Chapter 9. Hearing, Balance, Taste, and Smell

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By Meghan Rosen Float like a butterfly, sniff out cancer like a bee? Honeybees can detect the subtle scents of lung cancer in the lab — and even the faint aroma of disease that can waft from a patient’s breath. Inspired by the insects’ exquisite olfactory abilities, scientists hooked the brains of living bees up to electrodes, passed different scents under the insects’ antennae and then recorded their brain signals. “It’s very clear — like day and night — whether [a bee] is responding to a chemical or not,” says Debajit Saha, a neural engineer at Michigan State University in East Lansing. Different odors sparked recognizable brain activity patterns, a kind of neural fingerprint for scent, Saha and colleagues report June 4 in Biosensors and Bioelectronics. One day, he says, doctors might be able to use honeybees in cancer clinics as living sensors for early disease detection. Electronic noses, or e-noses, and other types of mechanical odor-sensing equipment exist, but they’re not exactly the bee’s knees. When it comes to scent, Saha says, “biology has this ability to differentiate between very, very similar mixtures, which no other engineered sensors can do.” Scent is an important part of how many insect species communicate, says chemical ecologist Flora Gouzerh of the French National Research Institute for Sustainable Development in Montpellier. For them, “it’s a language,” she says. The idea that animal senses can get a whiff of disease is nothing new; doctors reported a case of a border collie and a Doberman sniffing out their owner’s melanoma in 1989. More recently, scientists have shown that dogs can detect COVID-19 cases by smelling people’s sweat (SN: 6/1/22). A lot of insects probably have disease-detecting abilities, too, Gouzerh says. Ants, for instance, can be trained to pick out the smell of cancer cells grown in a lab dish. But until now, bees’ abilities haven’t been quite so clear, she says. © Society for Science & the Public 2000–2024.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29372 - Posted: 06.26.2024

By Scott Sayare As a boy, Les Milne carried an air of triumph about him, and an air of sorrow. Les was a particularly promising and energetic young man, an all-Scottish swim champion, head boy at his academy in Dundee, a top student bound for medical school. But when he was young, his father died; his mother was institutionalized with a diagnosis of manic depression, and he and his younger brother were effectively left to fend for themselves. His high school girlfriend, Joy, was drawn to him as much by his sadness as his talents, by his yearning for her care. “We were very, very much in love,” Joy, now a flaxen-haired 72-year-old grandmother, told me recently. In a somewhat less conventional way, she also adored the way Les smelled, and this aroma of salt and musk, accented with a suggestion of leather from the carbolic soap he used at the pool, formed for her a lasting sense of who he was. “It was just him,” Joy said, a steadfast marker of his identity, no less distinctive than his face, his voice, his particular quality of mind. Listen to this article, read by Robert Petkoff Joy’s had always been an unusually sensitive nose, the inheritance, she believes, of her maternal line. Her grandmother was a “hyperosmic,” and she encouraged Joy, as a child, to make the most of her abilities, quizzing her on different varieties of rose, teaching her to distinguish the scent of the petals from the scent of the leaves from the scent of the pistils and stamens. Still, her grandmother did not think odor of any kind to be a polite topic of conversation, and however rich and enjoyable and dense with information the olfactory world might be, she urged her granddaughter to keep her experience of it to herself. Les only learned of Joy’s peculiar nose well after their relationship began, on a trip to the Scandinavian far north. Joy would not stop going on about the creamy odor of the tundra, or what she insisted was the aroma of the cold itself. Joy planned to go off to university in Paris or Rome. Faced with the prospect of tending to his mother alone, however, Les begged her to stay in Scotland. He trained as a doctor, she as a nurse; they married during his residency. He was soon the sort of capable young physician one might hope to meet, a practitioner of uncommon enthusiasm, and shortly after his 30th birthday, he was appointed consultant anesthesiologist at Macclesfield District General Hospital, outside Manchester, in England, the first in his graduating class to make consultant. © 2024 The New York Times Company

Keyword: Parkinsons; Chemical Senses (Smell & Taste)
Link ID: 29363 - Posted: 06.15.2024

