Chapter 8. General Principles of Sensory Processing, Touch, and Pain

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By Emily Underwood *Update, 18 May, 10 a.m.: Yesterday, the U.S. Food and Drug Administration approved the first in a new class of drugs designed to prevent migraines. This feature, originally published on 7 January 2016, describes the history of these drugs, the powerful relief they can bring some patients, and the limitations that still exist with them. As long as she can remember, 53-year-old Rosa Sundquist has tallied the number of days per month when her head explodes with pain. The migraines started in childhood and have gotten worse as she’s grown older. Since 2008, they have incapacitated her at least 15 days per month, year-round. Head-splitting pain isn’t the worst of Sundquist’s symptoms. Nausea, vomiting, and an intense sensitivity to light, sound, and smell make it impossible for her to work—she used to be an office manager—or often even to leave her light-proofed home in Dumfries, Virginia. On the rare occasions when she does go out to dinner or a movie with her husband and two college-aged children, she wears sunglasses and noise-canceling headphones. A short trip to the grocery store can turn into a full-blown attack “on a dime,” she says. Every 10 weeks, Sundquist gets 32 bee sting–like injections of the nerve-numbing botulism toxin into her face and neck. She also visits a neurologist in Philadelphia, Pennsylvania, who gives her a continuous intravenous infusion of the anesthetic lidocaine over 7 days. The lidocaine makes Sundquist hallucinate, but it can reduce her attacks, she says—she recently counted 20 migraine days per month instead of 30. Sundquist can also sometimes ward off an attack with triptans, the only drugs specifically designed to interrupt migraines after they start. © 2018 American Association for the Advancement of Science.

Keyword: Pain & Touch
Link ID: 24996 - Posted: 05.19.2018

By Gina Kolata The first medicine designed to prevent migraines was approved by the Food and Drug Administration on Thursday, ushering in what many experts believe will be a new era in treatment for people who suffer the most severe form of these headaches. The drug, Aimovig, made by Amgen and Novartis, is a monthly injection with a device similar to an insulin pen. The list price will be $6,900 a year, and Amgen said the drug will be available to patients within a week. Aimovig blocks a protein fragment, CGRP, that instigates and perpetuates migraines. Three other companies — Lilly, Teva and Alder — have similar medicines in the final stages of study or awaiting F.D.A. approval. “The drugs will have a huge impact,” said Dr. Amaal Starling, a neurologist and migraine specialist at the Mayo Clinic in Phoenix. “This is really an amazing time for my patient population and for general neurologists treating patients with migraine.” Millions of people experience severe migraines so often that they are disabled and in despair. These drugs do not prevent all migraine attacks, but can make them less severe and can reduce their frequency by 50 percent or more. As a recent editorial in the journal JAMA put it, they are “progress, but not a panacea.” Until now, drugs used to prevent migraines were designed to treat other diseases, like high blood pressure. They are not very effective, may work only temporarily, and often are laden with intolerable side effects. In clinical trials, people taking the new drugs reported no more side effects than those taking a placebo. The side effects over the long term and among people with chronic diseases remain to be determined. © 2018 The New York Times Company

Keyword: Pain & Touch
Link ID: 24994 - Posted: 05.18.2018

Katie Nicholson, Joanne Levasseur Cannabidiol oil, or CBD, is generating a lot of buzz in the world of alternative medicine and many Canadians are buying in. The oil, which is extracted from marijuana plants, doesn't have the same mind-altering effects as smoking pot. People rub it on their achy joints or put it under their tongue to help them sleep. Some purveyors say it's completely legal in Canada and can be used for a long list of ailments, including epilepsy and multiple sclerosis. But federal authorities say CBD oil, which is widely available at head shops and online, is indeed illegal without a medical marijuana prescription. And its purported health benefits are also still in question. Cannabis products not yet legal Canadian affiliates of HempWorx, a multi-level marketing company based in Las Vegas, have been pushing CBD oil products through websites that say the product is allowed in Canada. They also list how much people should take for a long list of diseases. HempWorx did not respond to multiple interview requests. But in April, one of its Winnipeg-based affiliates told CBC News that its sale is "100 per cent legal." Under current Canadian law, the possession or sale of cannabidiol oil is illegal the same way other cannabis products are illegal. The same goes for importing or exporting the substance. The fact that it doesn't get you high doesn't matter. ©2018 CBC/Radio-Canada.

