Links for Keyword: Hearing

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By Barron H. Lerner, M.D. I can’t stand it when someone behind me at a movie chews popcorn with his or her mouth open. I mean, I really can’t stand it. I have misophonia, a condition with which certain sounds can drive someone into a burst of rage or disgust. Although only identified and named in the last 20 years, misophonia has been enthusiastically embraced, with websites, Facebook pages and conferences drawing small armies of frustrated visitors. As a primary care physician, I find that misophonia can present some special challenges: At times, my patients can be the source of annoying sounds. At other times, the condition can be a source of special bonding if I realize that a patient is a fellow sufferer. But some experts question whether misophonia really exists. By naming it, are we giving too much credence to a series of symptoms that are no big deal? Coined by the married researchers Margaret and Pawel Jastreboff of Emory University in 2002, misophonia (“hatred of sound”) is sometimes referred to as selective sound sensitivity syndrome. Like me, those with the disorder identify a series of specific sounds that bother them. A2013 study by Arjan Schröder and his colleagues at the University of Amsterdam identified the most common irritants as eating sounds, including lip smacking and swallowing; breathing sounds, such as nostril noises and sneezing; and hand sounds, such as typing and pen clicking. The range of responses to these noises is broad, from irritation to disgust to anger. Some sufferers even respond with verbal or physical aggression to those making the noises. One woman reported wanting to strangle her boyfriend in response to his chewing. © 2015 The New York Times Company

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 11: Emotions, Aggression, and Stress
Link ID: 20609 - Posted: 02.24.2015

By Warren Cornwall The green wings of the luna moth, with their elegant, long tails, aren’t just about style. New research finds they also help save the insect from becoming a snack for a bat. The fluttering tails appear to create an acoustic signal that is attractive to echolocating bats, causing the predators to zero in on the wings rather than more vital body parts. Scientists pinned down the tails’ lifesaving role by taking 162 moths and plucking the tails off 75 of them. They used fishing line to tether two moths—one with tails, the other without—to the ceiling of a darkened room. Then, they let loose a big brown bat. The bats caught 81% of the tailless moths, but just 35% of those with fully intact wings, they report in a study published online today in the Proceedings of the National Academy of Sciences. High-speed cameras helped show why. In 55% of attacks on moths with tails, the bats went after the tails, often missing the body. It’s the first well-documented example of an organism using body shape to confuse predators that use echolocation, the researchers say—the equivalent of fish and insects that display giant eyespots for visual trickery. © 2015 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20587 - Posted: 02.18.2015

Madeline Bonin Bats and moths have been evolving to one-up each other for 65 million years. Many moths can hear bats’ ultrasonic echolocation calls, making it easy for the insects to avoid this predator. A few species of bat have developed echolocation calls that are outside the range of the moths’ hearing, making it harder for the moths to evade them1. But humans short-circuit this evolutionary arms race every time they turn on a porch light, according to a study in the Journal of Applied Ecology2. In field experiments, ecologist Corneile Minnaar of the University of Pretoria and his colleagues examined the diet of Cape serotine bats (Neoromicia capensis) both in the dark and under artificial light in a national park near Pretoria. The bat, an insect-eating species common in South Africa, has an echolocation call that moths can hear. Minnaar and his team determined both the species and quantity of available insect prey at the test sites using a hand-held net and a stationary trap. Cape serotine bats do not normally eat many moths. As the scientists expected, they caught more during the lighted trials than in the dark. What was surprising, however, was the discovery that the insects formed a greater share of the bats' diet during the lighted trials. The percentage of moths eaten in bright areas was six times larger than in dark zones, even though moths represented a smaller share of the total insect population under the lights than in the shade. But surprisingly, though moths represented a smaller share of the total insect population in the lighted areas, they played a larger role in the bats' diet. © 2015 Nature Publishing Group

