Chapter 9. Hearing, Balance, Taste, and Smell

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By Roni Caryn Rabin Until March, when everything started tasting like cardboard, Katherine Hansen had such a keen sense of smell that she could recreate almost any restaurant dish at home without the recipe, just by recalling the scents and flavors. Then the coronavirus arrived. One of Ms. Hansen’s first symptoms was a loss of smell, and then of taste. Ms. Hansen still cannot taste food, and says she can’t even tolerate chewing it. Now she lives mostly on soups and shakes. “I’m like someone who loses their eyesight as an adult,” said Ms. Hansen, a realtor who lives outside Seattle. “They know what something should look like. I know what it should taste like, but I can’t get there.” A diminished sense of smell, called anosmia, has emerged as one of the telltale symptoms of Covid-19, the illness caused by the coronavirus. It is the first symptom for some patients, and sometimes the only one. Often accompanied by an inability to taste, anosmia occurs abruptly and dramatically in these patients, almost as if a switch had been flipped. Most regain their senses of smell and taste after they recover, usually within weeks. But in a minority of patients like Ms. Hansen, the loss persists, and doctors cannot say when or if the senses will return. Scientists know little about how the virus causes persistent anosmia or how to cure it. But cases are piling up as the coronavirus sweeps across the world, and some experts fear that the pandemic may leave huge numbers of people with a permanent loss of smell and taste. The prospect has set off an urgent scramble among researchers to learn more about why patients are losing these essential senses, and how to help them. “Many people have been doing olfactory research for decades and getting little attention,” said Dr. Dolores Malaspina, professor of psychiatry, neuroscience, genetics and genomics at Icahn School of Medicine at Mount Sinai in New York. “Covid is just turning that field upside down.” © 2021 The New York Times Company

Keyword: Chemical Senses (Smell & Taste)
Link ID: 27642 - Posted: 01.09.2021

By Matthew Hutson Somehow, even in a room full of loud conversations, our brains can focus on a single voice in something called the cocktail party effect. But the louder it gets—or the older you are—the harder it is to do. Now, researchers may have figured out how to fix that—with a machine learning technique called the cone of silence. Computer scientists trained a neural network, which roughly mimics the brain’s wiring, to locate and separate the voices of several people speaking in a room. The network did so in part by measuring how long it took for the sounds to hit a cluster of microphones in the room’s center. When the researchers tested their setup with extremely loud background noise, they found that the cone of silence located two voices to within 3.7º of their sources, they reported this month at the online-only Conference on Neural Information Processing Systems. That compares with a sensitivity of only 11.5º for the previous state-of-the-art technology. When the researchers trained their new system on additional voices, it managed the same trick with eight voices—to a sensitivity of 6.3º—even if it had never heard more than four at once. Such a system could one day be used in hearing aids, surveillance setups, speakerphones, or laptops. The new technology, which can also track moving voices, might even make your Zoom calls easier, by separating out and silencing background noise, from vacuum cleaners to rambunctious children. © 2020 American Association for the Advancement of Science.

Keyword: Hearing
Link ID: 27628 - Posted: 12.19.2020

By Paula Span By now, we were supposed to be swiftly approaching the day when we could walk into a CVS or Walgreens, a Best Buy or Walmart, and walk out with a pair of quality, affordable hearing aids approved by the Food and Drug Administration. Hearing aids, a widely needed but dauntingly expensive investment, cost on average $4,700 a pair. (Most people need two.) So in 2017, Congress passed legislation allowing the devices to be sold directly to consumers, without a prescription from an audiologist. The next step was for the F.D.A. to issue draft regulations to establish safety and effectiveness benchmarks for these over-the-counter devices. Its deadline: August 2020. A public comment period would follow, and then — right about now — the agency would be preparing its final rule, to take effect in May 2021. So by next summer, people with what is known as “perceived mild to moderate hearing loss” might need to spend only one-quarter of today’s price or less, maybe far less. And then we could have turned down the TV volume and stopped making dinner reservations for 5:30 p.m., when restaurants are mostly empty and conversations are still audible. “These regulations are going to help a lot of people,” said Dr. Vinay Rathi, an otolaryngologist at Massachusetts Eye and Ear. “There could be great potential for innovation.” So, where are the new rules? This long-sought alternative to the current state of hearing aid services has been delayed, perhaps one more victim of the pandemic. Of course, the agency has other crucial matters to address just now. Although the office charged with hearing aid regulations is not the one assessing Covid-19 vaccines, an F.D.A. spokesman said via email that it was dealing with “an unprecedented volume of emergency use authorizations” for diagnostics, ventilators and personal protective equipment. © 2020 The New York Times Company

