Lizzie Buchen A once-promising clinical therapy for Huntington's disease needs to head back to the lab, research suggests. Huntington's disease is an inherited, untreatable and fatal disease in which patients develop severe movement and cognitive problems. One approach to treating the disease that picked up steam in the 1990s was the transplantation of healthy neural tissue from the fetuses of women who had undergone elective abortions into the patient's striatum — the brain region most severely affected in the disease. Now the results of the first long-term clinical follow-up of this approach are in1, and they don't bode well. Neurosurgeon Thomas Freeman of the University of South Florida in Tampa and his colleagues have analysed the brains of three people with Huntington's disease who received fetal striatal-tissue transplants a decade before they died. But instead of slowing or stopping the progress of the disease, the grafts degenerated even more severely than the patients' own tissue. "Based on our earlier results we were expecting that the grafts would endure," says Freeman. "This tells us we'll have to do a lot of work in the laboratory before going back to the clinic." © 2009 Nature Publishing Group,

Keyword: Huntingtons
Link ID: 13079 - Posted: 06.24.2010

With 3- and 5-year-old daughters in the house, Dr. Atul Malhotra, 40, knows what it’s like to go without sleep. And as medical director of Brigham and Women’s Hospital’s sleep disorders research program, he gets an earful about sleep problems at work. Malhotra diagnoses and studies patients with disorders including insomnia and sleep apnea, which causes a person to briefly and frequently stop breathing while they sleep. The dangers of undiagnosed sleep apnea were highlighted last week when investigators said the operator of a Green Line train that crashed into another train, killing her, might have suffered from the disorder and fallen asleep for several seconds. Malhotra spoke to reporter Liz Kowalczyk about sleep disorders and how to treat them. Here is an edited version of their conversation. Q. How many people have sleep disorders? A. Four percent of American men and 2 percent of American women have sleep apnea, based on a study published in 1993. But obesity has gotten a lot worse since 1993 and obesity is a major risk factor. Insomnia is also a very common sleep problem. After Sept. 11, no one slept well the next day. People who have chronic insomnia where it’s a sustained problem, that’s 5 to 10 percent of the population. Q. Is chronic insomnia dangerous? A. The short answer is that several studies, including our own, suggest that short sleep is deleterious to your health. If you sleep five hours per night, your risk of heart attack, diabetes, obesity, and mortality are all increased compared with someone who sleeps seven to eight hours a night. © Copyright 2009 Globe Newspaper Company.

Keyword: Sleep
Link ID: 13078 - Posted: 06.24.2010

By SANDRA BLAKESLEE Learning to move a computer cursor or robotic arm with nothing but thoughts can be no different from learning how to play tennis or ride a bicycle, according to a new study of how brains and machines interact. The research, which was carried out in monkeys but is expected to apply to humans, involves a fundamental redesign of brain-machine experiments. In previous studies, the computer interfaces that translate thoughts into movements are given a new set of instructions each day — akin to waking up each morning with a new arm that you have to figure out how to use all over again. In the new experiments, monkeys learned how to move a computer cursor with their thoughts using just one set of instructions and an unusually small number of brain cells that deliver instructions for performing movements the same way each day. “This is the first demonstration that the brain can form a motor memory to control a disembodied device in a way that mirrors how it controls its own body,” said Jose M. Carmena, an assistant professor of computer and cognitive science at the University of California, Berkeley, who led the research. The experiments were described Monday in the journal PloS Biology. The results are very “dramatic and surprising,” said Eberhard E. Fetz, an expert in brain-machine-interface technology at the University of Washington, who was not involved in the research. “It goes to show the brain is smarter than we thought.” Copyright 2009 The New York Times Company