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20565 - Posted: 02.09.2015

By Monique Brouillette When the first four-legged creatures emerged from the sea roughly 375 million years ago, the transition was anything but smooth. Not only did they have to adjust to the stress of gravity and the dry environment, but they also had to wait another 100 million years to evolve a fully functional ear. But two new studies show that these creatures weren’t deaf; instead, they may have used their lungs to help them hear. Fish hear easily underwater, as sound travels in a wave of vibration that freely passes into their inner ears. If you put a fish in air, however, the difference in the density of the air and tissue is so great that sound waves will mostly be reflected. The modern ear adapted by channeling sound waves onto an elastic membrane (the eardrum), causing it to vibrate. But without this adaptation, how did the first land animals hear? To answer this question, a team of Danish researchers looked at one of the closest living relatives of early land animals, the African lungfish (Protopterus annectens). As its name suggests, the lungfish is equipped with a pair of air-breathing lungs. But like the first animals to walk on land, it lacks a middle ear. The researchers wanted to determine if the fish could sense sound pressure waves underwater, so they filled a long metal tube with water and placed a loudspeaker at one end. They played sounds into the tube in a range of frequencies and carefully positioned the lungfish in areas of the tube where the sound pressure was high. Monitoring the brain stem and auditory nerve activity in the lungfish, the researchers were surprised to discover that the fish could detect pressure waves in frequencies above 200 Hz. © 2015 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20551 - Posted: 02.05.2015

By ANDREW POLLACK Driving to a meeting in 2008, Jay Lichter, a venture capitalist, suddenly became so dizzy he had to pull over and call a friend to take him to the emergency room. The diagnosis: Ménière’s disease, a disorder of the inner ear characterized by debilitating vertigo, hearing loss and tinnitus, or ringing in the ears. But from adversity can spring opportunity. When Mr. Lichter learned there were no drugs approved to treat Ménière’s, tinnitus or hearing loss, he started a company, Otonomy. It is one of a growing cadre of start-ups pursuing drugs for the ear, an organ once largely neglected by the pharmaceutical industry. Two such companies, Otonomy and Auris Medical, went public in 2014. Big pharmaceutical companies like Pfizer and Roche are also exploring the new frontier. A clinical trial recently began of a gene therapy being developed by Novartis that is aimed at restoring lost hearing. The sudden flurry of activity has not yet produced a drug that improves hearing or silences ringing in the ears, but some companies are reporting hints of promise in early clinical trials. There is a huge need, some experts say. About 48 million Americans have a meaningful hearing loss in at least one ear; 30 million of them have it in both ears, said Dr. Frank R. Lin, an associate professor of otolaryngology and geriatric medicine at Johns Hopkins University. That figure is expected to increase as baby boomers grow older. © 2015 The New York Times Company

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20466 - Posted: 01.10.2015

By Susan Milius In nighttime flying duels, Mexican free-tailed bats make short, wavering sirenlike waaoo-waaoo sounds that jam each other’s sonar. These “amazing aerial battles” mark the first examples of echolocating animals routinely sabotaging the sonar signals of their own kind, says Aaron Corcoran of Wake Forest University in Winston-Salem, N.C. Many bats, like dolphins, several cave-dwelling birds and some other animals, locate prey and landscape features by pinging out sounds and listening for echoes. Some prey, such as tiger moths, detect an incoming attack and make frenzied noises that can jam bat echolocation, Corcoran and his colleagues showed in 2009 (SN: 1/31/09, p. 10). And hawkmoths under attack make squeaks with their genitals in what also may be defensive jamming (SN Online: 7/3/13). But Corcoran didn’t expect bat-on-bat ultrasonic warfare. He was studying moths dodging bats in Arizona’s Chiricahua Mountains when his equipment picked up a feeding buzz high in the night sky. A free-tailed bat was sending faster and faster echolocation calls to refine the target position during the final second of an attack. (Bats, the only mammals known with superfast muscles, can emit more than 150 sounds a second.) Then another free-tailed bat gave a slip-sliding call. Corcoran, in a grad student frenzy of seeing his thesis topic as relevant to everything, thought the call would be a fine way to jam a buzz. “Then I totally told myself that’s impossible — that’s too good to be true.” Five years later he concluded he wasn’t just hearing things. He and William Conner, also of Wake Forest, report in the Nov. 7 Science that the up-and-down call can cut capture success by about 70 percent. Using multiple microphones, he found that one bat jams another, swoops toward the moth and gets jammed itself. © Society for Science & the Public 2000 - 201

