With VizWiz, the blind can take a picture, ask a question, and get an answer back from a real person in seconds.
What’s the News: With the web as their eyes, the blind will able to read menus, identify canned foods, and tell whether that park has any free benches without having to walk over. That’s the vision of a team of computer scientists behind an iPhone app called VizWiz, which lets people take a photo of whatever’s perplexing them, record a question like “What denomination is this bill?” and send it off to real people online who’ll respond in a matter of seconds with “That’s a 20.”
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What’s the News: Neuroscientists have found a preliminary answer to a question that has puzzled philosophers for centuries: If someone who has always been blind is one day able to see, can they recognize by sight objects they already know by touch? In a new study published online by Nature Neuroscience, patients who had been blind since birth underwent sight-restoring surgeries as children or adolescent. In the day or two following surgery, patients seemed unable to match what they felt with their hands with what they saw, the researchers found, but a week later, they could.
This results suggests that the brain doesn’t have the innate ability (or maybe has limited innate ability) to tie input from different senses to the same concept—but that it can learn, and pretty fast. Just how fast, the researchers wrote, suggests that the neuronal machinery needed to bring together visual and tactile information may already be there; it just has to be started up.
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Embryonic stem cell treatments are edging closer to mainstream medicine. An experimental treatment just approved for clinical trials may provide hope to the 10 to 15 million elderly patients in the United States who suffer from a common form of macular degeneration, which causes gradual blindness.
The biotech company behind the treatment, Advanced Cell Technology, Inc., previously won FDA approval to try an embryonic stem cell treatment on patients with a rare, juvenile form of macular degeneration. The new FDA-approved trial will use similar techniques, but targets a much broader patient base.
“ACT is now the first company to receive FDA clearance for two hESC (human embryonic stem cell) trials, and is now a true translational leader in the field of regenerative medicine,” said chief executive Gary Rabin. “It marks a major step forward, not just within the stem cell sector, but, potentially for modern healthcare techniques.” [AFP]
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Embryonic stem cell treatments are finally breaking out of the lab and arriving in the clinic. In October, the first federally approved trial of a treatment derived from these controversial cells got underway in patients with spinal cord injuries. Now, the FDA has approved a second trial, this one to test a treatment for a rare disease that causes serious vision loss or blindness.
The company behind the trial, Advanced Cell Technology, will test the safety and efficacy of the treatment on 12 patients.
The trial will examine the safety of a therapy for Stargardt’s Macular Degeneration, an inherited juvenile eye disease affecting an estimated 1 in 10,000 young people in the US. As the disease progresses, a layer of the retina called the retinal pigment epithelium (RPE) degenerates, causing vision loss. It’s hoped the new therapy would also work for other types of macular degeneration, a widespread cause of blindness, particularly in the elderly. [Nature blog]
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The winners of the Lasker Awards, the top medical prizes given out in the United States, were announced today.
The Laskers, awarded by the Albert and Mary Lasker Foundation, are $250,000 awards generally regarded as good predictors of who will go on to win a Nobel Prize for medicine or chemistry. [ABC News]
The driver of obesity
Douglas Coleman and Jeffrey Friedman took home the prize in the first category, basic medical research. The pair discovered leptin, a hormone that governs body weight and appetite. Its discovery helped to explain parts of obesity that had never been understood.
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When a person’s cornea is burned it’s not necessarily the splashed chemicals or hot liquids that causes blindness, but the eye’s recovery. Scar tissue, formed from cells in the white part of the eye, can cover the cornea in a cloudy haze. But researchers have found that cells drawn from another part of the body can correct the problem.
A paper published yesterday in the New England Journal of Medicine brings news of a regenerative stem cell treatment that has had striking success: It restored sight to 82 of 117 eyes with burnt corneas, and worked partially on 14 others. The treatment also seems to have a long-lasting impact; in one patient, the beneficial effect has lasted for ten years and counting.
The treatment offers hope to those who received little benefit from existing therapies–such as artificial cornea replacements, which can also be overpowered and clouded by white-colored cells, or stem cell or cornea transplants from cadavers, which patients can reject.
“[The patients] were incredibly happy. Some said it was a miracle,” said one of the study leaders, Graziella Pellegrini of the University of Modena’s Center for Regenerative Medicine in Italy. “It was not a miracle. It was simply a technique.” [AP]
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The weird phenomenon of blindsight—in which people take in visual information about objects without actually “seeing” them—has long intrigued scientists, and with good reason. They’ve watched people navigate obstacle courses and identify colors while being technically blind. This week, in a study in Nature, neuroscientists point to a part of the brain called the lateral geniculate nucleus (LGN) as the neural key that might make blindsight possible.
They used macaques in which the primary visual cortex had been destroyed. The monkeys’ eye-focusing movements revealed that they were “seeing” images shown at the periphery of their visual field, but only if their LGN was intact [New Scientist].
The authors refer to the LGN as the “main relay” between the retina and main visual cortex.
Other work had shown that the LGN also has projections to a number of secondary visual areas, suggesting that it may serve as a major hub in the visual system. To test this suggestion, the authors injected the LGN with a chemical that activates the receptor for a major inhibitory signaling molecule…. When the chemical is present, nerve cells receive a signal telling them to stop signaling, so this this injection has the effect of shutting the LGN down entirely [Ars Technica].
When the scientists shut down the LGN, the primates in the study didn’t experience any blindsight, as it appears no information was reaching any of their brains’ visual centers.