Ian Sample Science editor Five children who were born deaf now have hearing in both ears after taking part in an “astounding” gene therapy trial that raises hopes for further treatments. The children were unable to hear because of inherited genetic mutations that disrupt the body’s ability to make a protein needed to ensure auditory signals pass seamlessly from the ear to the brain. Doctors at Fudan University in Shanghai treated the children, aged between one and 11, in both ears in the hope they would gain sufficient 3D hearing to take part in conversations and work out which direction sounds were coming from. Within weeks of receiving the therapy, the children had gained hearing, could locate the sources of sounds, and recognised speech in noisy environments. Two of the children were recorded dancing to music, the researchers reported in Nature Medicine. A child facing away from the camera towards a panel of auditory testing equipment with script in the top left corner Dr Zheng-Yi Chen, a scientist at Massachusetts Eye and Ear, a Harvard teaching hospital in Boston that co-led the trial, said the results were “astounding”, adding that researchers continued to see the children’s hearing ability “dramatically progress”. The therapy uses an inactive virus to smuggle working copies of the affected gene, Otof, into the inner ear. Once inside, cells in the ear use the new genetic material as a template to churn out working copies of the crucial protein, otoferlin. Video footage of the patients shows a two-year-old boy responding to his name three weeks after the treatment and dancing to music after 13 weeks, having shown no response to either before receiving the injections. © 2024 Guardian News & Media Limited

Keyword: Hearing; Genes & Behavior
Link ID: 29347 - Posted: 06.06.2024

By Joanne Silberner Think for a minute about the little bumps on your tongue. You probably saw a diagram of those taste bud arrangements once in a biology textbook — sweet sensors at the tip, salty on either side, sour behind them, bitter in the back. But the idea that specific tastes are confined to certain areas of the tongue is a myth that “persists in the collective consciousness despite decades of research debunking it,” according to a review published this month in The New England Journal of Medicine. Also wrong: the notion that taste is limited to the mouth. The old diagram, which has been used in many textbooks over the years, originated in a study published by David Hanig, a German scientist, in 1901. But the scientist was not suggesting that various tastes are segregated on the tongue. He was actually measuring the sensitivity of different areas, said Paul Breslin, a researcher at Monell Chemical Senses Center in Philadelphia. “What he found was that you could detect things at a lower concentration in one part relative to another,” Dr. Breslin said. The tip of the tongue, for example, is dense with sweet sensors but contains the others as well. The map’s mistakes are easy to confirm. If you place a lemon wedge at the tip of your tongue, it will taste sour, and if you put a bit of honey toward the side, it will be sweet. The perception of taste is a remarkably complex process, starting from that first encounter with the tongue. Taste cells have a variety of sensors that signal the brain when they encounter nutrients or toxins. For some tastes, tiny pores in cell membranes let taste chemicals in. Such taste receptors aren’t limited to the tongue; they are also found in the gastrointestinal tract, liver, pancreas, fat cells, brain, muscle cells, thyroid and lungs. We don’t generally think of these organs as tasting anything, but they use the receptors to pick up the presence of various molecules and metabolize them, said Diego Bohórquez, a self-described gut-brain neuroscientist at Duke University. For example, when the gut notices sugar in food, it tells the brain to alert other organs to get ready for digestion. © 2024 The New York Times Company

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29336 - Posted: 06.02.2024

By Jordan Pearson Engineers and scientists have an enduring fascination with spider silk. Similar to typical worm silk that makes for comfy bedsheets, but much tougher, the material has inspired the invention of lighter and more breathable body armor and materials that could make airplane components stronger without adding weight. Researchers are even using examples drawn from spider webs to design sensitive microphones that can one day be used to treat hearing loss and deafness and to improve other listening devices. Spiders use their webs like enormous external eardrums. A team of scientists from Binghamton University and Cornell University reported in 2022 that webs allow arachnids to detect sound from 10 feet away. When you hear a sound through your ear, what you’re really experiencing are changes in air pressure that cause your eardrum to vibrate. This is how microphones work: by mimicking the human ear and vibrating in response to pressure. Instead of vibrating when hit by a wave of pressure like a stick hitting a drumhead, they move with the flow of the air being displaced. Air is a fluid medium “like honey,” said Ronald Miles, a professor of mechanical engineering at Binghamton. Humans navigate this environment without noticing much resistance, but silk fibers are buffeted about by the velocity of the viscous forces in air. Dr. Miles couldn’t help but wonder if this principle could lead to a new kind of microphone. “Humans are kind of arrogant animals,” he said. “They make devices that work like they do.” But he wondered about building a device to be more like a spider and sense “sound with the motion of the air.” © 2024 The New York Times Company