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20435 - Posted: 12.20.2014

By recording from the brains of bats as they flew and landed, scientists have found that the animals have a "neural compass" - allowing them to keep track of exactly where and even which way up they are. These head-direction cells track bats in three dimensions as they manoeuvre. The researchers think a similar 3D internal navigation system is likely to be found throughout the animal kingdom. The findings are published in the journal Nature. Lead researcher Arseny Finkelstein, from the Weizmann Institute of Science in Rehovot, Israel, explained that this was the first time measurements had been taken from animals as they had flown around a space in any direction and even carried out their acrobatic upside-down landings. "We're the only lab currently able to conduct wireless recordings in flying animals," he told BBC News. "A tiny device attached to the bats allows us to monitor the activity of single neurons while the animal is freely moving." Decades of study of the brain's internal navigation system garnered three renowned neuroscientists this year's Nobel Prize for physiology and medicine. The research, primarily in rats, revealed how animals had "place" and "grid" cells - essentially building a map in the brain and coding for where on that map an animal was at any time. Mr Finkelstein and his colleagues' work in bats has revealed that their brains also have "pitch" and "roll" cells. These tell the animal whether it is pointing upwards or downwards and whether its head is tilted one way or the other. BBC © 2014

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 13: Memory, Learning, and Development
Link ID: 20393 - Posted: 12.04.2014

By Beth Winegarner When Beth Wankel’s son, Bowie, was a baby, he seemed pretty typical. But his “terrible twos” were more than terrible: In preschool, he would hit and push his classmates to a degree that worried his parents and teachers. As Bowie got a little older, he was able tell his mom why he was so combative. “He would say things like, 'I thought they were going to step on me or push me,’” Wankel said. “He was overly uncomfortable going into smaller spaces; it was just too much for him.” Among other things, he refused to enter the school bathroom if another student was inside. When Bowie was 3, he was formally evaluated by his preschool teachers. They said he appeared to be having trouble processing sensory input, especially when it came to figuring out where his body is in relation to other people and objects. He’s also very sensitive to touch and to the textures of certain foods, said Wankel, who lives with her family in San Francisco. Bowie has a form of what’s known as sensory processing disorder. As the name suggests, children and adults with the disorder have trouble filtering sights, smells, sounds and more from the world around them. While so-called neurotypicals can usually ignore background noise, clothing tags or cluttered visual environments, people with SPD notice all of those and more — and quickly become overwhelmed by the effort. Rachel Schneider, a mental-health expert and a blogger for adults with SPD, describes it as a “neurological traffic jam” or “a soundboard, except the sound technician is terrible at his job.”

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 5: The Sensorimotor System
Link ID: 20391 - Posted: 12.04.2014