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Image: iStockphoto
For two squirrel monkeys nicknamed Dalton and Sam, life has gotten a lot more colorful. Researchers used gene therapy to correct the color blindness of the two adult monkeys, giving them the ability to distinguish between red and green for the first time. The fascinating accomplishment suggests that scientists may someday be able to cure other kinds of blindness in humans. And because the treated monkeys were “middle aged”, it challenges the assumption that gene therapies cannot work in adults because their brain connections are too set in their ways to change beneficially [New Scientist].
The field of gene therapy, in which a malfunctioning gene in a patient’s body is replaced with a functional one, fell into disarray one decade ago following the death of an 18-year-old in a clinical trial. But since then scientists have regrouped, using animal studies to probe the technique’s safety. Last year, researchers progressed to the point of safety trials in humans for the treatment of one rare eye condition called Leber congenital amaurosis, and were able to dramatically improve the patients’ sight. Those results were stunning, but they were also achieved in children, whose still-growing brains can rewire themselves on the fly in response to new sources of visual stimuli [Wired.com].
In the new study, published in Nature, the researchers used a type of squirrel monkey in which the males lack a visual pigment called L-opsin. Its absence renders the monkeys color-blind, unable to distinguish reds and green. Most of the females, on the other hand, see in full color. So the scientists got to wondering: what would happen if they gave a boy squirrel monkey the same opsin that girls have [Scientific American]. They used a harmless virus to ferry in the gene that makes opsin, injecting the virus behind the monkeys’ retinas.
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Three patients with severe damage to the corneas of their eyes have achieved dramatic improvements in their vision thanks to contact lenses coated with their own stem cells. While the study was extremely small and the results are quite preliminary, the unequivocal improvement seen in the three patients has given doctors hope that the treatment may work for many patients with damaged corneas. Two of the three patients were legally blind in the treated eye; they can now read big letters on the eye chart. The third could read the top few rows of the chart but is now able to pass the vision test for a driving license [The Australian].
The cornea is the transparent layer that covers the eye – but it can lose transparency, damaging sight. In the most serious cases, people can need cornea grafts or transplants. Corneal disease can be caused by genetic disorders, surgery, burns, infections or chemotherapy. In this study, all three patients had damage to the epithelium – the layer of cells covering the front of the cornea [BBC News].
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Stroke patients with damaged vision may be able to restore their sight with the help of computer exercises based on the phenomenon known as blindsight–when a person with vision loss senses something they cannot actually see [Reuters]. Lead researcher Krystel Huxlin explains that people with blindsight may not be able to consciously perceive a visual stimulus, yet when they’re forced to answer questions about it their answers are often correct.
Researchers studied patients whose strokes had damaged their primary visual cortex, and whose impaired vision limits some everyday activities like reading and driving. “This is a type of brain damage that clinicians and scientists have long believed you simply can’t recover from. It’s devastating, and patients are usually sent home to somehow deal with it the best they can” [CBC], says Huxlin. The primary visual cortex is the gateway to the rest of the brain for most of the visual information that comes through the eyes, Huxlin said. That area passes visual information along to dozens of other parts of the brain, which then makes sense of the information, allowing people to see [Bloomberg].
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The facial expressions that register human joy and disappointment may be hard-wired into our brains, according to a new study. To probe the origins of smiles and scowls, psychologist David Matsumoto and his team compared 4,800 photographs, capturing the expressions of sighted and blind judo athletes at medal ceremonies at the 2004 Olympic and Paralympic Games. In each case, the faces of gold and silver medal winning athletes were scrutinised [BBC News].
The researchers found that both the blind and sighted gold medal winners produced joyful smiles known as Duchenne smiles, in which the cheek muscles rise and the muscles around the eyes crease. In contrast, both blind and sighted silver medal winners initially showed sadness, with their mouths turned down, but put on “social smiles” that use only the mouth muscles when they received their medals.
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In a remarkable experiment, researchers found that a man who was rendered completely blind by several strokes could deftly navigate an obstacle course unaided, easily avoiding boxes and sidling around pieces of office equipment. The patient, known only as TN, was left blind after damage to the visual (striate) cortex in both hemispheres of the brain following consecutive strokes. His eyes are normal but his brain cannot process the information they send in, rendering him totally blind [BBC News]. Researchers say TN’s successful performance was an example of the phenomenon “blindsight,” and say it suggests that some small amount of information is being transmitted from his undamaged eyes to a more primitive part of his brain, which operates beneath the level of consciousness.
TN usually walks with a cane, but researcher Beatrice de Gelder convinced him to put it aside and to try to navigate the obstacle course without its help. He was able to do so flawlessly, despite being unable to consciously see any of the obstacles. Head down and hands loose by his side, he twisted his body to slalom slowly but surely between a camera tripod and a swingbin, and neatly stepped around a random series of smaller items. “At first he was nervous,” says de Gelder. “He said he wouldn’t be able to do it because he was blind.” The scientists broke into spontaneous cheers when he succeeded [Nature News].
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In a promising result for gene therapy, researchers have dramatically improved the vision of several patients with a rare, inherited eye condition called Leber congenital amaurosis. The early study was intended to simply test the safety of the treatment, but the patients displayed such significant improvement that researchers decided to publicize the results.
Gene therapy works on a simple principle – to replace a malfunctioning gene, and restore function to a part of the body affected by a genetic disorder. In practice, however, it has proved very difficult to find ways to introduce the new gene copies in the correct tissues, and experiments in animals have had mixed results [BBC News].
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