Keyword: Hearing
Link ID: 29310 - Posted: 05.18.2024

By Jake Buehler Sounding like a toxic moth might keep some beetles safe from hungry bats. When certain tiger beetles hear an echolocating bat draw near, they respond with extremely high-pitched clicks. This acoustic countermeasure is a dead ringer for the noises toxic moths make to signal their nasty taste to bats, researchers report May 15 in Biology Letters. Such sound-based mimicry may be widespread among groups of night-flying insects, the scientists say. At night, bats and bugs are locked in sonic warfare. At least seven major insect groups have ears sensitive to bat echolocation pitches, and many often flee in response. Some moths have sound-absorbent wings and fuzz that impart stealth against bat sonar (SN: 11/14/18). Others use their genitals to make ultrasonic trills — above the range of human hearing — that may startle bats or jam their sonar (SN: 7/3/13). Previous research suggested some tiger beetles — a family of fast-running, often strikingly colored predatory beetles with strong jaws — also make high-pitched clicks as a response to human-made imitations of bat ultrasound. So Harlan Gough, a conservation entomologist now at the U.S. Fish and Wildlife Service in Burbank, Wash., and his colleagues set out to answer why. The researchers collected 19 tiger beetle species from southern Arizona and brought them into the lab. They tethered the insects to a metal rod and prompted them to fly. The team then filmed and recorded audio to see how the beetles responded to playback of a bat clicking sequence that immediately precedes an attack. Right away, seven of these species — all nocturnal fliers — pulled their hard, case-like forewings into the path of their beating hindwings. The resulting collisions made high-pitched clicking noises. © Society for Science & the Public 2000–2024.

Keyword: Hearing; Evolution
Link ID: 29308 - Posted: 05.16.2024

Andrew Gregory Health editor A British toddler has had her hearing restored after becoming the first person in the world to take part in a pioneering gene therapy trial, in a development that doctors say marks a new era in treating deafness. Opal Sandy was born unable to hear anything due to auditory neuropathy, a condition that disrupts nerve impulses travelling from the inner ear to the brain and can be caused by a faulty gene. But after receiving an infusion containing a working copy of the gene during groundbreaking surgery that took just 16 minutes, the 18-month-old can hear almost perfectly and enjoys playing with toy drums. Her parents were left “gobsmacked” when they realised she could hear for the first time after the treatment. “I couldn’t really believe it,” Opal’s mother, Jo Sandy, said. “It was … bonkers.” The girl, from Oxfordshire, was treated at Addenbrooke’s hospital, part of Cambridge university hospitals NHS foundation trust, which is running the Chord trial. More deaf children from the UK, Spain and the US are being recruited to the trial and will all be followed up for five years. Prof Manohar Bance, an ear surgeon at the trust and chief investigator for the trial, said the initial results were “better than I hoped or expected” and could cure patients with this type of deafness. “We have results from [Opal] which are very spectacular – so close to normal hearing restoration. So we do hope it could be a potential cure.” He added: “There’s been so much work, decades of work … to finally see something that actually worked in humans …. It was quite spectacular and a bit awe-inspiring really. It felt very special.” Auditory neuropathy can be caused by a fault in the OTOF gene, which makes a protein called otoferlin. This enables cells in the ear to communicate with the hearing nerve. To overcome the fault, the new therapy from biotech firm Regeneron sends a working copy of the gene to the ear. © 2024 Guardian News & Media Limited