Keyword: Drug Abuse; Pain & Touch
Link ID: 24961 - Posted: 05.11.2018

A new discovery shows that opioids used to treat pain, such as morphine and oxycodone, produce their effects by binding to receptors inside neurons, contrary to conventional wisdom that they acted only on the same surface receptors as endogenous opioids, which are produced naturally in the brain. However, when researchers funded by the National Institute on Drug Abuse (NIDA) used a novel molecular probe to test that common assumption, they discovered that medically used opioids also bind to receptors that are not a target for the naturally occurring opioids. NIDA is part of the National Institutes of Health. This difference between how medically used and naturally made opioids interact with nerve cells may help guide the design of pain relievers that do not produce addiction or other adverse effects produced by morphine and other opioid medicines. “This ground-breaking study has uncovered important distinctions between the opioids that our brain makes naturally and therapeutic opioids that can be misused,” said NIDA Director Nora D. Volkow, M.D. “This information can be mined to better understand the potential adverse actions of medically prescribed opioids and how to manipulate the endogenous system to achieve optimal therapeutic results without the unhealthy side effects of tolerance, dependence, or addiction.” Naturally occurring opioids and medically used opioids alike bind to the mu-opioid receptor, a member of a widespread family of proteins known as G protein-coupled receptors (GPCRs). Recent advances in understanding the three-dimensional structure of GPCRs have enabled researchers to create a new type of antibody biosensor, called a nanobody, that generates a fluorescent signal when a GPCR is activated. This enables scientists to track chemicals as they move through cells and respond to stimuli.

Keyword: Pain & Touch; Drug Abuse
Link ID: 24960 - Posted: 05.11.2018

By Aaron E. Carroll The benefits and harms of medical marijuana can be debated, but more states are legalizing pot, even for recreational use. A new evaluation of marijuana’s risks is overdue. Last year, the National Academies of Sciences, Medicine and Engineering released a comprehensive report on cannabis use. At almost 400 pages long, it reviewed both potential benefits and harms. Let’s focus on the harms. The greatest concern with tobacco smoking is cancer, so it’s reasonable to start there with pot smoking. A 2005 systematic review in the International Journal of Cancer pooled the results of six case-control studies. No association was found between smoking marijuana and lung cancer. Another 2015 systematic review pooled nine case-control studies and could find no link to head and neck cancers. Another meta-analysis of three case-control studies of testicular cancer found a statistically significant link between heavier pot smoking and one type of testicular cancer. But this evidence was judged to be “limited” because of limitations in the research (all of which was from the 1990s). There’s no evidence, or not enough to say, of a link between pot use and esophageal cancer, prostate cancer, cervical cancer, non-Hodgkin’s lymphoma, penile cancer or bladder cancer. There’s also no evidence, or not enough to say, that pot has any effect on sperm or eggs that could increase the risk of cancer in any children of pot smokers. (Using marijuana while pregnant does pose other risks, as discussed below.) Heart disease Another major risk with cigarettes, heart disease, isn’t clearly seen with pot smoking. Only two studies quantified the risk between marijuana use and heart attacks. One found no relationship at all, and the other found that pot smoking may be a trigger for a heart attack in the hour after smoking. But this finding was based on nine patients, and may not be generalizable. © 2018 The New York Times Company

