Chapter 8. General Principles of Sensory Processing, Touch, and Pain
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By Rachel Rabkin Peachman It began with a simple roller-skating accident three years ago. Taylor Aschenbrenner, then 8 years old, lost her balance amid a jumble of classmates, tumbled to the floor and felt someone else’s skate roll over her left foot. The searing pain hit her immediately. The diagnosis, however, would take much longer. An X-ray, M.R.I.s, a CT scan and blood tests over several months revealed no evidence of a break, sprain or other significant problem. Taylor’s primary symptom was pain — so severe that she could not put weight on the foot. “Our family doctor first told us to give it some time,” said Taylor’s mother, Jodi Aschenbrenner, of Hudson, Wis. But time didn’t heal the pain. After about a month, an orthopedist recommended physical therapy. That didn’t end the problem, either. “I couldn’t walk or play outside or do anything,” Taylor said. After she had spent a year and a half on crutches, her orthopedist suggested she see Dr. Stefan Friedrichsdorf, the medical director ofpain medicine, palliative care and integrative medicine at Children’s Hospitals and Clinics of Minnesota. He and his team promptly recognized Taylor’s condition as complex regional pain syndrome, a misfiring within the peripheral and central nervous systems that causes pain signals to go into overdrive and stay turned on even after an initial injury or trauma has healed. He came up with a treatment plan for Taylor that included cognitive behavioral therapy, physical therapy, mind-body techniques, stress-reduction strategies, topical pain-relief patches and a focus on returning to her normal life and sleep routine, among other things. © 2016 The New York Times Company
Emily Conover Sharks have a sixth sense that helps them locate prey in murky ocean waters. They rely on special pores on their heads and snouts, called ampullae of Lorenzini, that can sense electric fields generated when nearby prey move. The pores were first described in 1678, but scientists haven’t been sure how they work. Now, the answer is a bit closer. The pores, which connect to electrosensing cells, are filled with a mysterious clear jelly. This jelly is a highly efficient proton conductor, researchers report May 13 in Science Advances. In the jelly, positively charged particles move and transmit current. Marco Rolandi of the University of California, Santa Cruz and colleagues squeezed jelly from the pores of one kind of shark and two kinds of skate and tested how well protons could flow through the substance. Good proton conductors, including a protein found in squid skin, occur in nature. But the jelly is the best biological proton conductor discovered so far. In fact, even humankind’s best technology isn’t wildly better. The most efficient proton conductor devised by people — a polymer known as Nafion — is a mere 40 times better than the stuff sharks are born with. Citations E.E. Josberger et al. Proton conductivity in ampullae of Lorenzini jelly. Science Advances. Published online May 13, 2016. doi:10.1126/sciadv.1600112. Further Reading |© Society for Science & the Public 2000 - 2016.
Keyword: Pain & Touch
Link ID: 22366 - Posted: 06.28.2016
By Eric Hand That many animals sense and respond to Earth’s magnetic field is no longer in doubt, and people, too, may have a magnetic sense. But how this sixth sense might work remains a mystery. Some researchers say it relies on an iron mineral, magnetite; others invoke a protein in the retina called cryptochrome. Magnetite has turned up in bird beaks and fish noses and even in the human brain, as Joe Kirschvink of the California Institute for Technology in Pasadena reported in 1992, and it is extremely sensitive to magnetic fields. As a result, Kirschvink and other fans say, it can tell an animal not only which way it is heading (compass sense) but also where it is. “A compass cannot explain how a sea turtle can migrate all the way around the ocean and return to the same specific stretch of beach where it started out,” says neurobiologist Kenneth Lohmann of the University of North Carolina, Chapel Hill. A compass sense is enough for an animal to figure out latitude, based on changes in the inclination of magnetic field lines (flat at the equator, plunging into the earth at the poles). But longitude requires detecting subtle variations in field strength from place to place—an extra map or signpost sense that magnetite could supply, Lohmann says. Except in bacteria, however, no one has seen magnetite crystals serving as a magnetic sensor. The crystals could be something else—say, waste products of iron metabolism, or a way for the body to sequester carcinogenic heavy metals. In the early 2000s, scientists found magnetite-bearing cells in the beaks of pigeons. But a follow-up study found that the supposed magnetoreceptors were in fact scavenger immune cells that had nothing to do with the neural system. And because there is no unique stain or marker for magnetite, false sightings are easy to make. © 2016 American Association for the Advancement of Science