Keyword: Hearing; Genes & Behavior
Link ID: 29300 - Posted: 05.09.2024

By Gina Kolata At 7 p.m. on May 7, 1824, Ludwig van Beethoven, then 53, strode onto the stage of the magnificent Theater am Kärntnertor in Vienna to help conduct the world premiere of his Ninth Symphony, the last he would ever complete. That performance, whose 200th anniversary is on Tuesday, was unforgettable in many ways. But it was marked by an incident at the start of the second movement that revealed to the audience of about 1,800 people how deaf the revered composer had become. Ted Albrecht, a professor emeritus of musicology at Kent State University in Ohio and author of a recent book on the Ninth Symphony, described the scene. The movement began with loud kettledrums, and the crowd cheered wildly. But Beethoven was oblivious to the applause and his music. He stood with his back to the audience, beating time. At that moment, a soloist grasped his sleeve and turned him around to see the raucous adulation he could not hear. It was one more humiliation for a composer who had been mortified by his deafness since he had begun to lose his hearing in his twenties. But why had he gone deaf? And why was he plagued by unrelenting abdominal cramps, flatulence and diarrhea? A cottage industry of fans and experts has debated various theories. Was it Paget’s disease of bone, which in the skull can affect hearing? Did irritable bowel syndrome cause his gastrointestinal problems? Or might he have had syphilis, pancreatitis, diabetes or renal papillary necrosis, a kidney disease? After 200 years, a discovery of toxic substances in locks of the composer’s hair may finally solve the mystery. © 2024 The New York Times Company

Keyword: Hearing; Neurotoxins
Link ID: 29293 - Posted: 05.07.2024

By Laura Sanders What does it feel like to be a rat? We will never know, but some very unusual mice may now have an inkling. In a series of new experiments, bits of rat brain grew inside the brains of mice. Donor stem cells from rats formed elaborate — and functional — neural structures in mice’s brains, despite being from a completely different species, researchers report in two papers published April 25 in Cell. The findings are “remarkable,” says Afsaneh Gaillard, a neuroscientist at INSERM and the University of Poitiers in France. “The ability to generate specific neuronal cells that can successfully integrate into the brain may provide a solution for treating a variety of brain diseases associated with neuronal loss.” These chimeric mice are helping to reveal just how flexible brain development can be (SN: 3/29/23). And while no one is suggesting that human brains could be grown in another animal, the results may help clarify biological details relevant to interspecies organ transplants, the researchers say. The success of these rat-mouse hybrids depended on timing: The rat and mouse cells had to grow into brains together from a very young stage. Stem cells from rats that had the potential to mature into several different cell types were injected into mouse embryos. From there, these rat cells developed alongside mice cells in the growing brain, though researchers couldn’t control exactly where the rat cells ended up. In one set of experiments, researchers first cleared the way for these rat cells to develop in the young mouse brains. Stem cell biologist Jun Wu and colleagues used a form of the genetic tool CRISPR to inactivate a mouse gene that instructs their brain cells to build a forebrain, a large region involved in learning, remembering and sensing the world. This left the mice without forebrains — normally, a lethal problem. © Society for Science & the Public 2000–2024.

Keyword: Development of the Brain; Neurogenesis
Link ID: 29274 - Posted: 04.26.2024

Sofia Quaglia Noise pollution from traffic stunts growth in baby birds, even while inside the egg, research has found. Unhatched birds and hatchlings that are exposed to noise from city traffic experience long-term negative effects on their health, growth and reproduction, the study found. “Sound has a much stronger and more direct impact on bird development than we knew before,” said Dr Mylene Mariette, a bird communication expert at Deakin University in Australia and a co-author of the study, published in the journal Science. “It would be wise to work more to reduce noise pollution.” A growing body of research has suggested that noise pollution causes stress to birds and makes communication harder for them. But whether birds are already distressed at a young age because they are affected by noise, or by how noise disrupts their environment and parental care, was still unclear. Mariette’s team routinely exposed zebra finch eggs for five days to either silence, soothing playbacks of zebra finch songs, or recordings of city traffic noises such as revving motors and cars driving past. They did the same with newborn chicks for about four hours a night for up to 13 nights, without exposing the birds’ parents to the sounds. They noticed that the bird eggs were almost 20% less likely to hatch if exposed to traffic noise. The chicks that did hatch were more than 10% smaller and almost 15% lighter than the other hatchlings. When the team ran analyses on their red blood cells and their telomeres – a piece of DNA that shortens with stress and age – they were more eroded and shorter than their counterparts’. The effects continued even after the chicks were no longer exposed to noise pollution, and carried over into their reproductive age four years later. The birds disturbed by noise during the early stages of their lives produced fewer than half as many offspring as their counterparts. © 2024 Guardian News & Media Limited