Keyword: Robotics
Link ID: 13077 - Posted: 06.24.2010

By Lindsey Tanner CHICAGO - Researchers for the first time have linked air pollution exposure before birth with lower IQ scores in childhood, bolstering evidence that smog may harm the developing brain. The results are in a study of 249 children of New York City women who wore backpack air monitors for 48 hours during the last few months of pregnancy. They lived in mostly low-income neighborhoods in northern Manhattan and the South Bronx. They had varying levels of exposure to typical kinds of urban air pollution, mostly from car, bus, and truck exhaust. At age 5, before starting school, the children were given IQ tests. Those exposed to the most pollution before birth scored on average four to five points lower than children with less exposure. That’s a big enough difference that it could affect children’s performance in school, said Frederica Perera, the study’s lead author and director of the Columbia Center for Children’s Environmental Health. Dr. Michael Msall, a University of Chicago pediatrician not involved in the research, said the study doesn’t mean that children living in congested cities “aren’t going to learn to read and write and spell.’’ But it does suggest that you don’t have to live right next door to a belching factory to face pollution health risks, and that there may be more dangers from typical urban air pollution than previously thought, he said. © Copyright 2009 Globe Newspaper Company.

Keyword: Development of the Brain; Neurotoxins
Link ID: 13076 - Posted: 06.24.2010

by Ewen Callaway A 10-year old girl born with half of her cerebral cortex missing sees perfectly because of a massive reorganisation of the brain circuits involved in vision, a new study finds. "It was quite a surprise to see that something like this is possible," says Lars Muckli, a neuroscientist at the University of Glasgow, UK, who was part of the team that imaged the girl's brain. Doctors discovered that she was missing the right half at the age of three, after she began suffering from seizures. Normal life However, the seizures proved treatable and the girl – known as AH – lives an otherwise normal life. The left side of her body is slightly weaker than the right, but this hasn't stopped her from bicycling or roller-skating. But what's most amazing, Muckli says, is her ability to see out of the left and right visual fields. Patients who have half of their cortex removed to treat epilepsy invariably lose half of their visual field. "They would only see half of the world; this is what's expected," he says. That's because, each eye sends visual signals to two different halves of the brain via two distinct bundles of nerves. The nerves on the side of the eye nearest the nose are routed to the opposite side of the brain. The nerves nearest the temple, however, send information to the same side of the brain as the eye. © Copyright Reed Business Information Ltd.

Keyword: Vision; Development of the Brain
Link ID: 13075 - Posted: 06.24.2010

By Ibby Caputo After Marine Cpl. Mike Jernigan was blinded by a roadside bomb in Iraq, he said, not much was done for him. "I returned back from Iraq and [Veterans Affairs] gave me a stick. A stick and a tap on the butt and they said, 'Go ahead.' " Five years later and thanks to the ambitions of a handful of people, Jernigan has more than a walking cane. He has been given a special "lollipop," a device that uses his tongue to stimulate his visual cortex and send sensory information to his brain. Also called the intra-oral device, or IOD, the lollipop is an inch-square grid with 625 small round metal pieces. It is connected by a wire to a small camera mounted on a pair of sunglasses and to a hand-held controller about the size of a BlackBerry. The camera sends an image to the lollipop, which transmits a low-voltage pulse to Jernigan's tongue. With training, Jernigan has learned to translate that pulse into pictures. He can now identify the shapes of what is in front of him, even though both of his eyes have been removed. "It's kind of like Braille that you use with your fingers," said Amy Nau, an optometrist who is researching the effectiveness of the device at the University of Pittsburgh. "Instead of symbols, it's a picture, and instead of your fingertips, it's your tongue." The machine is called the BrainPort vision device and is manufactured by Wicab, a biomedical engineering company based in Middleton, Wis. It relies on sensory substitution, the process in which if one sense is damaged, the part of the brain that would normally control that sense can learn to perform another function. In Jernigan's case, the visual cortex is recruited to take on tactile recognition. © 2009 The Washington Post Company

