Category: Tinnitus

PORTLAND, Ore. — Every minute of every day, Bill McClellan hears an incessant hissing or ringing noise that fluctuates between a faint low-pitched static to a piercing high-pitched ring.

If he manages to fall asleep amid the cacophony, he awakens a few hours later to the same intolerable din. His resulting sleep deprivation makes it difficult to concentrate and his attention span is short. He can't stand to drive because the whine of his tires on the highway synchronizes with the ringing in his ears, creating an unbearable racket in his head.

McClellan, 53, of Chehalis, Wash., is one of 40 million Americans with tinnitus, a perception of sound with no external source that only the sufferer can hear. For 2 1/2 years McClellan repeatedly sought help for his tinnitus, but was consistently told nothing could be done.

"An audiologist and several clinics all told me the same thing: 'Go home; nothing can be done; it will only get worse as you get older.' Tinnitus is the most frustrating thing I've ever had to deal with in my life. It's claustrophobic. At times the ringing is so bad, I don't want to go on."

Unfortunately, McClellan's experience is typical of most patients with chronic tinnitus, according to Robert Folmer, Ph.D., a clinical neurophysiologist in the Oregon Health & Science University Tinnitus Clinic, OHSU Oregon Hearing Research Center.

"For years patients have been told, 'Nothing can be done for tinnitus, so you just have to live with it.' When patients hear these words, it's like hitting a brick wall. What are they supposed to do next? They're left with little or no hope," said Folmer. "Even though there is no cure for many cases of tinnitus, clinicians can help patients obtain relief from the symptom now with proven tinnitus management strategies."

To help clinicians identify, treat and help patients manage this debilitating condition, Folmer, along with colleagues William H. Martin, Ph.D., and Yong-Bing Shi, M.D., Ph.D., recently published research findings and practice recommendations in an article featured on the cover of the July 2004 issue of the Journal of Family Practice.

In the article, the researchers provide detailed evaluation and treatment guidelines for physicians who might otherwise send patients home with no hope. They write that in some cases, underlying conditions — infections, high blood pressure, hypothyroidism, diabetes or autoimmune disorders — contribute to tinnitus and may be treated with medication, thereby resolving the problem. There are medications, they explain, known to be ototoxic, or damaging to the ear, which also may exacerbate tinnitus, such as some chemotherapy agents, diuretics, anticonvulsants or medications containing a large amount of quinine. When possible, patients should be given alternative medications that do not contribute to hearing loss or tinnitus, they write.

If no treatable underlying cause of tinnitus is found, the researchers advise physicians to start a comprehensive tinnitus management program. For patients like McClellan, who has severe chronic tinnitus — lasting six months or longer and having a significant impact on one's ability to enjoy life — the researchers recommend a number of proven tinnitus management therapies, individualized to meet each patient's needs.

Among the recommended options is acoustic therapy. Patients listen to "pleasant sounds" such as music, relaxation CDs or a tabletop sound machine in any environment that is too quiet. For those who experience chronic insomnia with their tinnitus, a tabletop sound machine connected to a pillow embedded with speakers may provide relief. In-the-ear sound generators that produce broadband sounds like rain or a distant waterfall to muffle or mask tinnitus can be worn during the day. Patients with significant hearing loss often benefit from wearing hearing aids. Hearing aids will sharpen patients' hearing and also decrease their perception of tinnitus.

In addition to tinnitus management, Folmer and his colleagues are at the forefront in tinnitus research. At present they are working on two tinnitus research projects: one involving the use of functional MRI to identify brain activity associated with tinnitus perception and suppression, and another using transcranial magnetic stimulation for tinnitus suppression.

"The goal is not necessarily to mask or remove the patient's perception of tinnitus," Folmer said. "In many cases that's not possible. We want patients to pay less attention to their tinnitus, so we help them to understand and gain control of it until it's no longer a negative factor in their lives."

McClellan, a microscope salesman, first learned of the OHSU Tinnitus Clinic from a friend who works at OHSU. He immediately made an appointment. As a result, for the first time since being diagnosed, he has achieved relief.

