Alex Smith remembers the nights that permanently changed what he hears. A punk and metal fan, he has attended lots of noisy concerts over the years. One band, My Bloody Valentine, is known for playing an incredibly loud chord and “holding it for like 18 minutes,” says Smith. Shortly after he graduated from college, he left one of their shows, as he’d left many others — with his ears clicking. The annoying sensation was gone a few mornings later. But some time later he woke up with a squeaky noise in his right ear. This persistent sound resembled “someone releasing air from a balloon,” says Smith. That was in 1999.
He still hears the annoying sound. It has never gone away!
Smith is one of an estimated 50 million Americans with a condition called persistent tinnitus. Tinnitus (TIN-ih-tus) is a constant ringing, hissing or buzzing in the ears. It can be temporary, lasting only for a few hours or days. Or it can persist for years — even a lifetime. Smith had temporary tinnitus on and off for years. Until it became permanent.
Some medicines and medical disorders can trigger persistent tinnitus. So can inner-ear damage from loud noise. Once considered an ailment of older people, tinnitus now afflicts many kids as young as 11. Risky listening behaviors tend to be the cause in such young patients.
They expose their ears to loud music at concerts, clubs and through gaming and listening devices. As a result, a new study shows, more than one in four of them may now hear a nonstop ringing or other noise. The study also suggests that persistent tinnitus in teens may warn of serious hearing damage that could worsen as the victim gets older.
This information is new, the researchers reported June 6 in Scientific Reports. Until now, the problem has largely been hidden — unrecognized by even hearing specialists, they note.
Tinnitus in teens and preteens, and the hidden damage it may point to, are “a major public health challenge,” notes Larry Roberts of McMaster University in Ontario, Canada. A neuroscientist, he’s one of the study’s authors. Those sounds that never go away can interfere with studying and sleeping. They can make it hard to hear someone talking in a crowded room. Some teens with tinnitus say it makes them feel irritated, depressed or isolated from their friends. The sounds may sometimes disappear for a time. But often they return — permanently!
Study detects a hidden danger
Tanit Ganz Sanchez led the new study. She’s an otolaryngologist (OH-toh-lair-in-GOLL-oh-gist) — a doctor who specializes in diseases of the ears, nose and throat. She works at the University of São Paolo School of Medicine in Brazil. She, Roberts and their colleagues worked there with 170 teens and preteens who were attending a local private school in Brazil. The researchers asked the students about both their listening habits and any symptoms of tinnitus.
The team also tested the students’ hearing and tolerance for loud noises. To do this, they placed each student in a soundproof chamber. Then they cranked up the volume on certain sounds until the student said the level had become uncomfortable. This was judged to be their sound level tolerance. Other studies have verified tinnitus in teens with written surveys, says Roberts. But this was the first, he says, to also test kids’ hearing in this type of acoustic chamber.
The team also tested the health of each student’s outer and inner hair cells. These are tiny structures within the cochlea (KOKE-lee-uh). It's an organ within the inner ear. The hair cells' role is to pick up sound vibrations and then send that information on to the brain. Outer hair cells help increase the sensitivity of vibrations that the inner hair cells detect.
The researchers tested these hair cells in two ways. First, they created an audiogram, a graphic display of how loud a sound had to be for a teen to hear it. The second technique placed a small microphone inside the ear. It measured the very weak sounds emitted by a healthy ear. Hearing specialists refer to these as otoacoustic (OH-toh-uh-KOOS-tik) emissions.
All 170 students had healthy outer and inner hair cells, the measurements showed. And all could hear speech and typical classroom sounds well.
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But more than half of the students reported they’d had at least one temporary bout of tinnitus within the last year. In about half of the studied students, the unwanted sounds disappeared within a few hours or days. But almost one-third of all students in this study reported a nonstop ringing in their ears! These students also proved abnormally sensitive to loud noises.
What this means
Says Roberts, the reduced sound level tolerance in these teens could signal damage to the cochlea in the places where inner hair cells connect to the auditory nerves. The nerves carry impulses from each ear to the brain.
At the end of each of these nerves is a synapse. It’s where a nerve cell’s ending (called a dendrite) sits ready to receive information. In the ear, the hair cells send a chemical signal — or message. When the nerve cell’s dendrite receives that chemical message, it translates it into an electrical impulse. It then sends that impulse to the brain, signaling that a particular sound has been detected.
But loud sounds can damage hair cells. This may cause them to stop working, even die. Gradually, the nerves may die, too. Such damage cannot be repaired. And it gets worse over time — eventually leading to some loss of hearing.
Research by others has shown that tinnitus tends to occur in people with a history of exposure to loud sounds. But in his study, Roberts notes, all of the young students had equally risky listening behaviors. They all exposed themselves to loud sounds by turning up the volume of music played through their headphones. And they did not wear ear protection at raves, clubs and concerts.
So why were only some students plagued by that never-ending ringing in their ears? Roberts now suspects that some people’s ears simply may be especially vulnerable to loud sounds. For now, he says, there’s no way to know who those people will be — until their symptoms show up.
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The sounds of Tinnitus:
Tinnitus can take different forms, including a ringing, buzzing, or hissing sound in a person’s ears.
This audio sample is what a hissing tinnitus might sound like.
This audio sample is what a ringing tinnitus might sound like.
This audio sample is what a tinnitus tone might sound like.
All sounds courtesy of HNP Lab at McMaster University.
None of the students with persistent tinnitus in this study had been diagnosed before they took part. Their increased sound level intolerance also had gone unrecognized.