Keyword: Pain & Touch
Link ID: 22357 - Posted: 06.24.2016
By Eric Hand Birds do it. Bees do it. But the human subject, standing here in a hoodie—can he do it? Joe Kirschvink is determined to find out. For decades, he has shown how critters across the animal kingdom navigate using magnetoreception, or a sense of Earth’s magnetic field. Now, the geophysicist at the California Institute of Technology (Caltech) in Pasadena is testing humans to see if they too have this subconscious sixth sense. Kirschvink is pretty sure they do. But he has to prove it. He takes out his iPhone and waves it over Keisuke Matsuda, a neuroengineering graduate student from the University of Tokyo. On this day in October, he is Kirschvink’s guinea pig. A magnetometer app on the phone would detect magnetic dust on Matsuda—or any hidden magnets that might foil the experiment. “I want to make sure we don’t have a cheater,” Kirschvink jokes. They are two floors underground at Caltech, in a clean room with magnetically shielded walls. In a corner, a liquid helium pump throbs and hisses, cooling a superconducting instrument that Kirschvink has used to measure tiny magnetic fields in everything from bird beaks to martian meteorites. On a lab bench lie knives—made of ceramic and soaked in acid to eliminate magnetic contamination—with which he has sliced up human brains in search of magnetic particles. Matsuda looks a little nervous, but he will not be going under the knife. With a syringe, a technician injects electrolyte gel onto Matsuda’s scalp through a skullcap studded with electrodes. He is about to be exposed to custom magnetic fields generated by an array of electrical coils, while an electroencephalogram (EEG) machine records his brain waves. © 2016 American Association for the Advancement of Science.
Keyword: Pain & Touch
Link ID: 22356 - Posted: 06.24.2016
By BARRY MEIER and ABBY GOODNOUGH A few months ago, Douglas Scott, a property manager in Jacksonville, Fla., was taking large doses of narcotic drugs, or opioids, to deal with the pain of back and spine injuries from two recent car accidents. The pills helped ease his pain, but they also caused him to withdraw from his wife, his two children and social life. “Finally, my wife said, ‘You do something about this or we’re going to have to make some changes around here,’” said Mr. Scott, 43. Today, Mr. Scott is no longer taking narcotics and feels better. Shortly after his wife’s ultimatum, he entered a local clinic where patients are weaned off opioids and spend up to five weeks going through six hours of training each day in alternative pain management techniques such as physical therapy, relaxation exercises and behavior modification. Mr. Scott’s story highlights one patient’s success. Yet it also underscores the difficulties that the Obama administration and public health officials face in reducing the widespread use of painkillers like OxyContin and Percocet. The use and abuse of the drugs has led to a national epidemic of overdose deaths, addiction and poor patient outcomes. In recent months, federal agencies and state health officials have urged doctors to first treat pain without using opioids, and some have announced plans to restrict how many pain pills a doctor can prescribe. But getting the millions of people with chronic pain to turn to alternative treatments is a daunting task, one that must overcome inconsistent insurance coverage as well as some resistance from patients and their doctors, who know the ease and effectiveness of pain medications. “We are all culpable,” said Dr. David Deitz, a former insurance industry executive and a consultant on pain treatment issues. “I don’t care whether you are a doctor, an insurer or a patient.” © 2016 The New York Times Compan
Keyword: Pain & Touch
Link ID: 22352 - Posted: 06.23.2016
By Teal Burrell Sociability may be skin deep. The social impairments and high anxiety seen in people with autism or related disorders may be partly due to a disruption in the nerves of the skin that sense touch, a new study in mice suggests. Autism spectrum disorders are primarily thought of as disorders of the brain, generally characterized by repetitive behaviors and deficits in communication skills and social interaction. But a majority of people with autism spectrum disorders also have an altered tactile sense; they are often hypersensitive to light touch and can be overwhelmed by certain textures. “They tend to be very wary of social touch [like a hug or handshake], or if they go outside and feel a gust of wind, it can be very unnerving,” says neuroscientist Lauren Orefice from Harvard Medical School in Boston. An appreciation for this sensory aspect of autism has grown in recent years. The newest version of psychiatry’s