"At the clinic I learned that it's all linked," he said. "I wasn't getting enough rest at night because my tinnitus woke me up at 2 or 3 in the morning, so they recommended I take Ambien. Now I take Ambien at 10 and I'm sound asleep until 6. With adequate sleep, the ringing isn't so bad. They also told me my blood pressure was up, a contributing factor to tinnitus, and recommended I have my heart meds increased, and I have. The clinic revealed the things I should be doing."

McClellan also has purchased two custom-made in-the-ear sound generators, but says it's too early to tell whether they will provide him with long-term relief from tinnitus.

###

OHSU Tinnitus Clinic

The OHSU Tinnitus Clinic was the first medical clinic in the world established to help tinnitus patients, and it is one of the few full-time tinnitus clinics in the country. More than 8,000 patients from every state and some from around the world have been treated at the clinic since its inception in the 1970s. For more information, visit http://www.ohsu.edu/ohrc/tinnitusclinic.

Particulars

Robert Folmer, Ph.D., is an associate professor of otolaryngology/head and neck surgery, OHSU School of Medicine; and a clinical neurophysiologist, OHSU Tinnitus Clinic, OHSU Oregon Hearing Research Center.

William Martin, Ph.D., is a professor of otolaryngology/head and neck surgery, OHSU School of Medicine; and multi-program director of the OHSU Tinnitus Clinic, OHSU Oregon Hearing Research Center.

Yong-Bing Shi, M.D., Ph.D., is an assistant professor of otolaryngology/head and neck surgery, OHSU School of Medicine; and medical director of the OHSU Tinnitus Clinic and the Northwest Center for Voice and Swallowing.

— New research suggests that years of repeated exposure to loud noise increases the risk of developing a non-cancerous tumor that could cause hearing loss.

“It doesn't matter if the noise comes from years of on-the-job exposure or from a source that isn't job-related,” said Colin Edwards, a doctoral student in the School of Public Health at Ohio State University.

In the current study, people who were repeatedly exposed to loud noise over the span of several years were on average one-and-a-half times as likely to develop this type of tumor compared to people who weren't exposed to such noise on a regular basis.

The tumor, called acoustic neuroma, grows slowly and symptoms typically become noticeable around age 50 or older. Of the 146 people with acoustic neuroma in this study, nearly two out of three were 50 or older.

An acoustic neuroma tumor slowly presses the cranial nerve that is responsible for sensing sound and helping with balance. Symptoms include hearing loss and a constant ringing in the ears, or tinnitus.

The study is currently in the online advance access edition of the American Journal of Epidemiology. The study will also appear in the February 15 printed edition of the same journal.

Edwards and his colleagues gathered four years of data from the Swedish portion of the INTERPHONE Study, an international study of cell phone use and tumors that affect the brain and head.

The researchers used the Swedish portion of the study because health officials there keep meticulous data on rates of acoustic neuroma development in the country's population, said Judith Schwartzbaum, a study co-author and an associate professor of epidemiology in the School of Public Health at Ohio State .

In addition to the 146 study participants with acoustic neuroma, another 564 people without the tumor who served as controls were also interviewed by a nurse. The participants in this group were randomly selected from the continuously updated Swedish population registry. Study participants ranged in age from 20 to 69.

All participants were asked if they were regularly exposed to occupational and non-occupational loud noise and, if so, for how many years. “Loud noise” was defined as at least 80 decibels – the sound of city traffic.

If the subjects said that they had been regularly exposed to loud noise, they were then asked to describe the activities during which they were exposed to that noise.

Categories for loud noise exposure included: exposure to machines, power tools and/or construction noise; exposure to motors, including airplanes; exposure to loud music, including employment in the music industry; and exposure to screaming children, sports events and/or restaurants or bars.

The researchers also collected data on the use of hearing protection.

The two types of loud noise posing the highest risk of acoustic neuroma development were exposure to machines, power tools and/or construction (1.8 times more likely to develop the tumor) and exposure to music, including employment in the music industry (2.25 times more likely to develop the tumor.)

Exposure to motors, including airplanes increased acoustic neuroma risk by 1.3 times, while regular exposure to screaming children, sports events and/or bars and restaurants increased the risk by 1.4 times.

The number of years that a person was exposed to any category of loud noise also contributed to the development of acoustic neuroma. Just five years of regular exposure to loud noise increased the chance that a person would develop acoustic neuroma by one-and-a-half times.