Keyword: Hearing
Link ID: 27626 - Posted: 12.15.2020

Sam Wollaston A single-storey building in a lonely rural business park, a few miles from Milton Keynes on a grey autumn day. It looks like a location for a bleak thriller: where a kidnap victim is held, perhaps, or the scene of a final shootout. Inside, though, something kind of cool is happening. In a brightly lit room, four inverted metal cups have been placed on the red carpet, each containing a small glass jar. One of these contains a smell: a “training odour”. Into the room bursts Billy, followed by Jess. Billy is a labrador, and Jess his human trainer. Billy bounces about the place, clearly super excited. He sniffs at everything – furniture, people, the cups – wagging ferociously. When he sniffs at the cup that contains the smell, another trainer, Jayde, indicates success with a clicking noise. Billy is rewarded with his favourite toy, a well-chewed rubber ball, and a chorus of “good boy”. So far, so unremarkable. Dogs have excellent noses, everyone knows that. They are estimated to be at least 10,000 times better than ours. It’s not immediately clear just how good Billy is. Did he really find the smell, or did Jayde just click when he sniffed the right cup? To be fair to Billy, he’s young, 18 months old, and this is only his second session. The trainers – Jess, Jayde and Mark – have high hopes for him. And after a couple more goes, it becomes clear that he is definitely finding the right cup, quickly. He is also clearly enjoying the game. What Billy lacks in refinement, he makes up for in youthful enthusiasm and exuberance, and he learns fast. Which is good news: this is just the first stage for Billy, who is on a fast-track training course to learn to sniff out Covid-19. He’s not working with the actual virus, of course, but a training sample, which will teach him to do that job. © 2020 Guardian News & Media Limited

Keyword: Chemical Senses (Smell & Taste)
Link ID: 27622 - Posted: 12.12.2020

By Jason Castro To be an expectant mother, or the anxious partner of one, is to be keenly, even agonizingly aware of how chemicals affect a developing life. The basic advice is well known, and obsessively followed: Alcohol in strict moderation, and no nicotine at all. Don’t mess with mercury. Folic acid is your friend. More protein and less caffeine. Stay away from BPA, PBCs and PFA, and generally make an enemy of the unpronounceable. But, if we take the results of a provocative recent paper seriously, there may be another important, and deeply underappreciated chemical influence at work: a man’s odor. The research, by a team headed by Noam Sobel of the Weizmann Institute of Science, suggests that there is a relationship between women’s response to “social odors” contained in male sweat and the heartbreaking condition of unexplained repeated pregnancy loss (uRPL). Specifically, in blind smell-tests, these scientists observed that women who had experienced uRPL were significantly better at identifying their spouse’s odor than age-matched controls. Additionally, their brains responded differently to nonspouse odors and they displayed unique olfactory neuroanatomy. Taken in the context of a large body of literature on chemosignaling in nonhuman animals, these results make it conceivable that the human nose could also communicate with the womb and may even influence a pregnancy. So far, the results are strictly correlative, and in no way point to male odor as some kind of pheromonal smoking gun that explains pregnancy loss. Hypothetically, it could also be true that women experiencing uRPL have, on average, larger middle toes, larger whites of their eyes, thinner wrists and a proclivity for wearing purple socks. None of these would give one pause or prompt a serious search for some kind of causal link to pregnancy loss. Yet this particular link between smell and pregnancy loss is intriguing because of how prevalent and robust it is in other mammals, including primates. Many miscarriages still have unexplained causes, which makes any lead, correlative or not, a particularly interesting and worthwhile area of research. © 2020 Scientific American