Keyword: Drug Abuse; Pain & Touch
Link ID: 24948 - Posted: 05.07.2018

By Emily Underwood Getting old can be a real itch. In addition to having memory and muscle loss, many elderly people develop supersensitive skin that gets itchy at the lightest touch. Scientists don’t know what causes this miserable condition, called alloknesis, or how to treat it. Now, however, a study in mice has revealed a counterintuitive mechanism for the disorder: a loss of pressure-sensing cells in the skin. Although the findings have yet to be replicated in humans, the study raises the possibility that boosting the function of these cells could treat chronic itch in people, both young and old. Chronic itch is different from chemical itch, which occurs when the immune system reacts to a foreign substance, such as oil from a poison oak leaf or saliva in a mosquito bite. Instead, chronic—or mechanical—itch is usually triggered by light pressure, such as the brush of fibers from a sweater. The condition is maddening, and when people repeatedly scratch their fragile, dry skin, it can lead to major health problems, including infections, says study author Hongzhen Hu, an anesthesiology researcher at the Washington University School of Medicine in St. Louis, Missouri. Like people, mice visibly itch more with age. To find out why, Hu and colleagues used a hair-thin nylon filament to apply a precise amount of pressure to a patch of shaved skin on young and old rodents’ necks. Young mice didn’t respond much to the gentle touch, but the older mice scratched furiously at the spot. Analyzing skin samples from mice of both ages, the team found that older mice had far fewer pressure-sensing Merkel cells than young mice did. The fewer Merkel cells a mouse had, the more their touch-related itch problems increased in response to the filament, the researchers report today in Science. © 2018 American Association for the Advancement of Science.

Keyword: Pain & Touch; Development of the Brain
Link ID: 24941 - Posted: 05.05.2018

By Viviane Callier A human genetic variant in a gene involved in sensing cold temperatures became more common when early humans migrated out of Africa into colder climates between 20,000 and 30,000 years ago, a study published today (May 3) in PLOS Genetics shows. The advantage conferred by this variant isn’t definitively known, but the researchers suspect that it influences the gene’s expression levels, which in turn affect the degree of cold sensation. The observed pattern of positive selection strongly indicates that the allele was beneficial, but that benefit had a tradeoff—bringing with it a higher risk of getting migraines. “This paper is the latest in a series of papers showing that humans really have adapted to different environments after some of our ancestors migrated out of Africa,” explains evolutionary geneticist Rasmus Nieslen of the University of California, Berkeley, who was not involved in the study. “There are a number of adaptations associated with moving into an artic climate, but none with as clear a connection to cold as this one,” he adds. Although studies have demonstrated some striking examples of recent human adaptation, for instance, warding off infectious diseases such as malaria or having the ability to digest milk, relatively little was known about the evolutionary responses to fundamental features of the environment, namely, temperature and climate. “Obviously, humans lived in Africa for a long time, and one of the main environmental factors that changed as humans migrated north was temperature,” explains population geneticist Aida Andres. So she and Felix Key the Max Planck Institute in Leipzig homed in on a gene, TRPM8, that encodes a cation channel in the neurons that innervate the skin. It is activated by cold temperatures and necessary for sensing cold and for thermoregulation. If there was a place to look for human adaptation, this gene looked like a good candidate. © 1986-2018 The Scientist

Keyword: Pain & Touch; Evolution
Link ID: 24940 - Posted: 05.05.2018

Beth Darnall Last month, the US National Institutes of Health (NIH) formally launched a multi-agency effort to combat the country’s opioid-addiction crisis. Funds for research into controlling opioid misuse and treating pain will nearly double in 2018, to US$1.1 billion. The forces behind this epidemic extend beyond overprescription: most of the tens of thousands of deaths caused by opioid overdose in the United States each year result from illicit use. Still, an inadequate understanding about how to treat pain has certainly contributed. We need to characterize patients better, and we need more studies that incorporate non-drug treatments alongside any form of medication. Consider this crucial question: what is the first treatment you should give a person for chronic pain, or even many acute injuries? Most clinicians now agree that the answer should not be opioids. Fewer recognize that the question is not which pill to use instead, but what system of interventions — including medication — and monitoring to implement. Too often, pain is treated as a purely biomedical problem. It is a biopsychosocial condition. Psychological treatment can be combined with medication to equip people with the tools to better control their pain experience. Psychological therapies can also lower risks such as addiction, because the emphasis is on engaging patients in managing their daily actions to help themselves to feel better in the long run, rather than relying solely on passive medications. Yet a common clinical practice is to recommend such psychosocial strategies for pain only after all medications have failed. © 2018 Macmillan Publishers Limited,