This doesn’t surprise Norma Mraz. She’s a pediatric audiologist in Alpharetta, Ga. “A lot of times, kids have had tinnitus so long it seems normal to them,” she says. “Or their parents don’t take it seriously when they say, ‘I have a weird sound in my ear.’ Tinnitus just isn’t thoroughly reported.”
Most teens that Mraz sees in her practice come in for reasons other than tinnitus. Unless she specifically asks, they might never tell her they have it.
Audiologists normally test hearing with audiograms. These only measure damage to the sturdy auditory nerve fibers that transmit low sounds. Tinnitus, by contrast, comes from damage to the delicate auditory nerve fibers that transmit high sounds. In the São Paolo study, only the sound level tolerance test accurately identified students reporting tinnitus. Audiologists don’t use this to test for tinnitus, notes Mraz.
Even when someone can still hear outside sounds well, the impacts of any tinnitus can be intense. Paul Wallfisch knows firsthand. He’s a keyboardist with the poundingly loud band Swans. He says his tinnitus can make him feel “edgy” and “hollow.”
Eugene Ferrari is a drummer with The Unband. He’s toured with metal acts like Dio, Anthrax and Def Leppard. When asked what his tinnitus sounds like, he hums a high-pitched tone. It’s like the leaky, squeaky balloon sound Alex Smith hears. For others, they don’t hear a ringing sound so much as a chorus of chirping crickets. And one 10-year-old in Mraz’s practice describes her tinnitus as sounding like “wind beating on leaves.”
Ferrari’s tinnitus interferes with his ability to understand people in noisy places. He’s coped by learning to read lips. That’s the only way he can keep up with conversations.
“All your social skills start to be impacted by tinnitus,” Mraz points out. “It affects family, friends — everything.”
There isn’t a cure for persistent tinnitus. Hearing specialists mostly teach people how to cope with the condition. Mraz usually teaches her patients what she refers to as “retraining” therapy. It requires that they learn to “tune out” their inner sounds. But, she asks, “If you knew you could prevent it, wouldn’t you choose to do just that?”
Prevention is high on Roberts’ mind, too. “Two percent of people with tinnitus are so disturbed by it that their quality of life collapses,” he says. “Everyone else learns to function. But if someone called and said, ‘I have a treatment that’ll get rid of it,’ they’d take it.” Roberts should know. This scientist got his tinnitus from cutting the grass with a loud power mower — and not wearing earplugs.
The number one piece of advice Roberts and Mraz offer for preventing tinnitus is for people to revise their listening habits. If you go to a concert or are doing some other very loud activity (such as using a power mower, being around loud engines or visiting a shooting range), always wear earplugs. You can even have custom earplugs made to cut down on noise.
If the noise about you is louder than you can stand, leave. When you’re listening to music through headphones or ear buds, make sure you can hear someone talking to you from a meter away.
And take note: If you’ve already experienced temporary tinnitus, that’s a sign you may be on the path to worse damage. This could lead to nonstop noise — and even deafness to certain sound levels or pitches. The only clear way to avoid this fate? Follow the advice outlined above. Then do it forever!
acoustic Having to do with sound or hearing.
acoustic chamber A room that blocks out all outside sounds. This allows hearing specialists to control precisely what sounds — and their volume — someone inside the chamber is exposed to.
audiology The field of science and medicine concerned with hearing. An audiologist is a health care professional who works in this field.
audiogram A hearing test that shows, via a graph, whether a person has suffered hearing loss, and how much.
auditory An adjective referring to something that can be heard or that has to do with the process of hearing.
auditory cortex A part of the brain in humans and other animals that processes sound.
auditory nerve The nerve that carries electrical signals that represent sound from the ear to the brain.
cochlea (plural cochleae) A spiral-shaped structure in the inner ear of humans and other mammals. The natural battery in the mammalian inner ear provides power to drive signals from the ear to the brain. Those signals travel along the auditory nerve.
hair cells The sensory receptors inside the ears of vertebrates that allows them to hear. These actually resemble stubby hairs.
neuroscientist Someone who studies the structure or function of the brain and other parts of the nervous system.
hearing impairment An inability to fully receive sounds through the ear. This can be mild, moderate or severe. Someone with a hearing impairment may use specialized equipment, such as a hearing aid or a cochlear implant, to improve their hearing.
otolaryngology A medical specialty for physicians who specialize in diseases of the ears, nose and throat. A doctor who works in this field is known as an otolaryngologist.
pediatrics A field of medicine that has to do with children and especially child health. A doctor who works in this field is known as a pediatrician.
psychology (adj. psychological) The study of the human mind, especially in relation to actions and behavior. To do this, some perform research using animals. Scientists and mental-health professionals who work in this field are known as psychologists.
sound level tolerance The level of loudness that someone can tolerate well. It is tested in a sound-proof booth by an audiologist who plays different pitches at different levels until a patient reports being able to listen to these comfortably.
synapse The junction between neurons that transmits chemical and electrical signals.
tinnitus An uncontrolled and non-stop ringing or buzzing in the ears, usually triggered by tissue damage from exposure to loud noise. It can be short-lived, lasting hours or a day. In some instances, however, people may experience it for years or decades.
Journal: T. Ganz Sanchez et al. Tinnitus is associated with reduced sound level tolerance in adolescents with normal audiograms and otoacoustic emissions. Scientific Reports. Published online June 6, 2016. doi: 10.1038/srep27109.