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 27619 - Posted: 12.09.2020

David Cox Seven years ago, rhinology surgeon Peter Andrews found himself performing an operation that would go on to change the course of his career. Andrews was operating on a patient who had broken his nose many decades earlier after being struck by a cricket ball. The procedure was delicate: straightening the septum – the thin wall of cartilage that separates the nostrils – and in the process improving his breathing, which had become more laboured in later life. But it had a surprising outcome. As well being able to breathe more freely, Andrews’s patient found he could smell again for the first time in 40 years, a remarkable turn of events that provided the medical community with a new insight into our sense of smell, and its capacity to regenerate. Being able to smell is actually a result of a complex neurological process. Smell-specific nerve cells known as olfactory neurons, located high in the nasal cavity, detect molecules in the air such as those released by a perfume, or smoke particles from something burning. They then convey this information via a long nerve fibre running up through the skull, to a part of the brain that makes sense of it all. This network is one of the most adaptable in the entire central nervous system. To keep functioning, it completely regenerates every six weeks, shedding existing olfactory neurons, and creating new ones from scratch. “That’s quite a feat in itself, because those neurons then have to reconnect up into the brain tissue,” says Andrews. But sometimes things can happen that impair its ability to regenerate. An estimated 5% of the general population is believed to have anosmia, the medical term for temporary or permanent smell loss. Anosmia can occur as part of the ageing process, but also in those of all ages due to factors ranging from broken noses to viral infections. © 2020 Guardian News & Media Limited

Keyword: Chemical Senses (Smell & Taste)
Link ID: 27618 - Posted: 12.09.2020

By Mekado Murphy Creating an audioscape for a movie about a musician losing his hearing is more complicated than it may seem. The filmmakers behind the new drama “Sound of Metal” wanted to take audiences into the experience of its lead character, Ruben (Riz Ahmed), a punk-metal drummer who is forced to look at his life differently as he goes deaf. Judging by the overwhelmingly positive reviews, the filmmakers pulled off that difficult feat. In The New York Times, Jeannette Catsoulis raved about “an extraordinarily intricate sound design that allows us to borrow Ruben’s ears.” The film (streaming on Amazon) often places us in Ruben’s aural perspective as he navigates his new reality. (It’s worth watching with headphones or a good sound system.) “I had many conversations with people who have lost their hearing and not two people’s experience is the same,” said Darius Marder, the film’s co-writer and director. “But one thing that’s pretty much true for all people who are deaf is that they don’t lose sound entirely. It isn’t silence.” Instead, Marder and his sound designer, Nicolas Becker, wanted to capture those low-frequency vibrations and other tones. The approach was adjusted for different moments in Ruben’s experience. In separate Zoom interviews, Marder and Becker focused on three scenes as they spoke about some of the techniques and ideas they used to tap into Ruben’s aural experience, including putting microphones inside skulls and mouths. If the first times there’s a notable change in Ruben’s hearing comes before a show, as he is setting up the merchandise table with his bandmate and girlfriend, Lou (Olivia Cooke). At one point, he experiences a high-pitched ringing, then voices are muffled. Ahmed’s response in that moment isn’t just acting. The filmmakers had custom-fit earpieces made for the actor so they could feed him a high-frequency sound they had created. © 2020 The New York Times Company

Keyword: Hearing
Link ID: 27606 - Posted: 12.05.2020

Terry Gross Food science writer Harold McGee was in the middle of writing Nose Dive, his book about the science of smell, when he woke up one morning and realized that he couldn't smell his own coffee. Loss of smell has since become associated with COVID-19. In McGee's case, it was the byproduct of a sinus infection. McGee remembers feeling panicked. "I have friends in the kind of clinical side of taste and smell research. And so I immediately contacted them to find out what I could do and why this had happened," he says. "And they basically said, 'You're going to have to wait and see.' " Over the course of a few months, McGee's sense of smell gradually returned. But he still remembers what it was like to live in an odorless world. "It's the kind of thing where you don't notice something until it's gone," he says. "I spent less and less time cooking. There was no point in going out to restaurants because I wasn't really going to enjoy it." McGee's new book is about how smell is essential to our sense of taste, why things smell the way they do and the ways different chemicals combine to create surprising (and sometimes distasteful) odors. "One of the great pleasures of delving into smells in general was discovering over and over again that things that we enjoy in foods are actually found elsewhere in the world," he says. "And in as unlikely places as cat pee and human sweat, for example." © 2020 npr