Keyword: Pain & Touch
Link ID: 24935 - Posted: 05.03.2018

by Melissa Healy Sometimes forgotten in the spiraling crisis of opiate abuse is a clinical fact about narcotic pain medications: Addiction is basically an unwanted side effect of drugs that are highly effective at blunting pain. Addiction, of course, is a particularly dangerous and disruptive side effect, since it hijacks a patient’s brain and demands escalating doses of opioid drugs to hold withdrawal symptoms at bay. What if there were a drug that did the job opioids do best — relieve pain — without prompting many of their negative side effects, especially addiction? A researcher from the University of Michigan Medical School may have done just that. Tomas Joaquin Fernandez has described a process for designing opioid-like drugs that would act on pain receptors in the brain while blocking the receptors responsible for fostering dependence and building tolerance. Using pain-relieving peptides released by the brain as models, Fernandez and colleagues developed a library of “peptidomimetics.” These agents were small enough to get into the brain, and they worked on different opioid receptors in different ways. When they tested one such compound in mice, they found that it not only relieved pain, it also induced less buildup of tolerance and less physical dependence than morphine. In other words, it was less addictive. © 1996-2018 The Washington Post

Keyword: Pain & Touch; Drug Abuse
Link ID: 24918 - Posted: 04.28.2018

By Abby Olena Scientists have known for decades that many animals—including birds and sea turtles—use Earth’s magnetic field to navigate over long distances, but understanding how they do so remains a mystery. In 2015, a group from the University of Texas at Austin reported in eLife that a tiny nematode worm, Caenorhabditis elegans, orients to Earth’s magnetic field using a specific pair of neurons. The findings raised the possibility that C. elegans might be an appropriate model system to dig deeper into how animals sense magnetic fields. But earlier this month (April 13) in a comment published in eLife, researchers from the Research Institute of Molecular Pathology in Austria describe unsuccessful attempts to reproduce the results of the 2015 study. “Studying animal magnetoreception is really difficult,” says Miriam Goodman, a sensory biologist at Stanford University who is not affiliated with either group. “I think that we will remain in a situation where we have passionate disagreement until we’ve identified what cells or molecules function as receptors, and that still remains unknown,” she adds. The authors of the original study stand by their results, as they describe in a response also published in eLife. “We know a whole lot about how animals see the world and hear the world and touch it,” but magnetosensing is still something that nobody really knows much about, Andrés Vidal-Gadea, a behavioral neuroscientist at Illinois State University, tells The Scientist. As a postdoc in Jonathan Pierce’s lab at the University of Texas, Vidal-Gadea combined his interest in magnetic sensing, cultivated during a past summer as an undergraduate researcher, and his postdoctoral focus on C. elegans to investigate whether worms might detect magnetic fields. “I just thought that was really exciting, both because the behavior is fascinating and because there is so much work to be done,” he says. © 1986-2018 The Scientist

Keyword: Miscellaneous
Link ID: 24911 - Posted: 04.27.2018

By NICHOLAS BAKALAR Over-the-counter pain pills are safer and more effective than prescription opioids for controlling the pain following dental procedures, a review of the evidence has found. Researchers analyzed five reviews of studies of medication and medication combinations for pain relief. They included only reviews of high or moderate methodological quality. The data included many randomized trials on the use of oral medication for the most severe kinds of postoperative dental pain — for example, the pain following the extraction of a molar. More than three dozen drugs and drug combinations were tested in various dosages. The study is in The Journal of the American Dental Association. The researchers conclude that the most effective pain relief with the fewest side effects comes from a combination of 400 milligrams of ibuprofen (Advil and other brands) with 1,000 milligrams of acetaminophen (Tylenol). No opioid or opioid-containing medicine or any other combination of drugs was more effective. A co-author, Anita Aminoshariae, an associate professor at Case Western University, said there may be some people who can get relief only with opioids. But for most patients, she said, opioids are not only less effective, they also have unpleasant side effects, including nausea, constipation and dizziness. They also carry a high risk of addiction. “You have to start with an NSAID,” she said, meaning a nonsteroidal anti-inflammatory drug. “If that doesn’t work, add Tylenol. No one should go home in pain, but opioids should not be the first choice.” © 2018 The New York Times Company