Keyword: Hearing; Development of the Brain
Link ID: 29273 - Posted: 04.26.2024

By Gillian Dohrn No one wants to eat when they have an upset stomach. To pinpoint exactly where in the brain this distaste for eating originates, scientists studied nauseated mice. The work, published in Cell Reports on 27 March1, describes a previously uncharacterized cluster of brain cells that fire when a mouse is made to feel nauseous, but don’t fire when the mouse is simply full. This suggests that responses to satiety and nausea are governed by separate brain circuits. “With artificial activation of this neuron, the mouse just doesn’t eat, even if it is super hungry,” says Wenyu Ding at the Max Planck Institute for Biological Intelligence in Martinsried, Germany, who led the study. Ding and colleagues suspected that this group of neurons was involved in processing negative experiences, such as feeling queasy, so they injected the mice with a chemical that induces nausea and then scanned the animals’ brains. This confirmed that the neurons are active when mice feel nauseous. Using a light-based technique called optogenetics, the team artificially activated the neurons of mice that had been deprived of food in the hours before the experiment. When the neurons were ‘off’, the mice ate. When the researchers turned them on, the mice walked away mid-chow. These brain cells could influence how fast you eat — and when you stop Researchers also blocked the activity of these neurons in nauseated mice that were hungry and found that the mice overcame their nausea to eat. © 2024 Springer Nature Limited

Keyword: Obesity; Chemical Senses (Smell & Taste)
Link ID: 29263 - Posted: 04.20.2024

Allison Aubrey Imagine if every moment is filled with a high-pitched buzz or ring that you can't turn off. More than 25 million adults in the U.S., have a condition called tinnitus, according to the American Tinnitus Association. It can be stressful, even panic-inducing and difficult to manage. Dozens of factors can contribute to the onset of tinnitus, including hearing loss, exposure to loud noise or a viral illness. There's no cure, but there are a range of strategies to reduce the symptoms and make it less bothersome, including hearing aids, mindfulness therapy, and one newer option – a device approved by the FDA to treat tinnitus using electrical stimulation of the tongue. The device has helped Victoria Banks, a singer and songwriter in Nashville, Tenn., who developed tinnitus about three years ago. "The noise in my head felt like a bunch of cicadas," Banks says. "It was terrifying." The buzz made it difficult for her to sing and listen to music. "It can be absolutely debilitating," she says. Banks tried taking dietary supplements, but those didn't help. She also stepped up exercise, but that didn't bring relief either. Then she read about a device called Lenire, which was approved by the FDA in March 2023. It includes a plastic mouthpiece with stainless steel electrodes that electrically stimulate the tongue. It is the first device of its kind to be approved for tinnitus. "This had worked for other people, and I thought I'm willing to try anything at this point," Banks recalls. She sought out audiologist Brian Fligor, who treats severe cases of tinnitus in the Boston area. Fligor was impressed by the results of a clinical trial that found 84% of participants who tried Lenire experienced a significant reduction in symptoms. He became one of the first providers in the U.S. to use the device with his patients. Fligor also served on an advisory panel assembled by the company who developed it. © 2024 npr