Keyword: Vision; Robotics
Link ID: 13074 - Posted: 06.24.2010

By Nicole Branan Close but no cigar, the saying goes. But new research shows that when it comes to gambling, the human brain seems to take a very different approach. In our head, near misses, such as a lottery ticket just one number away from the jackpot, are interpreted as wins. Using functional MRI, Luke Clark of the University of Cambridge and his colleagues looked at the brains of 15 volunteers who were playing a computerized slot machine. Unsurpri­singly, wins activated the players’ reward system, whereas complete misses did not. When the wheel stopped just one position from the pay line, however, the reward system of volunteers’ brains got excited the same way it did after a win—there was much activity in the striatum and the insula, areas involved in reinforcing behavior with positive feedback. This type of reinforcement makes sense in behaviors that involve actual skill, such as target shooting, because a sense of reward provides encouragement to keep practicing, Clark says. “A near miss in a game of chance doesn’t mean that you are getting better,” he notes, yet it seems that the brain mistakenly activates the same type of reinforcement learning system in these situations. The findings expose the underpinnings of gambling addiction, according to Clark. Even though all volunteers were nongamblers, those whose brain showed a greater response in the scanner also reported feeling more desire to continue trying after near misses. Excessive recruitment of these reward areas, therefore, may be a risk factor for compulsive gambling, Clark says. © 1996-2009 Scientific American Inc

Keyword: Drug Abuse
Link ID: 13073 - Posted: 06.24.2010

By NATALIE ANGIER Certain things should never be taken for granted, among them your spouse, your mother, the United States Constitution, and the precise meaning of words that are at the heart of your profession. Daniel Levitis was working as a teaching assistant for an animal behavior course at the University of California in Berkeley, and on the first day of class, the professor explained that the shorthand definition of a “behavior” is “what animals do.” O.K., that’s the freshman-friendly definition, Mr. Levitis thought. Now how about the unabridged, professional version? What is the point-by-point definition of a behavior that behavioral biologists use when judging whether a particular facet of the natural world falls under their purview? After all, animals digest food and grow fur, yet few behavioral researchers would count such physiological and anatomical doings as behaviors. Mr. Levitis asked the professor for the full definition of a behavior. She referred him to their textbook, with its promising title, “Animal Behavior.” To his surprise, neither that textbook nor any other reference he consulted bothered to spell it out. “It was assumed that everyone knew what the word meant,” said Mr. Levitis, who is completing his doctorate at Berkeley. Mr. Levitis decided to ask the people who should know best: working behavioral biologists. The provocative and crisply written results of his quest, carried out with his colleagues, William Lidicker Jr. and Glenn Freund, appear in the current issue of the journal Animal Behaviour. Among the highlights of the report: biologists don’t agree with one another on what a behavior is; biologists don’t agree with themselves on what a behavior is; biologists can be as parochial as the rest of us, meaning that animal behaviorists tend to reflexively claim the behavior label for animals only, while botanists sniff that, if the well-timed unfurling of a smelly, colorful blossom for the sake of throwing your seed around isn’t the ultimate example of a behavior, then there’s no such thing as Valentine’s Day; and, finally, words may count, but thoughts do not. Copyright 2009 The New York Times Company

Keyword: Miscellaneous
Link ID: 13072 - Posted: 06.24.2010

If you regularly suffer from migraine pain (especially if you develop auras, which are visual or sensory phenomena that accompany the headache), your doctor has probably warned you about your susceptibility to heart attack or stroke. Now, thanks to findings announced in 2007, experts better understand which cardiac ailment is more likely to occur for any given migraine sufferer. Frequency matters. If you have fewer than one migraine a month, you're 50 percent more likely to have a heart attack than nonsufferers. If migraines strike at least weekly, you have three times the risk of stroke, compared with those who don't have this problem, says study co-author Tobias Kurth, MD, an assistant professor at Harvard Medical School. Protect yourself: Unfortunately, existing research has not yet found that preventing migraines has the effect of lowering stroke or heart attack odds. However, by keeping your cardiovascular system as healthy as possible, you diminish your chance of a cardiac event, according to the National Stroke Association. To do this, control known hazards, such as high cholesterol and obesity, via diet and exercise. You should also quit smoking and limit alcohol intake (no more than one drink a day for women, according to the American Heart Association). © 2009 Rodale Inc.