Keyword: Pain & Touch; Drug Abuse
Link ID: 24902 - Posted: 04.26.2018

By Kerry Grens Thermometers in the mouse brain are responsible for a lack of appetite the animals feel after a vigorous workout. Simply firing up heat-sensing receptors on cells in the mouse hypothalamus can reproduce the same appetite-suppressing effects of exercise, researchers report today (April 24) in PLOS Biology. “Our study provides evidence that body temperature can act as a biological signal that regulates feeding behavior, just like hormones and nutrients do,” says coauthor Young-Hwan Jo, a neuroscientist at Albert Einstein College of Medicine, in a press release. It’s a fairly common observation among people that working out staves off hunger for a short while afterward. And it turns out the same is true in mice. Jo’s group had mice run a treadmill for 40 minutes, and observed that their brains were warmer and they ate less for the next hour. To see what might be responsible for this effect, Jo and his colleagues centered in on the hypothalamus, given its role in regulating eating. They found that in mice, neurons in the hypothalamus—specifically, in the arcuate nucleus (ARC) of the hypothalamus—produce heat-sensitive receptors called TRPV1. Through a variety of methods, including the application of capsaicin, a compound found in hot chili peppers, the investigators revealed that flipping on TRPV1 could tamp down mice’s appetites. On the flip side, disrupting the receptor wiped out the appetite-suppressing effects of exercise. © 1986-2018 The Scientist

Keyword: Obesity; Pain & Touch
Link ID: 24901 - Posted: 04.26.2018

Alexey Ponomarenko & Tatiana Korotkova The body’s basic needs include a timely supply of nutrients and the avoidance of tissue damage, which are signalled in the brain by hunger and pain, respectively. But these needs cannot be fulfilled simultaneously, because their resolution involves mutually exclusive behaviours. How does the brain prioritize the more urgent need? Writing in Cell, Alhadeff et al.1 report that the brain’s priorities are set depending on the type of pain involved. Hunger-mediating neurons suppress long-term inflammatory pain, but acute pain, which signals an immediate threat, dampens the activity of these neurons and thus deprioritizes feeding. Alhadeff and colleagues deprived mice of food for 24 hours, and analysed how the hungry animals responded to pain. The researchers found that responses to long-term inflammatory pain — of the type associated with chronic disease and recovery from injury — were reduced in the food-deprived animals compared with controls. By contrast, short-term responses to acute pain that was induced by chemicals, heat or force remained intact in hungry mice. The brain’s hypothalamus contains several structures involved in regulating food intake. One of these, the arcuate nucleus, harbours a population of neurons that express agouti-related protein (AgRP), and help to signal nutritional needs — activation of these neurons evokes voracious feeding2, whereas their ablation leads to starvation3,4. Alhadeff et al. found that stimulation of the AgRP-expressing neurons mimicked the pain-inhibiting effect of hunger in mice. By contrast, silencing of these cells blocked the reduction of inflammatory pain. © 2018 Macmillan Publishers Limited,

Keyword: Obesity; Pain & Touch
Link ID: 24896 - Posted: 04.24.2018

Maria Temming There’s a fine line between immersive and unnerving when it comes to touch sensation in virtual reality. More realistic tactile feedback in VR can ruin a user’s feeling of immersion, researchers report online April 18 in Science Robotics. The finding suggests that the “uncanny valley” — a term that describes how humanoid robots that look almost but not quite human are creepier than their more cartoonish counterparts — also applies to virtual touch (SN Online: 11/22/13). Experiment participants wearing VR headsets and gripping a controller in each hand embodied a virtual avatar holding the two ends of a stick. At first, users felt no touch sensation. Then, the hand controllers gave equally strong vibrations every half-second. Finally, the vibrations were finely tuned to create the illusion that the virtual stick was being touched in different spots. For instance, stronger vibrations in the right controller gave the impression that the stick was nudged on that side. Compared with scenarios in which users received either no touch or even buzzing sensations, participants reported feeling far less immersed in the virtual environment when they received the realistic, localized touch. This result demonstrates the existence of a tactile uncanny valley, says study coauthor Mar Gonzalez-Franco, a human-computer interaction researcher at Microsoft Research in Redmond, Washington. |© Society for Science & the Public 2000 - 2018.