Keyword: Chemical Senses (Smell & Taste)
Link ID: 27583 - Posted: 11.16.2020

By Jonathan Lambert Octopus arms have minds of their own. Each of these eight supple yet powerful limbs can explore the seafloor in search of prey, snatching crabs from hiding spots without direction from the octopus’ brain. But how each arm can tell what it’s grasping has remained a mystery. Now, researchers have identified specialized cells not seen in other animals that allow octopuses to “taste” with their arms. Embedded in the suckers, these cells enable the arms to do double duty of touch and taste by detecting chemicals produced by many aquatic creatures. This may help an arm quickly distinguish food from rocks or poisonous prey, Harvard University molecular biologist Nicholas Bellono and his colleagues report online October 29 in Cell. The findings provide another clue about the unique evolutionary path octopuses have taken toward intelligence. Instead of being concentrated in the brain, two-thirds of the nerve cells in an octopus are distributed among the arms, allowing the flexible appendages to operate semi-independently (SN: 4/16/15). “There was a huge gap in knowledge of how octopus [arms] actually collect information about their environment,” says Tamar Gutnick, a neurobiologist who studies octopuses at Hebrew University of Jerusalem who was not involved in the study. “We’ve known that [octopuses] taste by touch, but knowing it and understanding how it’s actually working is a very different thing.” Working out the specifics of how arms sense and process information is crucial for understanding octopus intelligence, she says. “It’s really exciting to see someone taking a comprehensive look at the cell types involved,” and how they work. © Society for Science & the Public 2000–2020

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 27560 - Posted: 10.31.2020

By Lucy Hicks Ogre-faced spiders might be an arachnophobe’s worst nightmare. The enormous eyes that give them their name allow them to see 2000 times better than we can at night. And these creepy crawlers are lightning-fast predators, snatching prey in a fraction of a second with mini, mobile nets. Now, new research suggests these arachnids use their legs not only to scuttle around, but also to hear. In light of their excellent eyesight, this auditory skill “is a surprise,” says George Uetz, who studies the behavioral ecology of spiders at the University of Cincinnati and wasn’t involved in the new research. Spiders don’t have ears—generally a prerequisite for hearing. So, despite the vibration-sensing hairs and receptors on most arachnids’ legs, scientists long thought spiders couldn’t hear sound as it traveled through the air, but instead felt vibrations through surfaces. The first clue they might be wrong was a 2016 study that found that a species of jumping spider can sense vibrations in the air from sound waves. Enter the ogre-faced spider. Rather than build a web and wait for their prey, these fearsome hunters “take a much more active role,” says Jay Stafstrom, a sensory ecologist at Cornell University. The palm-size spiders hang upside down from small plants on a silk line and create a miniweb across their four front legs, which they use as a net to catch their next meal. The spiders either lunge at bugs wandering below or flip backward to ensnare flying insects’ midair. © 2020 American Association for the Advancement of Science.