By Joyce Cohen Like many people, George Rue loved music. He played guitar in a band. He attended concerts often. In his late 20s, he started feeling a dull ache in his ears after musical events. After a blues concert almost nine years ago, “I left with terrible ear pain and ringing, and my life changed forever,” said Mr. Rue, 45, of Waterford, Conn. He perceived all but the mildest sounds as not just loud, but painful. It hurt to hear. Now, he has constant, burning pain in his ears, along with ringing, or tinnitus, so loud it’s “like a laser beam cutting a sheet of steel.” Everyday noise, like a humming refrigerator, adds a feeling of “needles shooting into my ears,” said Mr. Rue, who avoids social situations and was interviewed by email because talking by phone causes pain. Mr. Rue was given a diagnosis of hyperacusis, a nonspecific term that has assorted definitions, including “sound sensitivity,” “decreased sound tolerance,” and “a loudness tolerance problem.” But hyperacusis sometimes comes with ear pain, too, a poorly understood medical condition that is beginning to receive more serious attention. “This is clearly an emerging field,” said Richard Salvi of the Department of Communicative Disorders and Sciences at the University at Buffalo and a scientific adviser to Hyperacusis Research, a nonprofit group that funds research on the condition. “Further work is required to understand the symptoms, etiology and underlying neural mechanisms.” Loud noises, even when they aren’t painful, can damage both the sensory cells and sensory nerve fibers of the inner ear over time, causing hearing impairment, said M. Charles Liberman, a professor of otology at Harvard Medical School, who heads a hearing research lab at the Massachusetts Eye and Ear Infirmary. And for some people who are susceptible, possibly because of some combination of genes that gives them “tender” ears, noise sets in motion “an anomalous response,” he said. © 2014 The New York Times Company

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20381 - Posted: 12.02.2014

By Sandra G. Boodman ‘That’s it — I’m done,” Rachel Miller proclaimed, the sting of the neurologist’s judgment fresh as she recounted the just-concluded appointment to her husband. Whatever was wrong with her, Miller decided after that 2009 encounter, she was not willing to risk additional humiliation by seeing another doctor who might dismiss her problems as psychosomatic. The Baltimore marketing executive had spent the previous two years trying to figure out what was causing her bizarre symptoms, some of which she knew made her sound delusional. Her eyes felt “weird,” although her vision was 20/20. Normal sounds seemed hugely amplified: at night when she lay in bed, her breathing and heartbeat were deafening. Water pounding on her back in the shower sounded like a roar. She was plagued by dizziness. “I had started to feel like a person in one of those stories where someone has been committed to a mental hospital by mistake or malice and they desperately try to appear sane,” recalled Miller, now 53. She began to wonder if she really was crazy; numerous tests had ruled out a host of possible causes, including a brain tumor. Continuing to look for answers seemed futile, since all the doctors she had seen had failed to come up with anything conclusive. “My attitude was: If it’s something progressive like MS [multiple sclerosis] or ALS [amyotrophic lateral sclerosis], it’ll get bad enough that someone will eventually figure it out.” Figuring it out would take nearly three more years and was partly the result of an oddity that Miller mentioned to another neurologist, after she lifted her moratorium on seeing doctors.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20353 - Posted: 11.25.2014

By Jyoti Madhusoodanan Eurasian jays are tricky thieves. They eavesdrop on the noises that other birds make while hiding food in order to steal the stash later, new research shows. Scientists trying to figure out if the jays (Garrulus glandarius) could remember sounds and make use of the information placed trays of two materials—either sand or gravel—in a spot hidden from a listening jay’s view. Other avian participants of the same species, which were given a nut, cached the treat in one of the two trays. Fifteen minutes later, the listening bird was permitted to hunt up the stash (video). When food lay buried in a less noisy material such as sand, jays searched randomly. But if they heard gravel being tossed around as treats were hidden, they headed to the pebbles to pilfer the goods. Previous studies have shown that jays—like crows, ravens, and other bird burglars that belong to the corvid family—can remember where they saw food being hidden and return to the spot to look for the cache. But these new results, published in Animal Cognition this month, provide the first evidence that these corvids can also recollect sounds to locate and steal stashes of food. In their forest homes, where birds are heard more often than they are seen, this sneaky strategy might give eavesdropping jays a better chance at finding hidden feasts.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20339 - Posted: 11.21.2014

