Visually impaired man using tactile tiles to navigate city, finishing crossroad
This story is part of a series on the current progression in Regenerative Medicine. This piece discusses advances in brain-machine interfaces.
In 1999, I defined regenerative medicine as the collection of interventions that restore to normal function tissues and organs that have been damaged by disease, injured by trauma, or worn by time. I include a full spectrum of chemical, gene, and protein-based medicines, cell-based therapies, and biomechanical interventions that achieve that goal.
New brain implants allow blind users to see using prosthetic electrodes in their visual cortex. There are roughly 40 million people worldwide who suffer from blindness and an additional 250 million with moderate-to-severe visual impairment. Most blindness is brought about through injury or aging, while others are born with genetic conditions resulting in a lack of sight. While full restoration of eyesight through medical intervention is still impossible, new brain implants may enable significant restoration.
The project, called NeuraViPeR, was started in the EU in late 2020 with the intention of providing an affordable prosthetic vision replacement for more than 2.5 million blind Europeans.
The final product is scheduled for mass availability in 2025, and full detailed studies on the implants are still in the works, but the researchers behind the project have released other data that I will piece together here.
The first human test subject for NeuraViPeR was fitted with a small implant in the brain’s visual processing cortex. In sight-abled people, when light hits the retina, photoreceptors in the eye translate the light to electrical signals interpreted by the brain in the visual cortex. Blindness typically involves the degradation of the retina or the optic nerve that connects the eyes to the brain. An implant to the visual cortex bypasses these damaged regions.
The patient’s implant consisted of just under 100 microelectrodes, which could be activated and seen by the user despite their blindness. The implant was digitally connected to a pair of glasses fitted with a video camera that captured movement and relayed that information to the implant, just as our eyes do for the visual cortex.
The electrodes then activate when the user’s glasses detect movement, resulting in sight for the blind. The following was taken from a preliminary study using the same technology.
FIGURE 1: Image recognition by visual prosthetic using (B) edge-based recognition vs (C) event-based … [+]
The electrodes are capable of detecting the edge of an object as well as the motion. Unfortunately, detailed imagery is difficult, with only 96 electrodes within the implant. Normal human vision has a resolution of one million pixels. As such, detailed vision through an implant with magnitudes fewer electrodes is not yet possible.
The researchers suggest that for a blind person to easily navigate a room or discern a face, the implant would need between 1,000 and 2,000 electrodes.
The transfer of information between the visual processor and brain implant must also speed up. In addition to the image quality being low with only 96 electrodes, the frame rate is also low due to the slow processing of visual data through the implant.
A separate project, HyperStim, began in November 2022 to address processing speed alongside the NeuraViPeR project.
Through an objective lens, the final version of the technology is still years away. The researchers must still create implants containing 10 to 20-fold denser electrode bunches and much faster processing systems for the implants.
However, blindness was once a life sentence, with little to no options in terms of therapy. NeuraViPeR and HyperStim and great steps in the right direction and may yield tangible blindness-inhibiting prosthetics in only a few short years.
To read more of this series, please visit www.williamhaseltine.com