Keyword: Pain & Touch; Emotions
Link ID: 24881 - Posted: 04.19.2018

Tor Wager Two soldiers receive similar injuries in battle. One recovers in months; the other endures excruciating pain for years. Why this difference? The question is pressing. One in five people suffers from chronic pain, affecting every aspect of their lives. Although significant gains have been made with anaesthetics and anti-inflammatory medications, the roots and relief of long-term pain are proving harder to find. Pain is also fuelling a global epidemic of opioid addiction and related deaths. In Chasing Men on Fire, neurologist Stephen Waxman provides a compelling portrait of scientific discovery in this area. Waxman, who works in basic research and clinical medicine, offers an insider’s account of the global search for a pain gene, beginning in 1966. He intertwines descriptions of cross-disciplinary neuroscience with portraits of scientists, and the struggles of people with conditions such as erythromelalgia, or ‘man-on-fire syndrome’, characterized by burning pain in hands and feet. Structurally, the book is innovative: 11 research papers are interlaced with the stories behind them. It is thus both a boon for researchers and an engrossing read for nonspecialists. Humans love simplicity. We want the intricate systems in our brains and bodies to ‘just work’. But Waxman shows that biology is complex, and genetic clues can be elusive. Detecting them relies on finding regularities across many people, which can make it seem impossible to pinpoint a key gene, and the rare mutations in it that lead to disease. As he reveals, it took considerable sifting and coordinated effort on three continents by scientists including pharmacologists, electrophysiologists, molecular biologists and geneticists before a ‘master gene’ for pain was isolated. © 2018 Macmillan Publishers Limited

Keyword: Pain & Touch
Link ID: 24879 - Posted: 04.19.2018

Merrit Kennedy What makes a group of animals genetically similar to each other? Traditionally, scientists have thought that animals living near each other are more likely to have things in common genetically. Another explanation is that animals living in similar environments — like high altitudes or hot temperatures — might evolve in similar ways. But loggerhead sea turtles appear to have broken that common wisdom. Their genetic similarities are closely linked to the magnetic field of the nesting area where they were born, according to new research from scientists at the University of North Carolina, Chapel Hill, published in Current Biology. And that magnetic imprinting is a better indicator of genetic similarity than that of groups of turtles that live near each other or in similar environments, says J. Roger Brothers, the lead author of the study. "A lot of different animals including sea turtles detect Earth's magnetic field and then derive navigational information from it and use it to find their way across or throughout long-distance migrations," Brothers says. Turtles likely "imprint" to the magnetic field of their nesting area at a very young age or even before they hatch. This acts like a kind of compass for them, he says, even as they leave the East Coast of the U.S. and travel hugely long distances, in some cases all the way to Africa. © 2018 npr

Keyword: Animal Migration
Link ID: 24867 - Posted: 04.14.2018

Nicola Davis A man who took part in a chilli pepper eating contest ended up with more than he bargained for when he took on the hottest pepper in the world. After eating a Carolina Reaper pepper, the 34-year-old started dry heaving before developing a pain in his neck that turned into a series of thunderclap headaches: sudden and severe episodes of excruciating pain that peak within a minute. Scoville scale: The hottest chillies in the world– in pictures The Carolina Reaper, which can top 2.2m on the Scoville heat scale, was the world’s hottest pepper at the time of the incident in 2016 – although new breeds called Pepper X and Dragon’s Breath have since reportedly surpassed it. The details, published in the journal BMJ Case Reports, reveal the pain was so terrible the man went to the emergency room at Bassett Medical Center in Cooperstown, a village in New York State. “[A thunderclap headache] lasts for a few minutes and it might be associated with dry-heaving, nausea, vomiting – and then it gets better on its own. But it keeps coming back,” said Dr Kulothungan Gunasekaran of the Henry Ford Health System in Detroit, a co-author of the report, adding that thunderclap headaches can be caused by a number of problems including bleeding inside the brain or blood clots. CT and MRI scans of the man’s brain were taken but showed nothing out of the ordinary. What’s more, the man did not report having any speech or vision problems. © 2018 Guardian News and Media Limited