bible, the Diagnostic and Statistical Manual of Mental Disorders, includes the sensory abnormalities of autism as core features of the disease. “That was a big nod and a recognition that this is a really important aspect of autism,” says Kevin Pelphrey, a cognitive neuroscientist at The George Washington University in Washington, D.C., who was not involved in the work. The sensation of touch starts in the peripheral nervous system—in receptors at the surface of the skin—and travels along nerves that connect into the central nervous system. Whereas many autism researchers focus on the end of the pathway—the brain—Orefice and colleagues wondered about the first leg of the trip. So the group introduced mutations that silenced genes associated with autism spectrum disorders in mice, adding them in a way that restricted the effects to peripheral nerve cells, they report today in Cell. The team singled out the gene Mecp2, which encodes a protein that regulates the expression of genes that help forge connections between nerve cells. © 2016 American Association for the Advancement of Science
By ANNA FELS ONE of the most painful experiences of being a psychiatrist is having a patient for whom none of the available therapies or medications work. A while back, I was asked to do a consultation on just such a patient. This person had been a heroin addict in her early 20s. She had quit the opioid five years earlier, but her life was plagued with anxiety, apathy and self-doubt that prior treatments had not helped. At the end of the session, almost as an afterthought, she noted with irony that the only time in her adult life when she had been able to socialize easily and function at work was when she had been hooked on heroin. We are in the midst of a devastating and often lethal opioid epidemic, one of whose victims, we learned last week, was the pop star Prince. At such a time, it is hard to remember that there are multiple opioids naturally produced in our brains and required for our well-being. The neural circuitry utilizing these substances controls some of our most fundamental feelings of pain, stress and hopelessness, as well as pleasure and even euphoria. There is obviously a need for extreme caution, but research suggests that certain opioids may actually be useful in treating psychiatric diseases that have proved frustratingly unresponsive to current medications. It is the potentially addictive subset of opioids, whose natural ancestors were originally derived from poppies, that we associate with the word. These substances have been with us for most, if not all, of human civilization. Poppy seeds have been found at archaeological sites of Neolithic man. The Sumerians wrote about “the joy plant”; an Egyptian papyrus from the second millennium B.C. described the use of a product of poppies to stop the crying of children. Hippocrates suggested its use for female ailments, and a ninth-century Persian physician advocated the use of opium for melancholia. Millenniums later, during the American Civil War, the Union Army used 10 million opium pills to treat wounded soldiers. And then there were the two Opium Wars fought between China and Britain. Unquestionably, no other psychoactive substance has played such a central role in human affairs. © 2016 The New York Times Company
By JOHN ELIGON and SERGE F. KOVALESKI Prince, the music icon who struggled with debilitating hip pain during his career, died from an accidental overdose of self-administered fentanyl, a type of synthetic opiate, officials in Minnesota said Thursday. The news ended weeks of speculation about the sudden death of the musician, who had a reputation for clean living but who appears to have developed a dependency on medications to treat his pain. Authorities have yet to discuss how he came to be in possession of the fentanyl and whether it had been prescribed by a doctor. Officials had waited several weeks for the results of a toxicology test undertaken as part of an autopsy performed after he was found dead April 21 in an elevator at his estate. He was preparing to enroll in an opioid treatment program when he died at 57, according to the lawyer for a doctor who was planning to treat him. The Midwest Medical Examiner’s Office, which conducted the autopsy, declined to comment beyond releasing a copy of its findings. The Carver County Sheriff’s Office is continuing to investigate the death with help from the federal Drug Enforcement Administration. The sheriff’s office had said it was looking into whether opioid abuse was a factor, and a law enforcement official had said that painkillers were found on Prince when investigators arrived. “The M.E. report is one piece of the whole thing,” said Jason Kamerud, the county’s chief deputy sheriff. Fentanyl is a potent but dangerous painkiller, estimated to be more than 50 times more powerful than heroin, according to the Centers for Disease Control and Prevention. The report did not list how much fentanyl was found in Prince’s blood. Last year, federal officials issued an alert that said incidents and overdoses with fentanyl were “occurring at an alarming rate throughout the United States.” © 2016 The New York Times Company