Keyword: Pain & Touch
Link ID: 13071 - Posted: 06.24.2010

Scientists have found a way to block the genetic flaw that causes the most common form of muscular dystrophy. Tests on mice found injecting them with a compound that neutralises the faulty gene's activity led to muscle cells working more effectively. The US team's work, published in Science, could be a step towards treatments to reverse the symptoms of the disease. UK experts said the study results were "exciting". Around 7,500 children and adults in the UK have some form of muscular dystrophy. Myotonic dystrophy, like other forms of the condition, causes muscle weakness and wasting that is usually progressive. It typically affects muscles in the face, jaw and neck. Another symptom is muscle stiffness - myotonia - which tends to be seen in the hands. The condition can appear at any age, and currently there is no treatment that can halt its progress. It is caused by a mutation of a specific gene on chromosome 19. Scientists discovered RNA - which takes genetic messages from the nucleus to the rest of the cell in order to build proteins - was key to myotonic dystrophy. Each gene produces its own RNA. But in myotonic dystrophy, the genetic defect leads to production of a toxic RNA which blocks certain proteins from carrying out their normal functions by sticking to them like Velcro. In this study scientists from the University of Rochester in New York found the blocking of a protein called "muscleblind" causes the characteristic hand stiffness. The toxic RNA accumulates as deposits which are visible in the cell's nucleus. The team used a synthetic molecule, called an antisense morpholino oligonucleotide, that mimics a segment of the genetic code to break up these deposits and re-establish cellular activity. It was specifically designed to bind to the toxic RNA and neutralise its harmful effects. When it was injected into the muscle cells of mice with myotonic dystrophy, the stuck proteins were released and resumed their normal function. The abnormal electrical (myotonic) activity went away. (C)BBC

Keyword: Muscles; Movement Disorders
Link ID: 13070 - Posted: 07.20.2009

By John Cloud For the better part of the past half-century, feminists, their opponents and armies of academics have debated the differences between men and women. Only in the past few years have scientists been able to use imaging technology to look inside men's and women's heads to investigate whether those stereotypical gender differences have roots in the brain. No concrete results have emerged from these studies yet, but now a new functional magnetic resonance imaging (fMRI) study of children offers at least one explanation for some common tween social behaviors: girls are hardwired to care about one-on-one relationships with their BFFs (best friends forever), while the brains of boys are more attuned to group dynamics and competition with other boys. (See the top 10 medical breakthroughs of 2008.) The study, conducted by researchers at the National Institute of Mental Health (NIMH) and Georgia State University, begins with a premise that every parent of a tween knows: as kids emerge into puberty, their focus changes dramatically. They care less about their families and more about their peers. So what's actually going on inside these young brains? Scientists asked 34 healthy kids, ages 8 to 17, to look at pictures of 40 other boys and girls and judge how much they would like to interact with them online. The kids were asked to rate those in the photos on a scale from 0 ("not interested at all") to 100 ("very interested"). The NIMH scientists told the kids that their ratings would be revealed to the boys and girls in the pictures, and the scientists said they would arrange online chats between the kids and those they liked. The chats were supposed to occur two weeks later. (Read "The Myth of the Math Gender Gap.") © 2009 Time Inc