“It's not surprising that the longer that people are exposed to loud noise, the greater their chances become for developing the tumor,” Edwards said.

The study results also suggest the importance of wearing ear protection when exposed to loud noises. People who reported that they protected their ears from loud noise had about the same risk of developing acoustic neuroma as people who were not exposed to loud noise. People who protected their hearing were also half as likely to develop acoustic neuroma as people who didn't wear ear protection.

The tumor is fairly rare, accounting for only about 6 to 10 percent of tumors that develop inside the skull. Depending on the population, anywhere from one to 20 people per 100,000 develop acoustic neuroma each year. The people with the tumor in this study had the most common type – unilateral acoustic neuroma. About 95 percent of all cases of acoustic neuroma affect only one ear. The other kind, bilateral acoustic neuroma, is inherited and affects both ears.

If the tumor is caught early enough through a thorough examination and hearing tests, a physician may be able to surgically remove it. But as the tumor grows larger, it may become attached to the nerves that control facial movement, balance and hearing, making it far more difficult to remove the entire tumor.

Edwards and Schwartzbaum conducted the study with researchers from the Institute of Environmental Medicine of the Karolinska Institutet in Stockholm, Sweden.

Funding for this work was provided by the European Union Fifth Framework Program; the Swedish Research Council; and the International Union Against Cancer.

After 36 years in private dental practice, Fred Kreutzer, D.M.D., began struggling to hear. It's been five years since he retired from his practice and Kreutzer now wears hearing aids in both ears. Although he has a family history of hearing loss, he believes the high-speed tools he worked with eight hours a day for so many years may have played a role in his hearing troubles.

"I think if you listen to any high-pitched noise for any length of time, it will get to you eventually," said Kreutzer, an assistant professor in operative dentistry at the OHSU School of Dentistry. "But in my case, with a family history of hearing loss, it may be hereditary, as well."

Whether high-speed dental tools contribute to long-term hearing loss is the subject of a study currently under way in the OHSU Tinnitus Clinic and the School of Dentistry. According to Robert Folmer, Ph.D., one of the study leaders, published research is mixed about whether high-speed dental tools contribute to noise-induced hearing loss over time.

"Over the years, we have seen dentists in the OHSU Tinnitus Clinic who were convinced that long-term exposure to sound from high-speed hand pieces contributed to their high-frequency hearing loss and tinnitus," said Folmer. "These anecdotes, in combination with the research being divided about high-speed hand pieces playing a role in hearing loss, prompted our study. We hope the study is a good first step toward scientific evidence behind the anecdotes we've been hearing." Fulmer is associate professor of otolaryngology/head and neck surgery, School of Medicine, and chief of clinical services at the OHSU Tinnitus Clinic, Oregon Hearing Research Center.

Tinnitus, or ringing of the ears, can be constant or intermittent and can include buzzing, hissing or sizzling sounds. Many people experience momentary tinnitus, a high-pitched tone that lasts up to 30 seconds. Acute tinnitus, however, can last days or weeks and is most commonly caused by exposure to loud noise such as music at a rock concert, power tools or gunfire. The subsequent ringing indicates damage to the tiny hair-like structures within the inner ear and if exposure to loud noise continues, permanent hearing loss is likely.

Most of the current high-speed hand pieces, such as high-speed drills and scalers used by dental professionals, are between 90 to 100 decibels, says Folmer. That's the equivalent of a gas lawnmower or other power tools, which are loud enough to cause hearing loss over time. And hand pieces have actually gotten "quieter" over the years with the advent of modern technologies. However, very few dental professionals or students interviewed for the study so far, wear earplugs to protect themselves from this noise.

None of the 54 dental schools nationally are known to require dental students to wear ear protection while treating patients.

School of Dentistry Dean Jack Clinton, D.M.D., welcomed Folmer's study. "Any research that can help us keep students healthy and safe is a top priority," said Clinton. "We hope just the fact that the study is being done will continue to help raise awareness within the dental school about the possible hearing loss from high-speed dental instruments so dental professionals can make good decisions as they go through their careers."