By Kelly Servick There’s an unfortunate irony for people who rely on morphine, oxycodone, and other opioid painkillers: The drug that’s supposed to offer you relief can actually make you more sensitive to pain over time. That effect, known as hyperalgesia, could render these medications gradually less effective for chronic pain, leading people to rely on higher and higher doses. A new study in rats—the first to look at the interaction between opioids and nerve injury for months after the pain-killing treatment was stopped—paints an especially grim picture. An opioid sets off a chain of immune signals in the spinal cord that amplifies pain rather than dulling it, even after the drug leaves the body, the researchers found. Yet drugs already under development might be able to reverse the effect. It’s no secret that powerful painkillers have a dark side. Overdose deaths from prescription opioids have roughly quadrupled over 2 decades, in near lockstep with increased prescribing. And many researchers see hyperalgesia as a part of that equation—a force that compels people to take more and more medication, while prolonging exposure to sometimes addictive drugs known to dangerously slow breathing at high doses. Separate from their pain-blocking interaction with receptors in the brain, opioids seem to reshape the nervous system to amplify pain signals, even after the original illness or injury subsides. Animals given opioids become more sensitive to pain, and people already taking opioids before a surgery tend to report more pain afterward. © 2016 American Association for the Advancement of Scienc
By Viviane Callier Bees don’t just recognize flowers by their color and scent; they can also pick up on their minute electric fields. Such fields—which form from the imbalance of charge between the ground and the atmosphere—are unique to each species, based on the plant’s distance from the ground and shape. Flowers use them as an additional way to advertise themselves to pollinators, but until now researchers had no idea how bees sensed these fields. In a new study, published online today in the Proceedings of the National Academy of Sciences, researchers used a laser vibrometer—a tiny machine that hits the bee hair with a laser—to measure how the hair on a bee’s body responds to a flower’s tiny electric field. As the hair moves because of the electric field, it changes the frequency of the laser light that hits it, allowing the vibrometer to keep track of the velocity of motion of the hair. When the bees buzzed within 10 centimeters of the flower, the electric field—like static electricity from a balloon—caused the bee’s hair to bend. This bending activates neurons at the base of bee hair sockets, which allows the insects to “sense” the field, the team found. Electric fields can only be sensed from a distance of 10 cm or so, so they’re not very useful for large animals like ourselves. But for small insects, this distance represents several body lengths, a relatively long distance. Because sensing such fields is useful to small animals, the team suspects this ability could be important to other insect species as well. © 2016 American Association for the Advancement of Science.
Keyword: Pain & Touch
Link ID: 22263 - Posted: 05.31.2016
By Jessica Hamzelou People who experience migraines that are made worse by light might be better off seeing the world in green. While white, blue, red and amber light all increase migraine pain, low-intensity green light seems to reduce it. The team behind the finding hope that specially developed sunglasses that screen out all wavelengths of light except green could help migraineurs. Many people experience sensitivity to light during a migraine. Photophobia, as it is known, can leave migraineurs resorting to sunglasses in well-lit rooms, or seeking the comfort of darkness. The reaction is thought to be due to the brain’s wiring. In a brain region called the thalamus, neurons that transmit sensory information from our retinas cross over with other neurons that signal pain. As a result, during migraine, light can worsen pain and pain can cause visual disturbance, says Rami Burstein at Harvard University. But not all colours of light have the same effect. Six years ago, Burstein and his colleagues studied migraine in sufferers who are blind, either due to the loss of an eye or retina, or because of retinal damage. They found that people who had some remaining retinal cells had worse migraines when they were in brightly lit environments, and that blue light seemed to have the strongest impact. The finding caused a flurry of excitement, and the promotion of sunglasses that filter out blue light. © Copyright Reed Business Information Ltd.
