Very informative case study. On Thu, Oct 28, 2021 at 4:34 PM Minar Singh <[email protected]> wrote:
> Brain Implant Gives Blind Woman Artificial Vision in Scientific First > > https://www.sciencealert.com/a-brain-implant-has-allowed-a-blind-woman-to-see-simple-2d-shapes-and-letters?fbclid=IwAR0IZiWFG71-S2tiyLl4x3SC379iq9yV6f3-XojdCL_169RwgB6Xowkm-vI > CARLY CASSELLA > 28 OCTOBER 2021 > A 'visual prosthesis' implanted directly into the brain has allowed a > blind woman to perceive two-dimensional shapes and letters for the > first time in 16 years. > The US researchers behind this phenomenal advance in optical > prostheses have recently published the results of their experiments, > presenting findings that could help revolutionize the way we help > those without sight see again. > At age 42, Berna Gomez developed toxic optic neuropathy, a deleterious > medical condition that rapidly destroyed the optic nerves connecting > her eyes to her brain. > In just a few days, the faces of Gomez' two children and her husband > had faded into darkness, and her career as a science teacher had come > to an unexpected end. > Then, in 2018, at age 57, Gomez made a brave decision. She volunteered > to be the very first person to have a tiny electrode with a hundred > microneedles implanted into the visual region of her brain. The > prototype would be no larger than a penny, roughly 4 mm by 4 mm, and > it would be taken out again after six months. > Unlike retinal implants, which are being explored as means of > artificially using light to stimulate the nerves leaving the retina, > this particular device, known as the Moran|Cortivis Prosthesis, > bypasses the eye and optic nerve completely and goes straight to the > source of visual perception. > After undergoing neurosurgery to implant the device in Spain, Gomez > spent the next six months going into the lab every day for four hours > to undergo tests and training with the new prosthesis. > The first two months were largely spent getting Gomez to differentiate > between the spontaneous pinpricks of light she still occasionally sees > in her mind, and the spots of light that were induced by direct > stimulation of her prosthesis. > Once she could do this, researchers could start presenting her with > actual visual challenges. > When an electrode in her prosthesis was stimulated, Gomez reported > 'seeing' a prick of light, known as a phosphene. Depending on the > strength of the stimulation, the spot of light could be brighter or > more faded, a white color or more of a sepia tone. > When more than two electrodes were simultaneously stimulated, Gomez > found it easier to perceive the spots of light. Some stimulation > patterns looked like closely spaced dots, while others were more like > horizontal lines. > "I can see something!" Gomez exclaimed upon glimpsing a white line in > her brain in 2018. > Vertical lines were the hardest for researchers to induce, but by the > end of training Gomez was able to correctly discriminate between > horizontal and vertical patterns with an accuracy of 100 percent. > The Utah Electrode Array in actionThe Utah Electrode Array in action. > (John A. Moran Eye Center at the University of Utah) > "Furthermore, the subject reported that the percepts had more > elongated shapes when we increased the distance between the > stimulating electrodes," the authors write in their paper. > "This suggests that the phosphene's size and appearance is not only a > function of the number of electrodes being stimulated, but also of > their spatial distribution… " > Given these promising results, the very last month of the experiment > was used to investigate whether Gomez could 'see' letters with her > prosthesis. > When up to 16 electrodes were simultaneously stimulated in different > patterns, Gomez could reliably identify some letters like I, L, C, V > and O. She could even differentiate between an uppercase O and a > lowercase o. > The patterns of stimulation needed for the rest of the alphabet are > still unknown, but the findings suggest the way we stimulate neurons > with electrodes in the brain can create two-dimensional images. > The last part of the experiment involved Gomez wearing special glasses > that were embedded with a miniature video camera. This camera scanned > objects in front of her and then stimulated different combinations of > electrodes in her brain via the prosthesis, thereby creating simple > visual images. > The glasses ultimately allowed Gomez to discriminate between the > contrasting borders of black and white bars on cardboard. She could > even find the location of a large white square on either the left or > right half of a computer screen. The more Gomez practiced, the faster > she got. > The results are encouraging, but they only exist for a single subject > over the course of six months. Before this prototype becomes available > for clinical use it will need to be tested among many more patients > for much longer periods of time. > Other studies have implanted the same microelectrode arrays, known as > Utah Electrode Arrays, into other parts of the brain to help control > artificial limbs, so we know they're safe in at least the short term. > But it's still early days for the tech, which risks a steady drop in > functionality over just a few months of operation. > While engineers beef up the reliability of the devices, we still need > to know exactly how to program the software that interprets the visual > input. > Last year, researchers at Baylor College of Medicine in Houston > inserted a similar device into a deeper part of the visual cortex. > Among five study participants, three of whom were sighted and two of > whom were blind, the team found the device helped blind people trace > the shapes of simple letters like W, S, and Z. > In Gomez's case, there was no evidence of the device triggering neural > death, epileptic seizures, or other negative side effects, which is a > good sign, and suggests microstimulation can be safely used to restore > functional vision, even among those who have suffered irreversible > damage to their retinas or optic nerves. > "One goal of this research is to give a blind person more mobility," > says bioengineer Richard Normann from the University of Utah. > "It could allow them to identify a person, doorways, or cars easily. > It could increase independence and safety. That's what we're working > toward." > Right now, it seems only a very rudimentary form of sight can be > returned with visual prostheses, but the more we study the brain and > these devices among blind and sighted people, the better we will get > at figuring out how certain patterns of stimulation can reproduce more > complex visual images. > Perhaps one day, other patients in the future will be able to trace > the whole alphabet with this prosthesis because of what Gomez has > done. Four more patients are already lined up to try out the device. > "I know I am blind, that I will always be blind," Gomez said in a > statement a few years ago. > "But I felt like I could do something to help people in the future. I > still feel that way." > Gomez's name is listed as co-author on the paper for all her insight > and hard work. > The study was published in the Journal of Clinical Investigation. > > -- > Disclaimer: > 1. 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