By Abby Phillip You know the ones: They seem to be swaying to their own music or clapping along to a beat only they can hear. You may even think that describes you. The majority of humans, however, do this very well. We clap, dance, march in unison with few problems; that ability is part of what sets us apart from other animals. But it is true that rhythm — specifically, coordinating your movement with something you hear — doesn't come naturally to some people. Those people represent a very small sliver of the population and have a real disorder called "beat deafness." Unfortunately, your difficulty dancing or keeping time in band class probably doesn't quite qualify. A new study by McGill University researchers looked more closely at what might be going on with "beat deaf" individuals, and the findings may shed light on why some people seem to be rhythm masters while others struggle. Truly beat deaf people have a very difficult time clapping or tapping to an auditory beat or swaying to one. It's a problem that is far more severe than a lack of coordination. And it isn't attributable to motor skills, hearing problems or even a person's inability to create a regular rhythm. Illustrating how rare the disorder really is, McGill scientists received hundreds of inquiries from people who thought they were beat deaf, but only two qualified as having truly severe problems.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20304 - Posted: 11.13.2014

by Penny Sarchet It's frustrating when your smartphone loses its signal in the middle of a call or when downloading a webpage. But for bats, a sudden loss of its sonar signal means missing an insect meal in mid-flight. Now there's evidence to suggest that bats are sneakily using sonar jamming techniques to make their fellow hunters miss their tasty targets. Like other bats, the Mexican free-tailed bat uses echolocation to pinpoint prey insects in the dark. But when many bats hunt in the same space, they can interfere with each other's echoes, making detection more difficult. Jamming happens when a sound disrupts a bat's ability to extract location information from the echoes returning from its prey, explains Aaron Corcoran of Johns Hopkins University in Baltimore, Maryland. Previous research has shown that Mexican free-tailed bats can get around this jamming by switching to higher pitches. Using different sound frequencies to map the hunting grounds around them allows many bats to hunt in the same space. In these studies, jamming of each other's signals was seemingly inadvertent – a simple consequence of two bats attempting to echolocate in close proximity. But Corcoran has found evidence of sneakier goings-on. Corcoran has found a second type of sonar jamming in these bats – intentional sabotage of a fellow bat. "In this study, the jamming is on purpose and the jamming signal has been designed by evolution to maximally disrupt the other bat's echolocation," he says. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20288 - Posted: 11.08.2014

By Meredith Levine, Word went round Janice Mackay's quiet neighbourhood that she was hitting the bottle hard. She'd been seen more than once weaving along the sidewalk in front of her suburban home in Pickering, just outside Toronto, in a sad, drunken stagger. But Mackay wasn't drunk. As it turned out, her inner ear, the body's balance centre, had been destroyed by medication when she was hospitalized for over a month back in May 2005. At the time, Mackay was diagnosed with a life-threatening infection in one of her ovaries, and so was put on a cocktail of medication, including an IV drip of gentamicin, a well-known, inexpensive antibiotic that is one of the few that hasn't fallen prey to antibiotic-resistant bacteria. A few weeks later, the infection was almost gone when Mackay, still hospitalized, suddenly developed the bed spins and vomiting. Her medical team told her she'd been laying down too long and gave her Gravol, but the symptoms didn't go away. In a follow-up appointment after her discharge, Mackay was told that the dizziness was a side effect of the gentamicin, and that she would probably have to get used to it. But she didn't discover the extent of the damage until later when neurotologist Dr. John Rutka assessed her condition and concluded that the gentamicin had essentially destroyed her vestibular system, the body's motion detector, located deep within the inner ear. © CBC 2014