Keyword: Hearing
Link ID: 29259 - Posted: 04.16.2024

By Lisa Sanders, M.D. “We were thinking about going bowling with the kids tomorrow,” the woman told her 43-year-old brother as they settled into their accustomed spots in the living room of their mother’s home in Chicago. It was late — nearly midnight — and he had arrived from Michigan to spend the days between Christmas and New Year’s with this part of his family. She and her husband and her brother grew up together and spent many late nights laughing and talking. She knew her brother was passionate about bowling. He had spent almost every day in his local alley two summers ago. So she was taken by surprise when he answered, “I can’t do that anymore.” Certainly, her brother had had a tough year. It seemed to start with his terrible heartburn. For most of his life, he had what he described as run-of-the-mill heartburn, usually triggered by eating late at night, and he would have to take a couple of antacid tablets. But that year his heartburn went ballistic. His mouth always tasted like metal. And the reflux of food back up the esophagus would get so bad that it would make him vomit. Nothing seemed to help. He quit drinking coffee. Quit drinking alcohol. Stopped eating spicy foods. He told his doctor, who started him on a medication known as a proton pump inhibitor (P.P.I.) to reduce the acid or excess protons his stomach made. That pill provided relief from the burning pain. But he still had the metallic taste in his mouth, still felt sick after eating. He still vomited several times a week. When he discovered that he wouldn’t throw up when he drank smoothies, he almost completely gave up solid foods. When he was still feeling awful after weeks on the P.P.I., his gastroenterologist used a tiny camera to take a look at his esophagus. His stomach looked fine, but the region where the esophagus entered the stomach was a mess. Normally the swallowing tube ends with a tight sphincter that stays closed to protect delicate tissue from the harsh acid of the stomach. It opens when swallowing, to let the food pass. But his swallowing tube was wide open and the tissue around the sphincter was red and swollen. © 2024 The New York Times Company

Keyword: Hearing
Link ID: 29137 - Posted: 02.08.2024

By Gina Kolata Aissam Dam, an 11-year-old boy, grew up in a world of profound silence. He was born deaf and had never heard anything. While living in a poor community in Morocco, he expressed himself with a sign language he invented and had no schooling. Last year, after moving to Spain, his family took him to a hearing specialist, who made a surprising suggestion: Aissam might be eligible for a clinical trial using gene therapy. On Oct. 4, Aissam was treated at the Children’s Hospital of Philadelphia, becoming the first person to get gene therapy in the United States for congenital deafness. The goal was to provide him with hearing, but the researchers had no idea if the treatment would work or, if it did, how much he would hear. The treatment was a success, introducing a child who had known nothing of sound to a new world. “There’s no sound I don’t like,” Aissam said, with the help of interpreters during an interview last week. “They’re all good.” While hundreds of millions of people in the world live with hearing loss that is defined as disabling, Aissam is among those whose deafness is congenital. His is an extremely rare form, caused by a mutation in a single gene, otoferlin. Otoferlin deafness affects about 200,000 people worldwide. The goal of the gene therapy is to replace the mutated otoferlin gene in patients’ ears with a functional gene. Although it will take years for doctors to sign up many more patients — and younger ones — to further test the therapy, researchers said that success for patients like Aissam could lead to gene therapies that target other forms of congenital deafness. © 2024 The New York Times Company

Keyword: Hearing
Link ID: 29119 - Posted: 01.27.2024

By Shaena Montanari Around 2012, Jennifer Groh and her colleagues began a series of experiments investigating the effect of eye movements on auditory signals in the brain. It wasn’t until years later that they noticed something curious in their data: In both an animal model and in people, eye movements coincide with ripples across the eardrum. The finding, published in 2018, seemed “weird,” says Groh, professor of psychology and neuroscience at Duke University — and ripe for further investigation. “You can go your whole career never studying something that is anywhere near as beautifully regular and reproducible,” she says. “Signals that are really robust are unlikely to be just random.” A new experiment from Groh’s lab has now taken her observation a step further and suggests the faint sounds — dubbed “eye movement-related eardrum oscillations,” or EMREOs for short — serve to link two sensory systems. The eardrum oscillations contain “clean and precise” information about the direction of eye movements and, according to Groh’s working hypothesis, help animals connect sound with a visual scene. “The basic problem is that the way we localize visual information and the way we localize sounds leads to two different reference frames,” Groh says. EMREOs, she adds, play a part in relating those frames. The brain, and not the eyes, must generate the oscillations, Groh and her colleagues say, because they happen at the same time as eye movements, or sometimes even before. To learn more about the oscillations, the team placed small microphones in the ears of 10 volunteers, who then performed visual tasks while the researchers tracked their eye movements. The group published their results in Proceedings of the National Academy of Sciences in November. © 2024 Simons Foundation