By Adam Gopnik On a bitter, soul-shivering, damp, biting gray February day in Cleveland—that is to say, on a February day in Cleveland—a handless man is handling a nonexistent ball. Igor Spetic lost his right hand when his forearm was pulped in an industrial accident six years ago and had to be amputated. In an operation four years ago, a team of surgeons implanted a set of small translucent “interfaces” into the neural circuits of his upper arm. This afternoon, in a basement lab at a Veterans Administration hospital, the wires are hooked up directly to a prosthetic hand—plastic, flesh-colored, five-fingered, and articulated—that is affixed to what remains of his arm. The hand has more than a dozen pressure sensors within it, and their signals can be transformed by a computer into electric waves like those natural to the nervous system. The sensors in the prosthetic hand feed information from the world into the wires in Spetic’s arm. Since, from the brain’s point of view, his hand is still there, it needs only to be recalled to life. Now it is. With the “stimulation” turned on—the electronic feed coursing from the sensors—Spetic feels nineteen distinct sensations in his artificial hand. Above all, he can feel pressure as he would with a living hand. “We don’t appreciate how much of our behavior is governed by our intense sensitivity to pressure,” Dustin Tyler, the fresh-faced principal investigator on the Cleveland project, says, observing Spetic closely. “We think of hot and cold, or of textures, silk and cotton. But some of the most important sensing we do with our fingers is to register incredibly minute differences in pressure, of the kinds that are necessary to perform tasks, which we grasp in a microsecond from the feel of the outer shell of the thing. We know instantly, just by touching, whether to gently squeeze the toothpaste or crush the can.”
Keyword: Pain & Touch
Link ID: 22215 - Posted: 05.14.2016
By JAN HOFFMAN The pop superstar Prince may have lived an outsize life, but emerging details about his long struggle with pain and reliance on opioids will resonate with thousands of patients who have stumbled down that well-trod path. It is a remarkably common narrative in the unfolding story of the nation’s opioid epidemic. Many details have yet to be confirmed about Prince’s case, but a typical trajectory can go something like this. A patient undergoes a procedure to address a medical issue — extracted wisdom teeth for example, or, as Prince did, orthopedic surgery. To help the patient get through recovery, a dentist or surgeon writes a prescription for opioid painkillers, like Percocet or Vicodin. Procedure over, problem addressed. But that prescription may not be written judiciously. “Opioids may be required after a procedure for a few days, but sometimes, physicians practice sloppy prescribing habits and they give patients much more than they need,” said Dr. Patrick G. O’Connor, a professor of medicine at Yale School of Medicine and a past president of the American Board of Addiction Medicine. “And the more patients take, the more likely they are to become dependent.” After a follow-up visit or two, the specialist who did the procedure has no reason to continue seeing the patient. (That doctor could also be an emergency room physician who treated kidney stones, sciatica or any number of other conditions involving stabbing pain.) Yet the patient’s pain may persist, demanding to be tamed. The patient, who now knows just how effective these drugs are, wants to refill the prescription. “The default approach is you go to your primary care provider, and they’ll take care of it,” said Dr. Jonathan H. Chen, an instructor at the Stanford University School of Medicine, who has researched the distribution of opioid prescriptions. As he spoke during a break in his shift in a same-day urgent care clinic, he had just attended to a patient who had recently had shoulder surgery but said she was still in pain. © 2016 The New York Times Company
Nicola Davis People with a larger circle of friends are better able to tolerate pain, according to research into the pain thresholds and social networks of volunteers. The link is thought to be down a system in the brain that involves endorphins: potent pain-killing chemicals produced by the body that also trigger a sense of wellbeing. “At an equivalent dose, endorphins have been shown to be stronger than morphine,” said Katerina Johnson, a doctoral student at the University of Oxford, who co-authored the research. Writing in the journal Scientific Reports, Johnson and Robin Dunbar, professor of evolutionary psychology at the University of Oxford, sought to probe the theory that the brain’s endorphin system might have evolved to not only handle our response to physical discomfort, but influence our experience of pleasure from social interactions too. “Social behaviour and being attached to other individuals is really important for our survival - whether that is staying close to our parents, or our offspring or cooperating with others to find food or to help defend ourselves,” said Johnson. To test the link, the authors examined both the social networks and pain thresholds of 101 adults aged between 18 and 34. Each participant was asked to complete a questionnaire, designed to quiz them on friends they contacted once a week and those they got in touch with once a month. The personality of each participant was probed, looking at traits such as “agreeableness”; they were also asked to rate their fitness and stress levels. © 2016 Guardian News and Media Limited