Keyword: Hearing; Evolution
Link ID: 27559 - Posted: 10.31.2020

By Nicholas Bakalar Long-term exposure to noise may be linked to an increased risk for Alzheimer’s disease and other forms of dementia. Researchers did periodic interviews with 5,227 people 65 and older participating in a study on aging. They assessed them with standard tests of orientation, memory and language, and tracked average daytime noise levels in their neighborhoods for the five years preceding the cognitive assessments. About 11 percent had Alzheimer’s disease, and 30 percent had mild cognitive impairment, which often progresses to full-blown dementia. Residential noise levels varied widely, from 51 to 78 decibels, or from the level of a relatively quiet suburban neighborhood to that of an urban setting near a busy highway. The study is in Alzheimer’s & Dementia. After controlling for education, race, smoking, alcohol consumption, neighborhood air pollution levels and other factors, they found that each 10 decibel increase in community noise level was associated with a 36 percent higher likelihood of mild cognitive impairment, and a 29 percent increased risk for Alzheimer’s disease. The associations were strongest in poorer neighborhoods, which also had higher noise levels. The reasons for the connection are unknown, but the lead author, Jennifer Weuve, an associate professor of epidemiology at Boston University, suggested that excessive noise can cause sleep deprivation, hearing loss, increased heart rate, constriction of the blood vessels and elevated blood pressure, all of which are associated with an increased risk for dementia. © 2020 The New York Times Company

Keyword: Alzheimers; Hearing
Link ID: 27551 - Posted: 10.28.2020

By Stephani Sutherland Many of the symptoms experienced by people infected with SARS-CoV-2 involve the nervous system. Patients complain of headaches, muscle and joint pain, fatigue and “brain fog,” or loss of taste and smell—all of which can last from weeks to months after infection. In severe cases, COVID-19 can also lead to encephalitis or stroke. The virus has undeniable neurological effects. But the way it actually affects nerve cells still remains a bit of a mystery. Can immune system activation alone produce symptoms? Or does the novel coronavirus directly attack the nervous system? Some studies—including a recent preprint paper examining mouse and human brain tissue—show evidence that SARS-CoV-2 can get into nerve cells and the brain. The question remains as to whether it does so routinely or only in the most severe cases. Once the immune system kicks into overdrive, the effects can be far-ranging, even leading immune cells to invade the brain, where they can wreak havoc. Some neurological symptoms are far less serious yet seem, if anything, more perplexing. One symptom—or set of symptoms—that illustrates this puzzle and has gained increasing attention is an imprecise diagnosis called “brain fog.” Even after their main symptoms have abated, it is not uncommon for COVID-19 patients to experience memory loss, confusion and other mental fuzziness. What underlies these experiences is still unclear, although they may also stem from the body-wide inflammation that can go along with COVID-19. Many people, however, develop fatigue and brain fog that lasts for months even after a mild case that does not spur the immune system to rage out of control. Another widespread symptom called anosmia, or loss of smell, might also originate from changes that happen without nerves themselves getting infected. Olfactory neurons, the cells that transmit odors to the brain, lack the primary docking site, or receptor, for SARS-CoV-2, and they do not seem to get infected. Researchers are still investigating how loss of smell might result from an interaction between the virus and another receptor on the olfactory neurons or from its contact with nonnerve cells that line the nose. © 2020 Scientific American,

Keyword: Learning & Memory; Chemical Senses (Smell & Taste)
Link ID: 27547 - Posted: 10.24.2020

Frank R. Lin, M.D., Ph.D. When I was going through my otolaryngology residency at Johns Hopkins in the early 2000s, I was struck by the disparity between how hearing loss was managed in children and in older adults. In the case of the child, it was a medical priority to ensure access to a hearing aid so he or she could communicate optimally at home and in school, and such devices were covered by insurance. This approach was justified based on extensive research demonstrating that hearing loss could have a substantial impact on a child’s cognitive and brain development, with lifetime consequences for educational and vocational achievement. For the older adult, the approach was radically different, even if the degree of hearing impairment was the same as in the child. The adult would be reassured that the deficit was to be expected, based on his or her age, and told that a hearing aid, if desired, would represent an out-of-pocket expense averaging about $4,000. Medicare provided no coverage for hearing aids. There was no robust research demonstrating meaningful consequences of hearing loss for older adults, as there was for children, and the clinical approach was typically guided by the notion that it was a very common, and hence inconsequential, aspect of aging. But this approach didn’t make sense, given what I had observed clinically. Older adults with hearing loss recounted to me their sense of isolation and loneliness, and the mental fatigue of constantly concentrating in trying to follow conversations. Family members would often describe a decline in patients’ general well-being and mental acuity as they struggled to hear. For those who obtained effective treatment for their hearing loss with hearing aids or a cochlear implant, the effects were often equally dramatic. Patients spoke of reengaging with family, no longer getting fatigued from straining to listen, and becoming their “old selves” again. If hearing was fundamentally important for children and represented a critical sensory input that could affect brain function, wouldn’t loss of hearing have corresponding implications for the aging brain and its function? © 2020 The Dana Foundation.