Keyword: Pain & Touch; Stroke
Link ID: 24849 - Posted: 04.11.2018

Marisa Taylor, Melissa Bailey By the time Ann Marie Owen, 61, turned to marijuana to treat her pain, she was struggling to walk and talk. She was also hallucinating. For four years, her doctor prescribed a wide range of opioids for transverse myelitis, a debilitating disease that caused pain, muscle weakness and paralysis. The drugs not only failed to ease her symptoms, they hooked her. When her home state of New York legalized marijuana for the treatment of select medical ailments, Owens decided it was time to swap pills for pot. But her doctors refused to help. "Even though medical marijuana is legal, none of my doctors were willing to talk to me about it," she says. "They just kept telling me to take opioids." Cancer Patients Get Little Guidance From Doctors On Using Medical Marijuana Although 29 states have legalized marijuana to treat pain and other ailments, the growing number of Americans like Owen who use marijuana and the doctors who treat them are caught in the middle of a conflict in federal and state laws — a predicament that is only worsened by thin scientific data. Because the federal government considers marijuana a Schedule 1 drug, research on marijuana or its active ingredients is highly restricted and even discouraged in some cases. Underscoring the federal government's position, Health and Human Services Secretary Alex Azar recently pronounced that there was "no such thing as medical marijuana." © 2018 npr

Keyword: Pain & Touch; Drug Abuse
Link ID: 24844 - Posted: 04.10.2018

Aimee Cunningham A deep conviction that one’s skin is contaminated with insects or other objects despite a lack of medical evidence. She was certain her skin was infested: Insects were jumping off; fibers were poking out. Fearful her condition could spread to others, the 50-year-old patient told doctors at the Mayo Clinic in Rochester, Minn., that she was avoiding contact with her children and friends. The patient had delusional infestation, explains Mayo Clinic dermatologist Mark Davis. Sufferers have an unshaking belief that pathogens or inanimate objects pollute their skin despite no medical evidence. Davis and colleagues report online April 4 in JAMA Dermatology that the disorder is not as rare as previously assumed. In the first population-based study of the disorder’s prevalence, the researchers identified 35 cases from 1976 to 2010 reported in Minnesota’s Olmsted County. Based on the findings, the authors estimate 27 out of every 100,000 people in the United States have delusional infestation. Due to the county’s lack of diversity — the population of about 150,000 is predominantly white — the researchers used only the nationwide white population to estimate prevalence, so the result may not be representative of other populations. Delusional infestation has been recognized for decades, albeit under different names. Patients insist they’ve been overtaken with creatures, such as insects, worms or parasites, or inanimate materials like fibers — or both. © Society for Science & the Public 2000 - 2018.

Keyword: Pain & Touch
Link ID: 24836 - Posted: 04.09.2018

Maria Temming PHOENIX — High-tech attire that would give users the sensation of being pushed, pinched or poked could someday make virtual realities feel as real as they look. Today’s VR systems rely heavily on goggle-generated visual displays to transport users to simulated worlds. But superthin, shape-shifting sheets worn as sleeves or built into other garments could provide gamers with tactile feedback that makes virtual realities more immersive. The new device, described April 5 at the Materials Research Society spring meeting, contains a grid of tiny, inflatable bubbles, sandwiched between two soft, stretchy silicone films. When one of these bubble wrap–like sheets is placed against a user’s skin, inflating different air pockets by different amounts at different speeds can make a gamer feel like she’s been grabbed around the wrist or patted on the back. Some previously developed hand- or finger-worn devices have allowed wearers to feel or manipulate virtual objects. But clothing embedded with smart silicone skins could make VR gaming more of a full-body experience. Each air pocket on the sheet is coated with a liquid metal sensor that tracks how much that bubble is distended, which helps regulate the device’s shape-shifting. Those sensors also detect indentations in the bubbles, so these sleeves could work as touch pad game controllers, too, says study coauthor Matthew Robertson, a roboticist at École Polytechnique Fédérale de Lausanne in Switzerland. |© Society for Science & the Public 2000 - 2018

Keyword: Pain & Touch; Robotics
Link ID: 24831 - Posted: 04.07.2018