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20198 - Posted: 10.13.2014

By Sarah C. P. Williams A wind turbine, a roaring crowd at a football game, a jet engine running full throttle: Each of these things produces sound waves that are well below the frequencies humans can hear. But just because you can’t hear the low-frequency components of these sounds doesn’t mean they have no effect on your ears. Listening to just 90 seconds of low-frequency sound can change the way your inner ear works for minutes after the noise ends, a new study shows. “Low-frequency sound exposure has long been thought to be innocuous, and this study suggests that it’s not,” says audiology researcher Jeffery Lichtenhan of the Washington University School of Medicine in in St. Louis, who was not involved in the new work. Humans can generally sense sounds at frequencies between 20 and 20,000 cycles per second, or hertz (Hz)—although this range shrinks as a person ages. Prolonged exposure to loud noises within the audible range have long been known to cause hearing loss over time. But establishing the effect of sounds with frequencies under about 250 Hz has been harder. Even though they’re above the lower limit of 20 Hz, these low-frequency sounds tend to be either inaudible or barely audible, and people don’t always know when they’re exposed to them. For the new study, neurobiologist Markus Drexl and colleagues at the Ludwig Maximilian University in Munich, Germany, asked 21 volunteers with normal hearing to sit inside soundproof booths and then played a 30-Hz sound for 90 seconds. The deep, vibrating noise, Drexl says, is about what you might hear “if you open your car windows while you’re driving fast down a highway.” Then, they used probes to record the natural activity of the ear after the noise ended, taking advantage of a phenomenon dubbed spontaneous otoacoustic emissions (SOAEs) in which the healthy human ear itself emits faint whistling sounds. © 2014 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20144 - Posted: 10.01.2014

By JOHN ROGERS LOS ANGELES (AP) — The founder of a Los Angeles-based nonprofit that provides free music lessons to low-income students from gang-ridden neighborhoods began to notice several years ago a hopeful sign: Kids were graduating high school and heading off to UCLA, Tulane and other big universities. That’s when Margaret Martin asked how the children in the Harmony Project were beating the odds. Researchers at Northwestern University in Illinois believe that the students’ music training played a role in their educational achievement, helping as Martin noticed 90 percent of them graduate from high school while 50 percent or more didn’t from those same neighborhoods. A two-year study of 44 children in the program shows that the training changes the brain in ways that make it easier for youngsters to process sounds, according to results reported in Tuesday’s edition of The Journal of Neuroscience. That increased ability, the researchers say, is linked directly to improved skills in such subjects as reading and speech. But, there is one catch: People have to actually play an instrument to get smarter. They can’t just crank up the tunes on their iPod. Nina Kraus, the study’s lead researcher and director of Northwestern’s auditory neuroscience laboratory, compared the difference to that of building up one’s body through exercise. ‘‘I like to say to people: You’re not going to get physically fit just watching sports,’’ she said.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 13: Memory, Learning, and Development
Link ID: 20025 - Posted: 09.03.2014

Hearing voices is an experience that is very distressing for many people. Voices – or “auditory verbal hallucinations” – are one of the most common features of schizophrenia and other psychiatric disorders. But for a small minority of people, voice-hearing is a regular part of their lives, an everyday experience that isn’t associated with being unwell. It is only in the past 10 years that we have begun to understand what might be going on in “non-clinical” voice-hearing. Most of what we know comes from a large study conducted by Iris Sommer and colleagues at UMC Utrecht in the Netherlands. In 2006 they launched a nationwide attempt to find people who had heard voices before but didn’t have any sort of psychiatric diagnosis. From an initial response of over 4,000 people, they eventually identified a sample of 103 who heard voices at least once a month, but didn’t have psychosis. Their voice-hearing was also not caused by misuse of drugs or alcohol. Twenty-one of the participants were also given an MRI scan. When this group was compared with voice-hearers who did have psychosis, many of the same brain regions were active for both groups while they were experiencing auditory hallucinations, including the inferior frontal gyrus (involved in speech production) and the superior temporal gyrus (linked to speech perception). Subsequent studies with the same non-clinical voice-hearers have also highlighted differences in brain structure and functional connectivity (the synchronisation between different brain areas) compared with people who don’t hear voices. These results suggest that, on a neural level, the same sort of thing is going on in clinical and non-clinical voice-hearing. We know from first-person reports that the voices themselves can be quite similar, in terms of how loud they are, where they are coming from, and whether they speak in words or sentences. © 2014 Guardian News and Media Limited