Keyword: Hearing; Alzheimers
Link ID: 27525 - Posted: 10.16.2020

By Katherine J. Wu Researchers in Iceland have identified a new mutant superpower — but the genetic trait probably won’t be granting anyone admission to the X-Men. A small contingent of the world’s population carries a mutation that makes them immune to the odious funk that wafts off fish, according to a study of some 11,000 people published Thursday in the journal Current Biology. The trait is rare, but potent: When faced with a synthetic odor that would put many people off their lunch, some test subjects smelled only the pleasant aroma of caramel, potato or rose. The vast majority of people aren’t so lucky. Nearly 98 percent of Icelanders, the research said, are probably as put off by the scent as you’d expect. The mutation is thought to be even rarer in populations in other countries. “I can assure you I do not have this mutation,” said Dr. Kári Stefánsson, a neurologist and the study’s senior author. “I tend to get nauseated when I get close to fish that is not completely fresh.” Dr. Stefánsson is the founder and chief executive of deCODE genetics, a biopharmaceutical company in Iceland’s capital, Reykjavik, which has been parsing the human genome for several decades. The team’s latest caper involved a deep dive into the underappreciated sense of olfaction. Study participants were asked to take a whiff of six Sniffin’ Sticks — pens imbued with synthetic odors resembling the recognizable scents of cinnamon, peppermint, banana, licorice, lemon and fish. They were asked to identify the smell, then rate its intensity and pleasantness. The older the study subjects were, the more they struggled to accurately pinpoint the scents. That’s unsurprising, given that sensory functions tend to decline later in life, said Rósa Gísladóttir, the study’s lead author. But even younger people didn’t always hit the mark, she said. The lemon and banana sticks, for instance, prompted descriptions of gummy bears and other candy-sweet smells. © 2020 The New York Times Company

Keyword: Chemical Senses (Smell & Taste); Genes & Behavior
Link ID: 27519 - Posted: 10.10.2020

By Cathleen O’Grady Tinnitus—a constant ringing or buzzing in the ears that affects about 15% of people—is difficult to understand and even harder to treat. Now, scientists have shown shocking the tongue—combined with a carefully designed sound program—can reduce symptoms of the disorder, not just while patients are being treated, but up to 1 year later. It’s “really important” work, says Christopher Cederroth, a neurobiologist at the University of Nottingham, University Park, who was not involved with the study. The finding, he says, joins other research that has shown “bimodal” stimulation—which uses sound alongside some kind of gentle electrical shock—can help the brain discipline misbehaving neurons. Hubert Lim, a biomedical engineer at the University of Minnesota, Twin Cities, hit on the role of the tongue in tinnitus by accident. A few years ago, he experimented with using a technique called deep brain stimulation to restore his patients’ hearing. When he inserted a pencil-size rod covered in electrodes directly into the brains of five patients, some of those electrodes landed slightly outside the target zone—a common problem with deep brain stimulation, Lim says. Later, when he started up the device to map out its effects on the brain, a patient who had been bothered by ringing ears for many years, said, “Oh, my tinnitus! I can’t hear my tinnitus,” Lim recalls. With certain kinds of tinnitus, people hear real sounds. For instance, there might be repeated muscular contractions in the ear, Lim says. But for many people, it’s the brain that’s to blame, perceiving sounds that aren’t there. One potential explanation for the effect is that hearing loss causes the brain to overcompensate for the frequencies it can no longer hear. © 2020 American Association for the Advancement of Science.