Folmer is conducting his research this summer with Clackamas High School senior April Kaelin, a student he is mentoring through Portland State University's Apprenticeships in Science and Engineering (ASE) program. Folmer and April are investigating noise-induced hearing loss by conducting hearing tests with a portable audiometer, examining ear canals with an otoscope and asking participants to answer questions about occupational and recreational noise exposure. They also have measured the sound levels of different hand pieces while they're used on patients.

"We want to compare the hearing tests of dentists, dental assistants, and dental hygienists to those of dental students and people of comparable age in other professions," said Folmer. "We also want to examine whether there's a correlation between hearing thresholds and the amount of time that dental professionals are exposed to loud devices at work. And if dental professionals exhibit evidence of noise-induced hearing loss, can it be correlated with occupational or recreational noise exposure? Our hypothesis is that if dental professionals utilize hearing protective devices, they will exhibit less noise-induced hearing loss than dental professionals who do not protect their ears."

Charles (Mark) Malloy, D.M.D., M.S., assistant professor of prosthodontics at the OHSU School of Dentistry, wore ear protection for most of his 21 years of dentistry in the military. "Hearing loss from high-speed hand pieces has been a suggestion in dentistry for as long as I can remember," said Malloy. "My dad was a dentist so I grew up around dentists and there were a lot of them that couldn't hear. It sounds reasonable to me that high-speed hand pieces may contribute to long-term hearing loss." Malloy said he stopped wearing ear protection a decade ago when he joined the School of Dentistry and began seeing patients only one day a week, but the study is making him consider using ear protection again. "Ears are pretty nice!" said Malloy, with a chuckle.

Rita Patterson, D.M.D., an assistant professor of prosthodontics who introduces the hand pieces to first-year students, also is interested in the study. "We tell the students that they can wear earplugs, which are supplied to students as a standard part of their dental equipment. There are times during the course that I teach that we have 75 high-speed hand pieces running at the same time [there are 75 dental students] for more than two hours at a time. Many instructors, including myself, wonder if we have had some hearing loss from the exposure."

So far, about 40 School of Dentistry professionals and students have had their hearing tested and more data is needed before any conclusions can be drawn.

As part of the ASE program, April will present her research August 19 at a PSU symposium.

— Individuals with chronic, moderate tinnitus do more poorly on demanding working memory and attention tests than those without tinnitus, according to research conducted at the University of Western Sydney.

However, on less complex tasks, no significant differences were found, suggesting that tinnitus has no effect on tasks that involve more involuntary, automatic responses.

The study, Tinnitus and Its Effect on Working Memory and Attention, which appeared in the February issue of the 'Journal of Speech, Language, and Hearing Research', adds to the growing body of research on the relationship between tinnitus and cognition, demonstrating an association between tinnitus and reduced cognitive function.

The research has important implications for helping people with tinnitus approach new or difficult tasks that require strategic and conscious control.

"We wanted to learn more about the ways in which chronic tinnitus disrupts cognitive performance," says Susan Rossiter, a former research Masters student at the MARCS Auditory Laboratories at the University's Bankstown Campus.

"Our goal is to use this knowledge to develop management strategies that will help minimize this disruption."

"Ms Rossiter's research project was our first foray into tinnitus," says fellow researcher, Associate Professor Catherine Stevens of the MARCS Auditory Laboratories. She adds, "Our most recent research has also investigated other important variables such as depression and hearing loss."

Dr Gary Walker, Honorary Adjunct Fellow at the MARCS Auditory labs adds, "Our ultimate goal is to use this knowledge to develop management strategies that will help minimize disruption."

Thirty-eight people participated as subjects. Nineteen, who were ages 34-63 years, came from English-speaking backgrounds, and had constant, moderate to severe tinnitus made up the experimental group. The control group also had 19 participants. They matched individuals in the experimental group by age, educational level, occupation, and verbal IQ.

Tinnitus is the perception of sound in the absence of auditory stimulation. Described as a "ringing in the ears" or "buzzing" or "whooshing" sound, it can be temporary, intermittent, or permanent.

Although its exact cause is often unknown, tinnitus can be a symptom of hearing loss, allergies, or exposure to loud noise or ototoxic medicines.

Past research has shown that it can be accompanied by anxiety, insomnia, problems with auditory perception, and poor general and mental health.

The 'Journal of Speech, Language and Hearing Research' is published by the American Speech-Language-Hearing Association. The ASHA is the US professional, scientific, and credentialing association for more than 120,000 audiologists, speech-language pathologists, and speech, language, and hearing scientists.