Keyword: Sexual Behavior; Emotions
Link ID: 13069 - Posted: 06.24.2010

By GRETCHEN REYNOLDS Recently, researchers in England discovered that simply rinsing your mouth with a sports drink may fight fatigue. In the experiment, which was published online in February in the Journal of Physiology, eight well-trained cyclists completed a strenuous, all-out time trial on stationary bicycles in a lab. The riders were hooked up to machines that measured their heart rate and power output. Throughout the ride, the cyclists swished various liquids in their mouths but did not swallow. Some of the drinks contained carbohydrates, the primary fuel used during exercise. The other drinks were just flavored, sugar-free water. By the end of the time trials, the cyclists who had rinsed with the carbohydrate drinks — and spit them out — finished significantly faster than the water group. Their heart rates and power output were also higher. But when rating the difficulty of the ride, on a numerical scale, their feelings about the effort involved matched those for the water group. In a separate portion of the experiment, the scientists, using a functional M.R.I., found that areas within the brain that are associated with reward, motivation and emotion were activated when subjects swished a carbohydrate drink. It seems that the brains of the riders getting the carboyhydrate-containing drinks sensed that the riders were about to get more fuel (in the form of calories), which appears to have allowed their muscles to work harder even though they never swallowed the liquid. The role of the brain in determining how far and hard we can exercise — its role, in other words, in fatigue — is contentious. Until recently, most researchers would have said that the brain played littlerole in determining how hard we can exercise. Muscles failed, physiologists thought, because of biochemical reactions within the muscles themselves. They began getting too little oxygen or were doused with too much lactic acid or calcium. They stiffened and seized. Copyright 2009 The New York Times Company

Keyword: Muscles; Emotions
Link ID: 13068 - Posted: 06.24.2010

By Katherine Harmon People with Asperger's syndrome, a variety of autism spectrum disorder, characteristically have trouble perceiving the mental states of others, making social interactions difficult. But many adults with the disorder lead highly functional lives, leaving researchers to wonder how their brains differ from those of neurologically normal adults and children. A report published online yesterday in Science shows that many adults with Asperger's who cannot spontaneously anticipate another person’s state of mind, can still correctly guess it when given a simple verbal prompt to. To test the ability of adults with Asperger's to read another person’s state of mind, the study authors used a test often given to children called the Sally-Anne False Belief Test. In the experiment, subjects watch as an actor places an object in a box and then leaves the room. While the first actor is gone, another actor moves the object to a different location in the room. When the first actor returns to the room, the researchers track the eye movements of the subjects, which indicate where they think the first actor will look for the object. Research has shown that normally developing children as young as two years old correctly expect the first actor to look in the box in which he or she placed the object—not in the spot to which the second actor moved it—thereby imagining the world from someone else’s point of view. © 1996-2009 Scientific American Inc

Keyword: Autism
Link ID: 13067 - Posted: 06.24.2010

by Ewen Callaway We're all familiar with the stereotype of the tortured artist. Salvador Dali's various disorders and Sylvia Plath's depression spring to mind. Now new research seems to show why: a genetic mutation linked to psychosis and schizophrenia also influences creativity. The finding could help to explain why mutations that increase a person's risk of developing mental illnesses such as schizophrenia and bipolar syndrome have been preserved, even preferred, during human evolution, says Szabolcs Kéri, a researcher at Semmelweis University in Budapest, Hungary, who carried out the study. Kéri examined a gene involved in brain development called neuregulin 1, which previous studies have linked to a slightly increased risk of schizophrenia. Moreover, a single DNA letter mutation that affects how much of the neuregulin 1 protein is made in the brain has been linked to psychosis, poor memory and sensitivity to criticism. About 50 per cent of healthy Europeans have one copy of this mutation, while 15 per cent possess two copies. To determine how these variations affect creativity, Kéri genotyped 200 adults who responded to adverts seeking creative and accomplished volunteers. He also gave the volunteers two tests of creative thinking, and devised an objective score of their creative achievements, such as filing a patent or writing a book. © Copyright Reed Business Information Ltd