Keyword: Hearing; Attention
Link ID: 27517 - Posted: 10.10.2020

By Ian Randall It’s one of life’s little ironies: Sweet foods get sweeter when you add a little salt. Now, scientists may have provided connoisseurs of salted caramel and grapefruit with the reason this culinary trick is worth its salt. Your ability to savor food comes from the receptor cells in your tongue’s taste buds. Sweet tastes are detected by a family of receptors called T1R, which pick up both natural sugars and artificial sweeteners. Scientists originally thought disabling the T1R family would stop any responses to sweet stimuli. But in 2003, researchers showed that mice whose T1R genes had been genetically “knocked out” still liked the sugar glucose. The finding suggested there must be another way that mice—and possibly humans—sense sweetness. Seeking an explanation, physiologist Keiko Yasumatsu of Tokyo Dental Junior College and colleagues turned to a protein that works with glucose elsewhere in the body: sodium-glucose cotransporter 1 (SGLT1). In the kidneys and intestine, SGLT1 uses sodium to carry glucose into cells to provide them with energy. Curiously, the protein is also found in sweet-responsive taste cells. The researchers rubbed the tongues of unconscious T1R mice with a solution of glucose and salt—which contains the sodium SGLT1 needs to work—and recorded the responses of nerves connected to their taste cells. The salt seemed to make all the difference: It caused the rodents’ nerves to fire more rapidly, compared with mutated mice given only glucose. Conscious mice also seemed to show a preference for the sugar-salt solution. But this only worked with glucose; sweeteners like saccharin didn’t trigger a response. © 2020 American Association for the Advancement of Science.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 27510 - Posted: 10.07.2020

Jon Henley Europe correspondent Four Covid-19 sniffer dogs have begun work at Helsinki airport in a state-funded pilot scheme that Finnish researchers hope will provide a cheap, fast and effective alternative method of testing people for the virus. A dog is capable of detecting the presence of the coronavirus within 10 seconds and the entire process takes less than a minute to complete, according to Anna Hielm-Björkman of the University of Helsinki, who is overseeing the trial. “It’s very promising,” said Hielm-Björkman. “If it works, it could prove a good screening method in other places” such as hospitals, care homes and at sporting and cultural events. After collecting their luggage, arriving international passengers are asked to dab their skin with a wipe. In a separate booth, the beaker containing the wipe is then placed next to others containing different control scents – and the dog starts sniffing. If it indicates it has detected the virus – usually by yelping, pawing or lying down – the passenger is advised to take a free standard polymerase chain reaction (PCR) test, using a nasal swab, to verify the dog’s verdict. In the university’s preliminary tests, dogs – which have been successfully used to detect diseases such as cancer and diabetes – were able to identify the virus with nearly 100% accuracy, even days before before a patient developed symptoms. Scientists are not yet sure what exactly it is that the dogs sniff when they detect the virus. A French study published in June concluded that there was “very high evidence” that the sweat odour of Covid-positive people was different to that of those who did not have the virus, and that dogs could detect that difference. Dogs are also able to identify Covid-19 from a much smaller molecular sample than PCR tests, Helsinki airport said, needing only 10-100 molecules to detect the presence of the virus compared with the 18m needed by laboratory equipment. © 2020 Guardian News & Media Limited

Keyword: Chemical Senses (Smell & Taste)
Link ID: 27490 - Posted: 09.25.2020

Researchers say mother bats use baby talk to communicate with their pups. Experts say that it helps bats learn the language. MARY LOUISE KELLY, HOST: You know how scientists are always curious? Well, one scientist started wondering if bats do something that humans do. AHANA AURORA FERNANDEZ: When we humans talk to a baby, we automatically change our voices. Hello, my baby. You are so cute. My voice goes up. SACHA PFEIFFER, HOST: That's Ahana Aurora Fernandez. She's in Berlin but did her bat study in Panama. And she found that, as many humans do, mommy bats talk to baby bats in a similar way. There's a word for this way of talking. It's motherese (ph). Experts say that in humans - and, apparently, also in bats - it helps with language learning. KELLY: Ahana Fernandez sent us recordings she made to illustrate her findings. They are slowed down so we can better hear the differences between adult bats talking to each other and the motherese used on bat pups. First, here's two adult bats talking to each other. KELLY: OK, and now here's a mother bat with her pup. PFEIFFER: It took patience for Ahana Hernandez to record bat conversation. She sat in the jungle in a chair for hour after hour, waiting for bat conversations to happen. She even brought along books to pass the time. Scientific research is not always riveting. KELLY: No. All told, Ahana Fernandez and her colleagues conducted their research for these last five years, and they found something else along the way. Baby bats babble. FERNANDEZ: They use sort of a vocal practice behavior which is reminiscent of babbling in infants. KELLY: Bat baby talk. PFEIFFER: Her team's report was published this month, and it shows that in the first three months of life, these bat pups experiment with their speech. FERNANDEZ: They learn a part of their adult vocal repertoire through vocal imitation as we humans do. © 2020 npr