Keyword: Hearing
Link ID: 29115 - Posted: 01.27.2024

Allison Aubrey Among the roughly 40 million adults in the U.S. who have hearing loss, most don't use hearing aids. This means they may be missing out on more than just good hearing. Research shows hearing loss, if left untreated, can increase the risk of frailty, falls, social isolation, depression and cognitive decline. One study from scientists at Johns Hopkins University found that even people with mild hearing loss doubled their risk of dementia. Now a new study finds that restoring hearing loss with hearing aids may lengthen people's lives. Dr. Janet Choi, an otolaryngologist with Keck Medicine of USC, wanted to evaluate whether restoring hearing with hearing aids may increase the chances of living longer. Using data from the the National Health and Nutrition Examination Survey, a large, national study, Choi and her colleagues tracked the status of nearly 1,900 adults who had been shown to have hearing loss during screenings. The participants completed questionnaires about their use of hearing aids. "The group of patients who were using hearing aids regularly had a 24% lower risk of mortality compared to the group who never use hearing aids," Choi says. Meaning, the participants who were in the habit of wearing hearing aids were significantly less likely to die early. The researchers had hypothesized this would be the case given all the studies pointing to the negative impacts of untreated hearing loss. But Choi says they did not expect such a big difference in mortality risk. "We were surprised," she says. Prior research has shown that age-related hearing loss – if untreated – can take its toll on physical and mental health. And a recent study found restoring hearing with hearing aids may slow cognitive decline among people at high risk. © 2024 npr

Keyword: Hearing
Link ID: 29079 - Posted: 01.06.2024

Rudi Zygadlo To celebrate our anniversary, my partner and I dine in a trendy London restaurant in Hackney with a Michelin star – my first time in such a place. A crispy little bonbon is introduced to us simply as “Pine, kvass lees and vin brûlé.” I watch my partner light up, the flickering candle in her eyes, as the waiter sets the thing down. The impact of the aroma has already registered on her face. With her first bite she is transported to her childhood in Massachusetts. “Gosh,” she gasps, closing her eyes as a New England virgin pine forest explodes in her mind. When she blinks open, returning to the here and now, she looks at me guiltily. I take a bite and wince. No coniferous wonderland for me. Just unpleasant bitterness, confined very much to the tongue. I am pleased for her, truly. I’m a magnanimous guy. But from that moment on, the whole evening is a bit of a spectator sport and, by the end of it, I have a feeling that she is even playing her enjoyment down, muting her reactions, as if to say, “You’re not missing out.” She finds some dishes prove more successful than others – the sweetness of cherry, an umami-rich mushroom – but I am missing out: on the nuances, the emotions, the memories. The smell. It’s been three years since I lost it. November 2020. I was living with three friends in a flat in Glasgow when we all caught Covid in the pre-vaccine days. Two of us lost our smell and never fully recovered it. We’re in good company. Around 700,000 people in the UK are believed to have total smell loss caused by the virus, with around six million still experiencing some olfactory dysfunction. I estimate mine has returned by about 30%, but it’s inconsistent and often distorted. To summarise my symptoms of anosmia, as total or partial loss of smell is known: some things have a faint odour, some don’t smell as they should and others don’t smell at all. For example: basil smells mild but good, ground coffee and a certain brand of toothpaste smell like fish and, mercifully, shit doesn’t stink at all. Apart from the latter, all bad news.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29070 - Posted: 12.31.2023