Keyword: Schizophrenia; Genes & Behavior
Link ID: 13066 - Posted: 06.24.2010

By Michael Price A hungry bat screeches out ultrasonic waves and listens as they echo off surrounding objects. One of those echoes sounds an awful lot like a tasty moth, so it swoops in for the kill--but grabs only air. Thwarted again by the tiger moth Bertholdia trigona. New research explains the clever defense; the moth emits ultrasonic clicks that throw off bats' sonarlike echolocation, like jamming a radio signal. It's the first time this type of acoustic interference has been demonstrated in the natural world. For about 40 years, researchers have been intrigued by the clicking tiger moth, which ranges from Central America to Colorado. Lots of moths click by vibrating membranes on their abdomens, but B. trigona is an order of magnitude louder. "You can hold them up to your ear and hear them," says the study's co-author, biologist William Conner of Wake Forest University in Winston-Salem, North Carolina. Researchers have noticed that clicking moths were eaten less often than their quieter cousins, but how the rapid, high-pitched zzt-zzt-zzt wards off bats has been a mystery. Three possible explanations have emerged. One is that the clicks startle the bats. If that were the case, though, you'd expect bats to learn to ignore the sound, Conner says. Another hypothesis is that the clicks serve as a warning, letting bats know the moth is distasteful. That's thought to be the case with some toxic moths, such as the related dogbane tiger moth, Cycnia tenera; and other nontoxic moths might mimic the technique. Finally, the moths may somehow jam the bats' echolocation, because the clicks occur in the same frequency range as the ultrasound used by the bats. © 2009 American Association for the Advancement of Science.

Keyword: Hearing
Link ID: 13065 - Posted: 06.24.2010

By Susan Gaidos It started as a quiet dinner conversation, punctuated with laughter. Soon, the rapid-fire “ha-ha-has” took on the tone of gunfire. Convinced it was directed at him, the young man got up to confront the noisy diners. Naturally, the guests at the next table had no idea what the problem was. They were simply enjoying themselves and … laughing. Embarrassed by his outburst, the young man left the restaurant and never returned. By most accounts, laughter is good medicine, the best even. But for some, such as the embarrassed diner, a good-natured chuckle isn’t funny at all. Morbidly averse to being the butt of a joke, these folks will go out of their way to avoid certain people or situations for fear of being ridiculed. For them, merely being around others who are talking and laughing can cause tension and apprehension. Until recently, such people might have been written off as spoilsports. But in the mid-1990s, an astute German psychologist recognized the problem for what it is: a debilitating fear of being laughed at. Over the past decade, psychologists, sociologists, linguists and humor experts have examined this trait, technically known as gelotophobia. Though it sounds like an ailment involving Italian ice cream, scientists worldwide now recognize it as a distinct social phobia. Studies of causes and consequences of gelotophobia were among the topics presented in June in Long Beach, Calif., at a meeting of the International Society for Humor Studies. © Society for Science & the Public 2000 - 2009

Keyword: Emotions
Link ID: 13063 - Posted: 06.24.2010

by Bijal Trivedi STANDING in line at the coffee shop you feel a little peckish. So what will you choose to keep you going until lunchtime? Will it be that scrumptious-looking chocolate brownie or perhaps a small, nut-based muesli bar. You check the labels: the brownie contains around 250 kilocalories (kcal), while the muesli bar contains more than 300. Surprised at the higher calorie count of what looks like the healthy option, you go for the brownie. This is the kind of decision that people watching their weight - or even just keeping a casual eye on it - make every day. As long as we keep our calorie intake at around the recommended daily values of 2000 for women and 2500 for men, and get a good mix of nutrients, surely we can eat whatever we like? This is broadly true; after all, maintaining a healthy weight is largely a matter of balancing calories in and calories out. Yet according to a small band of researchers, using the information on food labels to estimate calorie intake could be a very bad idea. They argue that calorie estimates on food labels are based on flawed and outdated science, and provide misleading information on how much energy your body will actually get from a food. Some food labels may over or underestimate this figure by as much as 25 per cent, enough to foil any diet, and over time even lead to obesity. As the western world's waistlines expand at an alarming rate, they argue, it is time consumers were told the true value of their food. © Copyright Reed Business Information Ltd

