- A group of researchers has sought to use a microelectrode array to aid in the perception of letters and shapes by a blind person.
- The implant, which is roughly the size of a cent, works by stimulating the brain’s visual cortex rather than the optic nerve.
- The subject was able to recognize many letters at the conclusion of the research.
According to the Centers for Disease Control and Prevention (CDC), around 1 million adults over the age of 40 are blind in the United States.
Although there is presently no cure for blindness, a novel implanted technology might one day help blind individuals gain more freedom. An electrode is used to produce artificial eyesight with the implant.
Despite the fact that the technology is still in its early phases of clinical development, the first human trial proved successful. The findings have been published in The Journal of Clinical Investigation.
Researchers from Spain partnered with academics from the Netherlands Institute for Neuroscience in Amsterdam and the University of Utah in Salt Lake City on the study by researchers.
Phosphenes
A condition known as spontaneous phosphenes affects blind people. When blind persons experience random flashes of light without any light entering the eye, they are seeing phosphones.
People who are blind can also get phosphenes. When a person touches their eye, for example, pressure phosphenes form. Phosphenes can also be triggered by some medicines, ionizing radiation, and electrical and magnetic stimulation.
Despite the fact that spontaneous phosphenes do not give functional vision, their manipulation was crucial in the latest research.
Brain implant
The Utah electrode array (UAE) was implanted directly into the visual cortex of the participant’s brain for this investigation. The visual cortex is in charge of processing visual data. The UAE was made up of 96 microelectrodes that protruded from a silicon base.
“A long-held dream of scientists is to transfer information directly to the visual cortex of blind individuals, thereby restoring a rudimentary form of sight,” write the authors. “However, there is currently no clinically viable cortical visual prosthesis.”
The trial lasted six months and only had one participant: a 57-year-old lady who had gone blind 16 years before the study began.
The person had a few weeks to heal after the scientists inserted the gadget. Before the researchers could begin testing the gadget, they needed to demonstrate that the subject could distinguish between spontaneous phosphenes and the phosphenes that the team sought to create as part of giving functional vision.
The researchers began training and presenting her with genuine visual problems after determining that the subject could recognize the produced phosphenes with 95% accuracy.
Training sessions were held five days a week, once or twice a day, and lasted up to four hours each. This went on for six months. The researchers used a pair of customized spectacles to connect to the implant and track the participant’s eye movements.
The subject improved her ability to recognize phosphenes in a specific location during the course of the trial.
The researchers discovered that stimulating more than two electrodes at the same time made it simpler for the participant to notice the light spots. The outcomes of letter and shape identification were also enhanced by spacing out the stimulating electrodes.
The authors explain, “This shows that the size and appearance of the phosphene is not just a consequence of the number of electrodes being stimulated, but also of their spatial distribution.”
The individual was able to recognize various letters and discern the difference between uppercase and lowercase letters towards the conclusion of the trial, when the team concurrently stimulated up to 16 electrodes in varied patterns.
Dr. Eduardo Fernández, the study’s lead author, spoke with Medical News Today about the findings.
“I would like to emphasize that although our preliminary results are very encouraging, we should be aware that this is still research and not yet a clinical treatment,” said Dr. Fernández.
“In this context, the scientific and technological issues connected with safe and effective brain communication are extremely complicated, and many issues must be resolved before a cortical visual neuroprosthesis can be regarded a viable therapeutic therapy or choice.”
Dr. Fernández is the chairman of the Department of Histology and Anatomy at the University Miguel Hernández (UMH) in Alicante, Spain. He is a professor of cellular biology. He is also the director of the Bioengineering Institute’s Neuroengineering and Neuroprosthesis Unit.
Implications of study
The goal of the implant is to deliver a degree of functional vision rather than complete visual restoration.
“One goal of this research is to give a blind person more mobility,” says senior study author Dr. Richard Normann, a bioengineer 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,” said Dr. Normann.
Dr. Fernández focused on the implant’s attempt to offer functional vision.
“We are not trying to provide [full vision], that right now is not feasible, but just to provide […] useful vision, for tasks such as orientation, mobility, reading big characters, etc.,” said Dr. Fernández.
“We have to go step by step and […] not create false expectations or underrate the challenges that still remain to be resolved,” Dr. Fernández continued. “In this framework, we propose that increased collaborations among clinicians, basic researchers, engineers, and associations of blind [people] [are] key to advance in this field.”
The brain implant was discussed with MNT by John Nosta, the founder of NostaLab and a member of the World Health Organization’s (WHO) Digital Health Roster of Experts. He stated, “
“[This is] certainly an important step forward that builds upon the existing brain interface technologies, like the cochlear implant and deep brain stimulation for movement disorders.”
Interest-based conflict
It’s worth noting that Pieter R. Roelfsema and Xing Chen, two of the study’s authors, are co-founders and shareholders in Phosphoenix, a neurotechnology start-up.