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders; Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 19958 - Posted: 08.14.2014

By NICHOLAS BAKALAR A new study reports that caffeine intake is associated with a reduced risk for tinnitus — ringing or buzzing in the ears. Researchers tracked caffeine use and incidents of tinnitus in 65,085 women in the Nurses’ Health Study II. They were 30 to 34 and without tinnitus at the start of the study. Over the next 18 years, 5,289 developed the disorder. The women recorded their use of soda, coffee and tea (caffeinated and not), as well as intake of candy and chocolate, which can contain caffeine. The results appear in the August issue of The American Journal of Medicine. Compared with women who consumed less than 150 milligrams of caffeine a day (roughly the amount in an eight-ounce cup of coffee), those who had 450 to 599 milligrams a day were 15 percent less likely to have tinnitus, and those who consumed 600 milligrams or more were 21 percent less likely. The association persisted after controlling for other hearing problems, hypertension, diabetes, use of anti-inflammatory Nsaid drugs, a history of depression and other factors. Decaffeinated coffee consumption had no effect on tinnitus risk. “We can’t conclude that caffeine is a cure for tinnitus,” said the lead author, Dr. Jordan T. Glicksman, a resident physician at the University of Western Ontario. “But our results should provide some assurance to people who do drink caffeine that it’s reasonable to continue doing so.” © 2014 The New York Times Company

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 19955 - Posted: 08.14.2014

|By Ingrid Wickelgren One important function of your inner ear is stabilizing your vision when your head is turning. When your head turns one way, your vestibular system moves your eyes in the opposite direction so that what you are looking at remains stable. To see for yourself how your inner ears make this adjustment, called the vestibulo-ocular reflex, hold your thumb upright at arm’s length. Shake your head back and forth about twice per second while looking at your thumb. See that your thumb remains in focus. Now create the same relative motion by swinging your arm back and forth about five inches at the same speed. Notice that your thumb is blurry. To see an object clearly, the image must remain stationary on your retina. When your head turns, your vestibular system very rapidly moves your eyes in the opposite direction to create this stability. When the thumb moves, your visual system similarly directs the eyes to follow, but the movement is too slow to track a fast-moving object, causing blur. © 2014 Scientific American

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 7: Vision: From Eye to Brain
Link ID: 19895 - Posted: 07.30.2014

|By James Phillips Our inner ear is a marvel. The labyrinthine vestibular system within it is a delicate, byzantine structure made up of tiny canals, crystals and pouches. When healthy, this system enables us to keep our balance and orient ourselves. Unfortunately, a study in the Archives of Internal Medicine found that 35 percent of adults over age 40 suffer from vestibular dysfunction. A number of treatments are available for vestibular problems. During an acute attack of vertigo, vestibular suppressants and antinausea medications can reduce the sensation of motion as well as nausea and vomiting. Sedatives can help patients sleep and rest. Anti-inflammatory drugs can reduce any damage from acute inflammation and antibiotics can treat an infection. If a structural change in the inner ear has loosened some of its particulate matter—for instance, if otolith (calcareous) crystals, which are normally in tilt-sensitive sacs, end up in the semicircular canals, making the canals tilt-sensitive—simple repositioning exercises in the clinic can shake the loose material, returning it where it belongs. After a successful round of therapy, patients no longer sense that they are tilting whenever they turn their heads. If vertigo is a recurrent problem, injecting certain medications can reduce or eliminate the fluctuating function in the affected ear. As a last resort, a surgeon can effectively destroy the inner ear—either by directly damaging the end organs or by cutting the eighth cranial nerve fibers, which carry vestibular information to the brain. The latter surgery involves removing a portion of the skull and shifting the brain sideways, so it is not for the faint of heart. © 2014 Scientific American

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 19886 - Posted: 07.28.2014