 Children with cancer who suffer hearing loss due to the toxic effects of chemotherapy might one day be able to get their hearing back through pharmacological and gene therapy, thanks to work done with mouse models at St. Jude Children's Research Hospital. Mice with a variety of genetic mutations that disrupt different parts of the ear will also help scientists understand age-related hearing loss in adults, as well as hearing loss caused by long-term exposure to loud noise, according to the researchers.

The investigators took the first step toward these ambitious goals by identifying 17 families of mice whose offspring carry one or more of a variety of mutations that cause them to lose the ability to hear high-frequency sounds, according to Jian Zuo, Ph.D., associate member of the St. Jude Department of Developmental Neurobiology. Zuo is senior author of a report on this work that appears in the October issue of Hearing Research.

These models will help scientists understand what happens in the ears of children who suffer ototoxicity (toxic damage to the inner ear due to chemotherapy) and eventually, which genes are responsible for that damage. "Our ongoing study of these mouse models will advance understanding of age-related and noise-induced hearing loss in humans–such as long-term exposure to loud music–which are similar to the damage that occurs in children receiving chemotherapy," Zuo said.

The mouse models of hearing loss were produced by the Tennessee Mouse Genome Consortium, a group of institutions across Tennessee that includes universities, several medical research centers and a national laboratory.

The consortium used ENU, a chemical that causes random mutations in sperm of mice that were subsequently mated with females. Offspring of this mating carried mutations in one or more specific spots in their DNA, Zuo explained. The random mutations caused a variety of disruptions of normal functions. However, only some of the mutations were likely to cause hearing loss, and it was not known which mutation each mouse had. Therefore, the St. Jude team screened more than 1,800 mice from 285 families using an auditory brainstem responses test. This test determines whether a particular mouse can respond to high frequencies by recording electrical activity from the hearing nerve and other parts of the brain in response to brief, high-frequency sounds. The team identified 17 families that showed evidence of hearing loss. The investigators then determined the types of ear abnormalities the mice had. The goal was to find the genes involved in different aspects of hearing loss.

"Now that we've identified the various problems in the ear that can contribute to hearing loss in these models, we can work back and look for specific mutations in these animals," Zuo said. "That will let us link specific mutations to specific disruptions in the ear that cause hearing loss. The long-term goal is to try to manipulate or replace those genes in order to overcome those problems."

Individual mutations might disrupt the work of a cascade of genes that cooperate to construct certain nerves or sections of the inner ear that sense sound; that stimulation is then turned into electrical impulses that go to the hearing center of the brain. Understanding how a specific mutation disrupts that cascade might lead to ways to repair the damage, Zuo said.

For example, one type of damage that occurs in children whose hearing is damaged by chemotherapy is loss of hair cells in the inner part of the ear. These cells sprout extremely fine hairs that move in response to sound waves and set up the electrical impulse that goes into the brain. These are the same cells damaged in adults by prolonged exposure to loud noise. "In the future we'd like to be able to prevent the loss of these hair cells or trigger their re-growth with some form of pharmacological or gene therapy intervention," Zuo said.

Other authors of this study include Mohammad Habiby Kermany, Lisan Parker and Yun-Kai Guo (St. Jude); Darla Miller (Oak Ridge National Laboratory; Oak Ridge, Tenn.); and Douglas Swanson, Tai-June Yoo and Dan Goldowitz (University of Tennessee Health Science Center, Memphis). This work was supported in part by the National Institutes of Health, a UNCF/MERCK Postdoctoral Science Research Fellowship and ALSAC.

— During last year's NHL playoffs, Edmonton Oilers' fans tried to earn the title of loudest arena in the game, but new University of Alberta research shows that even a few hours of exposure to that level of noise can be harmful.

Bill Hodgetts from the U of A's Faculty of Rehabilitation Medicine and Dr. Richard Liu, from the Faculty of Medicine and Dentistry measured the noise levels during games three, four and six during the Stanley Cup finals against the Carolina Hurricanes last year. Liu attended the games and wore a noise dosimeter near his ear every second of the entire game. No matter where he went in the building, the dosimeter would sample his noise exposure. The research is published in the current edition of the Canadian Medical Association Journal.

