and what technical and clinical barriers remain.

"The idea of merging the two fields of research came from the last paper that I worked on. We were going beyond restoring a simple sense of touch, moving to more complex sensations. We had to consider how to restore the sense of an edge or tactile motion. And through research, I found that the field of artificial vision was looking at the same challenge, aiming for a more complex artificial vision," says Valle.

He points out that in the past, sight-loss and paralysis have been two very different fields of research, with unique challenges and different approaches to solving how to restore these in the body. But with the ongoing and rapid development of technology, these two fields have reached a coalescence.

"Hopefully our paper opens doors for a beneficial collaboration between the two fields and brings us closer to one technology for both artificial vision and touch that would benefit both patient groups. I have a dream for the future that there is one department in the hospital where a patient can go for 'sense restoration' and our unified technology would be easily accessible for all," says Valle.