Keyword: Animal Communication; Language
Link ID: 27444 - Posted: 09.02.2020

By Jane E. Brody Orthostatic hypotension — to many people those are unfamiliar words for a relatively common but often unrecognized medical problem that can have devastating consequences, especially for older adults. It refers to a brief but precipitous drop in blood pressure that causes lightheadedness or dizziness when standing up after lying down or sitting, and sometimes even after standing, for a prolonged period. The problem is likely to be familiar to people of all ages who may have been confined to bed for a long time by an injury, illness or surgery. It also often occurs during pregnancy. But middle-aged and older adults are most frequently affected. A significant number of falls and fractures, particularly among the elderly, are likely to result from orthostatic hypotension — literally, low blood pressure upon standing. Many an older person has fallen and broken a hip when getting out of bed in the morning or during the night to use the bathroom, precipitating a decline in health and loss of independence as a result of this blood pressure failure. Orthostatic hypotension is also a risk factor for strokes and heart attacks and even motor vehicle accidents. It can be an early warning sign of a serious underlying cardiovascular or neurological disorder, like a heart valve problem, the course of which might be altered if detected soon enough. But as one team of specialists noted, although orthostatic hypotension is a “highly prevalent” disorder, it is “frequently unrecognized until late in the clinical course.” Under normal circumstances, when we stand up, gravity temporarily causes blood to pool in the lower half of the body; then, within 20 or 30 seconds, receptors in the heart and carotid arteries in the neck trigger a compensating mechanism called the baroreflex that raises the heart rate and constricts blood vessels to increase blood pressure and provide the brain with an adequate supply of blood. © 2020 The New York Times Company

Keyword: Stress
Link ID: 27442 - Posted: 09.02.2020

By Carolyn Wilke Taste buds can turn food from mere fuel into a memorable meal. Now researchers have discovered a set of supersensing cells in the taste buds of mice that can detect four of the five flavors that the buds recognize. Bitter, sweet, sour and umami — these cells can catch them all. That’s a surprise because it’s commonly thought that taste cells are very specific, detecting just one or two flavors. Some known taste cells respond to only one compound, for instance, detecting sweet sucralose or bitter caffeine. But the new results suggest that a far more complicated process is at work. When neurophysiologist Debarghya Dutta Banik and colleagues turned off the sensing abilities of more specific taste cells in mice, the researchers were startled to find other cells responding to flavors. Pulling those cells out of the rodents’ taste buds and giving them a taste of several compounds revealed a group of cells that can sense multiple chemicals across different taste classes, the team reports August 13 in PLOS Genetics. “We never expected that any population of [taste] cells would respond to so many different compounds,” says Dutta Banik, of the Indiana University School of Medicine in Indianapolis. But taste cells don’t respond to flavors in insolation; the brain and the tongue work together as tastemakers (SN: 11/24/15). So the scientists monitored the brain to see if it received bitter, sweet or umami signals when mice lacked a key protein needed for these broadly tasting cells to relay information. Those observations revealed that without the protein, the brain didn’t get the flavor messages, which was also shown when mice slurped bitter solutions as though they were water even though the rodents hate bitter tastes, says Dutta Banik, who did the work at the University at Buffalo in New York. © Society for Science & the Public 2000–2020.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 27419 - Posted: 08.15.2020