Keyword: Obesity
Link ID: 13062 - Posted: 06.24.2010

Emily Sohn, Discovery News -- Watching a fish or two swim around a tank can be relaxing for you -- but surprisingly stressful for the fish. A new study found that common aquarium fish fight more and act less like themselves when they're lonely. Just as people choose to squeeze into a crowded nightclub rather than roam around an empty bar, it seems, certain fish prefer to have lots of companions. It was the first study to look at the well-being of fish in home aquariums, and the results suggest that we may owe more to our fish than just keeping them from going belly-up. "I think we need to make sure they are not only alive," said Katherine Sloman, a fish biologist at the University of Plymouth in the United Kingdom. "I think we need to get them to display behaviors they might show in the wild." Advocates for the welfare of animals talk about five freedoms: freedom from hunger and thirst; freedom from discomfort; freedom from pain, injury and disease; freedom to express normal behaviors; and freedom from fear and distress. How many of those things fish can actually experience is still up for debate. Some still controversial evidence suggests that fish might feel pain. © 2009 Discovery Communications,

Keyword: Aggression
Link ID: 13061 - Posted: 06.24.2010

By DENISE GRADY A genetic test that can find an increased risk of Alzheimer’s disease does no psychological harm to people who take it, even if they test positive for a risky gene, a new study finds. The results challenge views long held by the medical establishment, which has discouraged people from being tested, arguing that the test is not definitive, that it may needlessly frighten people into thinking a terrible disease is hanging over them and that testing is pointless anyway because there is no way to cure or prevent the dementia caused by Alzheimer’s. “There has been this extraordinary worry that disclosing risk was going to devastate people,” said Dr. Robert C. Green, a professor of neurology, genetics and epidemiology at Boston University, and the lead author of the study, which is being published on Thursday in The New England Journal of Medicine. “This has upended those assumptions.” The idea behind the study was to treat information like a drug, something with risks and benefits that could be measured, Dr. Green said. Dr. Green led a large team in the study, called Reveal, in which 162 adults who had a close relative with Alzheimer’s could find out if they had the genes that increased their risk for the disease. All participants had genetic testing, but 51, picked at random, were not told the results. The other 111 were told, and the two groups were compared. Copyright 2009 The New York Times Company

Keyword: Alzheimers; Genes & Behavior
Link ID: 13060 - Posted: 06.24.2010

By PETER JARET For years, glaucoma was defined as elevated pressure within the eye that leads to vision loss. And for years experts knew there were glaring gaps in that definition. Many people with abnormally high intraocular pressure never develop glaucoma. As many as one in three people who do get the disease have normal or even low pressure. As researchers have tried to resolve those contradictions, a new paradigm for understanding glaucoma has emerged. Glaucoma isn’t simply an eye disease, experts now say, but rather a degenerative nerve disorder, not unlike Alzheimer’s or Parkinson’s disease. “All three of these diseases affect aging populations and involve selective loss of certain populations of neurons,” said Dr. Neeru Gupta, a professor of ophthalmology and director of the glaucoma unit at the University of Toronto. “Parkinson’s affects motor control. Alzheimer’s affects cognition. Glaucoma disrupts vision. But the closer we look, the more they seem to have in common.” Even the official definition of glaucoma, a disease that accounts for more than eight million cases of blindness worldwide, has changed. Today, diagnosis is based on just two features: visible damage to the optic nerve, which leads from the retina at the back of the eye to the brain, and loss of peripheral vision, which can be measured by a simple test in an eye doctor’s office. “Intraocular pressure is nowhere to be found in the definition, which shows you how the field has changed,” said Dr. Stuart McKinnon, an associate professor of ophthalmology and neurobiology at Duke University School of Medicine. Copyright 2009 The New York Times Company

Keyword: Vision
Link ID: 13059 - Posted: 06.24.2010