Keyword: Pain & Touch
Link ID: 22156 - Posted: 04.28.2016
Medical research and new drugs to treat human illness usually start with studies on mice and rats. But that type of research has been traditionally sexist — using far more male than female rodents. Scientists warn that has already led to drugs and treatments that are potentially dangerous for women and say the approach slows down the development of treatments and drugs that are safe and effective for everyone. Cara Tannenbaum, scientific director of the Institute of Gender and Health at the Canadian Institutes of Health Research, cited a couple of examples on CBC's The Current of cases where drug side-effects turned out to be far more harmful in women: A stomach drug called cisapride that was sold in the 1990s under the name Prepulsid was withdrawn by Health Canada in 2000 because it sometimes caused irregular heartbeat and sudden death "in women only," Tannenbaum said. Among the victims was the 15-year-old daughter of former Ontario MP Terence Young. "It's not clear that the drug was ever tested in female animals or minors," Tannenbaum added. Health Canada has issued a warning about sleeping pills containing the drug zolpiclone, also known as Ambien, Tannenbaum said. Women are recommended to take half the dose that is prescribed to men. "It was recently discovered that the level of the drug was 45 per cent higher in women the next day, which can lead to car accidents," Tannenbaum said. Jeffrey Mogil, a neuroscientist and pain specialist at McGill University, said there are lots of reasons to suspect men and women respond differently to many different kinds of drugs, but very little actual data. "We actually don't know the scope of the problem," he told The Current. ©2016 CBC/Radio-Canada.
Dr. Perri Klass First of all, nobody takes a small child on an airplane for the fun of it. I have been there and I know. Don’t get me wrong, I’m no airplane saint; you won’t generally catch me offering to hold someone else’s kid, or making friends around the seatback. I don’t usually admit to being a pediatrician, for fear of hearing a medical saga. But I have put in my time on airplanes with my own infants and toddlers and small children, and I certainly know how it feels. Probably the best thing that can be said for traveling with young children is that it teaches you to appreciate traveling without them, however puzzling the inflight announcements, however long the delays, however tightly spaced the seats. I did enough economy-class traveling with children while my own were young that my reflexive reaction to all flight cancellations, turbulence or the moment when the person in front of me reclines the seat very suddenly, knocking my laptop closed, is now: At least I don’t have a small child with me – thank heavens. Babies do not cry on airplanes for the fun of it either. Nor do they cry, by and large, to let you know that their parents are neglectful or callous. They cry for infant versions of the same reasons that adults snap at one another about reclining seats, or elbow each other with quiet savagery over the armrest. They cry because their ears hurt and they’re being made to stay in a certain position when they don’t want to or the air smells strange and the noises are loud, or their stomachs feel upset or the day has been too long and they still aren’t there yet or they’re just plain cranky. As are we all. Crying is an evolutionary strategy to summon adult aid; over millennia, crying has probably evolved to be hard to ignore. I don’t know if it’s any comfort, but when you’re the parent with the crying baby, it doesn’t particularly help to be an expert. “I remember one flight where my daughter screamed the whole way and kept trying to get out of her seatbelt,” said my old friend, Dr. Elizabeth Barnett, a professor of pediatrics at Boston University and a travel medicine specialist. “As a parent, you feel two things — you’re in distress because you’re trying to comfort your child and not succeeding, so you feel bad for your child, and you also feel guilty because you know your child is disturbing everybody else.” © 2016 The New York Times Company
By JOANNA KLEIN Misconception: Migraines are psychological manifestations of women’s inability to manage stress and emotions Actually: Neurologists are very clear that migraines are a real, debilitating medical condition related to temporary abnormal brain activity. The fact that they may be more common for some women during “that time of the month” has nothing to do with emotions. For centuries, doctors explained migraines as a woman’s problem caused by emotional disturbances like hysteria, depression or stress. “Bizarrely, the recommended cure was marriage!” said Dr. Anne MacGregor, the lead author of the British Association for the Study of Headache’s guidelines for diagnosing and managing migraines. While that prescription may be far behind us, the misconception that migraines are fueled by a woman’s inability to cope persists. “It was considered psychological, or that I was a nervous overachiever, so I would never tell people that I have them,” said Lorie Novak, an artist in her sixties who has suffered from migraines since she was 8. After reading Joan Didion’s 1968 essay “In Bed,” about the writer’s struggle with migraines, Ms. Novak decided to tackle the representation of these debilitating headaches. Starting in 2009, Ms. Novak photographed herself every time she got a migraine. Under the hashtag #notjustaheadache, hundreds of others on Twitter and Instagram have demonstrated their own frustration with a widespread lack of understanding of the reality of migraines. © 2016 The New York Times Company