By Esther Landhuis When Frank Lin was in junior high, his grandma started wearing hearing aids. During dinner conversations, she was often painfully silent, and communicating by phone was nearly impossible. As a kid, Lin imagined “what her life would be like if she wasn’t always struggling to communicate.” It was around that time that Lin became interested in otolaryngology, the study of the ears, nose, and throat. He would go on to study to be an ENT physician, which, he hoped, could equip him to help patients with similar age-related hardships. Those aspirations sharpened during his residency at Johns Hopkins University School of Medicine in the late 2000s. Administering hearing tests in the clinic, Lin noticed that his colleagues had vastly different reactions to the same results in young versus old patients. If mild deficits showed up in a kid, “it would be like, ‘Oh, that hearing is critically important,’” said Lin, who today is the director of the Cochlear Center for Hearing and Public Health at Hopkins. But when they saw that same mild to moderate hearing loss in a 70-something patient, many would downplay the findings. Yet today, research increasingly suggests that untreated hearing loss puts people at higher risk for cognitive decline and dementia. And, unlike during Lin’s early training, many patients can now do something about it: They can assess their own hearing using online tests or mobile phone apps, and purchase over-the-counter hearing aids, which are generally more affordable their predecessors and came under regulation by the Food and Drug Administration in October 2022. Despite this expanded accessibility, interest in direct-to-consumer hearing devices has lagged thus far — in part, experts suggest, due to physician inattention to adult hearing health, inadequate insurance coverage for hearing aids, and lingering stigma around the issue. (As Lin put it: “There’s always been this notion that everyone has it as you get older, how can it be important?”) Even now, hearing tests aren’t necessarily recommended for individuals unless they report a problem.

Keyword: Hearing; Alzheimers
Link ID: 29064 - Posted: 12.27.2023

Alex Johnson The holiday season is upon us, and with it, opportunities to indulge in festive treats. The proverbial saying “you eat with your eyes first” seems particularly relevant at this time of year. The science behind eating behavior, however, reveals that the process of deciding what, when and how much to eat is far more complex than just consuming calories when your body needs fuel. Hunger cues are only part of why people choose to eat. As a scientist interested in the psychology and biology that drives eating behavior, I’m fascinated with how the brain’s experiences with food shape eating decisions. Food-related visual cues can shape feeding behaviors in both people and animals. For example, wrapping food in McDonald’s packaging is sufficient to enhance taste preferences across a range of foods – from chicken nuggets to carrots – in young children. Visual food-related cues, such as presenting a light when food is delivered, can also promote overeating behaviors in animals by overriding energy needs. In fact, a whole host of sensory stimuli – noises, smells and textures – can be associated with the pleasurable consequences of eating and influence food-related decisions. This is why hearing a catchy radio jingle for a food brand, seeing a television ad for a restaurant or walking by your favorite eatery can shape your decision to consume and sometimes overindulge.

Keyword: Obesity; Chemical Senses (Smell & Taste)
Link ID: 29060 - Posted: 12.22.2023

By Carolyn Wilke Newborn bottlenose dolphins sport a row of hairs along the tops of their jaws. But once the animals are weaned, the whiskers fall out. “Everybody thought these structures are vestigial — so without any function,” said Guido Dehnhardt, a marine mammal zoologist at the University of Rostock in Germany. But Dr. Dehnhardt and his colleagues have discovered that the pits left by those hairs can perceive electricity with enough sensitivity that they may help the dolphins snag fish or navigate the ocean. The team reported its findings Thursday in The Journal of Experimental Biology. Dr. Dehnhardt first studied the whisker pits of a different species, the Guiana dolphin. He expected to find the typical structures of hair follicles, but those were missing. Yet the pits were loaded with nerve endings. He and his colleagues realized that the hairless follicles looked like the electricity-sensing structures on sharks and found that one Guiana dolphin responded to electrical signals. They wondered whether other toothed cetaceans, including bottlenose dolphins, could also sense electricity. For the new study, the researchers trained two bottlenose dolphins to rest their jaws, or rostrums, on a platform and swim away anytime they experienced a sensory cue like a sound or a flash of light. If they didn’t detect one of these signals, the dolphins were to stay put. “It’s basically the same as when we go to the doctor’s and do a hearing test — we have to press a button as soon as we hear a sound,” said Tim Hüttner, a biologist at the Nuremberg Zoo in Germany and a study co-author. Once trained, the dolphins also received electrical signals. “The dolphins responded correctly on the first trial,” Dr. Hüttner said. The animals were able to transfer what they had learned, revealing that they could also detect electric fields. Further study showed that the dolphins’ sensitivity to electricity was similar to that of the platypus, which is thought to use its electrical sense for foraging. © 2023 The New York Times Company

Keyword: Hearing
Link ID: 29037 - Posted: 12.09.2023