By Sandhya Somashekhar African Americans are routinely under-treated for their pain compared with whites, according to research. A study released Monday sheds some disturbing light on why that might be the case. Researchers at the University of Virginia quizzed white medical students and residents to see how many believed inaccurate and at times "fantastical" differences about the two races -- for example, that blacks have less sensitive nerve endings than whites or that black people's blood coagulates more quickly. They found that fully half thought at least one of the false statements presented was possibly, probably or definitely true. Moreover, those who held false beliefs often rated black patients' pain as lower than that of white patients and made less appropriate recommendations about how they should be treated. The study, published in the Proceedings of the National Academy of Sciences, could help illuminate one of the most vexing problems in pain treatment today: That whites are more likely than blacks to be prescribed strong pain medications for equivalent ailments. A 2000 study out of Emory University found that at a hospital emergency department in Atlanta, 74 percent of white patients with bone fractures received painkillers compared with 50 percent of black patients. Similarly, a paper last year found that black children with appendicitis were less likely to receive pain medication than their white counterparts. And a 2007 study found that physicians were more likely to underestimate the pain of black patients compared with other patients.
By C. CLAIBORNE RAY Q. Why do we become desensitized to a perfume we are wearing while others can still smell it? A. Ceasing to smell one’s perfume after continuous exposure while casual passers-by can still smell it is just one example of a phenomenon called olfactory adaptation or odor fatigue. After some time without exposure, sensitivity is usually restored. A similar weakening of odor signals with continued exposure also takes place in animals other than humans, and researchers often rely on animal studies to try to understand the cellular and molecular bases for the condition. It has been suggested that odor fatigue is useful because it enables animals to sort out the signals of a new odor from the background noise of continuous odors. It may also enable them to sense when an odor grows stronger. Studies published in the journal Science in 2002 pinpointed a chemical that seems to act as a gatekeeper for neurons involved in smell, opening and closing their electric signal channels. Genetically engineered mice that did not produce the substance, a protein called CNGA4, had profoundly impaired olfactory adaptation. A separate test-tube study found similar changes on a cellular level, with the signal channels remaining open when CNGA4 was absent. firstname.lastname@example.org © 2016 The New York Times Company
Keyword: Chemical Senses (Smell & Taste)
Link ID: 22042 - Posted: 03.29.2016
By Roni Caryn Rabin Sixty-five million Americans suffer from chronic lower back pain, and many feel they have tried it all: physical therapy, painkillers, shots. Now a new study reports many people may find relief with a form of meditation that harnesses the power of the mind to manage pain. The technique, called mindfulness-based stress reduction, involves a combination of meditation, body awareness and yoga, and focuses on increasing awareness and acceptance of one’s experiences, whether they involve physical discomfort or emotional pain. People with lower back pain who learned the meditation technique showed greater improvements in function compared to those who had cognitive behavioral therapy, which has been shown to help ease pain, or standard back care. Participants assigned to meditation or cognitive behavior therapy received eight weekly two-hour sessions of group training in the techniques. After six months, those learning meditation had an easier time doing things like getting up out of a chair, going up the stairs and putting on their socks, and were less irritable and less likely to stay at home or in bed because of pain. They were still doing better a year later. The findings come amid growing concerns about opioid painkillers and a surge of overdose deaths involving the drugs. At the beginning of the trial, 11 percent of the participants said they had used an opioid within the last week to treat their pain, and they were allowed to continue with their usual care throughout the trial. “This new study is exciting, because here’s a technique that doesn’t involve taking any pharmaceutical agents, and doesn’t involve the side effects of pharmaceutical agents,” said Dr. Madhav Goyal of Johns Hopkins University School of Medicine, who co-wrote an editorial accompanying the paper. © 2016 The New York Times Company