The researchers found that for the levels experienced in game three, it took less than six minutes to reach the maximum allowable daily noise dose. Or everyone at the game received approximately 8100 per cent of their daily noise dose without any hearing protection. "Given the vast numbers of fans that do not wear hearing protection to hockey games, thousands are at risk for hearing damage," said the researchers.

Most people don't consider the risk of excessive noise exposure when participating in leisure activities, say the researchers, even though such noise over a period of a few hours can be harmful. "The risk of hearing loss for those who attend hockey games frequently–season ticket holders, workers in the arena, hockey players themselves–warrants serious consideration," they write in the paper. Even the cheapest foam earplugs would make a difference.

"People's ears will usually recover after one or two exposures but if they're doing it repeatedly, they're likely to have a problem," said Hodgetts, who has a joint appointment with the Craniofacial Osseointegration and Maxillofacial Prosthetic Rehabilitation Unit (COMPRU), at the Misericordia Hospital. "The simplest solution is earplugs and contrary to popular belief, it is easier to communicate in a noisy place when wearing earplugs than without. It's hard for people to believe, but it's true."

The two most common symptoms of excessive noise exposure are hearing loss and tinnitus, both of which can have a significant negative impact on quality of life.

Many toys available this Christmas could damage your child's hearing according to the UK-based charity Deafness Research UK.

Working with researcher Dr. Brad Backus from University College London (UCL), the charity tested the noise levels produced by a selection of toys available to buy this Christmas.

Almost all (14 out of 15) of the toys tested produced noise levels above the recommended safety limit of 85dB(A) when held close to the ear. Half of the toys tested had levels above or very near recommended safety limits when measured at 25cm – about an arm's length away.

The most dangerous toys by far were found to be toy guns. A mechanical toy machine gun, a plastic tommy gun, and a cap gun were tested and all were found to have noise levels that exceed recommended limits, making them the most dangerous toys available on the high street. These guns have the potential to cause serious damage to your child's hearing and could cause instant hearing loss.

The research was commissioned by Deafness Research UK, the country's only charity dedicated to finding new cures, treatments, and technologies for deafness and hearing loss. It was carried out by Dr. Brad Backus, a research fellow at UCL's Ear Institute. 15 noise-emitting toys were tested including those aimed at children from 3 months up to 15 years-old. All the toys tested are available this Christmas and they include bestsellers such as Pixar Cars 'Lightening McQueen', Fireman Sam's Action Jupiter and Tomy's 'Spin n'Sound' remote-controlled car*.

For toys, 85dB(A) is the recommended safety limit for noise exposure, prolonged exposure to anything above this level has the potential to cause damage to hearing. 14 of the 15 toys were found to have average noise levels of between 84dB(A) and 115dB(A) when held close (2.5cm) from the microphone. Only one, a VTECH mobile phone for babies, was found to have a noise level below the safety threshold.

When tested at 25cm, a realistic distance a child would hold the toy during normal play, 8 of the 15 toys had average levels ranging from 81dB(A) to 105dB(A). Laser Command, an electronic phaser game, had a level of 88.6dB(A) while Pixar Cars 'Lightening McQueen' had a level just below the threshold at 82.5dB(A).

How a child plays with a toy can strongly influence the risk to his or her hearing. How far the child holds the toy from their ear and how long and how often the child plays with a toy are the critical factors.

Dr. Brad Backus said: "Children's toys clearly have the potential to do harm to their hearing so it's important that people are aware of the dangers and what to do about them. With most of the toys we tested, apart from the guns, there is a potential for harm but they're safe if used sensibly. With most toys, your child will only damage their hearing if they use them too often and for too long a duration, or if they stick them in their ear."

He continued: "Our advice is pretty simple: don't let your child hold noisy toys too close to their ear and don't let them play with them for more than an hour a day. Most parents probably don't want to listen to these toys for too long anyway!"

Three mechanical toy guns were tested — a machine gun, a tommy gun and a cap gun. These were found to have noise levels between 130db(C) and 143 dB(C) at 2.5cm and of between 120 — 140dB(C) at 25cm from the toy.

Dr. Backus continued: "While many of the toys had noise levels that were loud enough to be of concern, the toy guns we tested were extremely noisy and these are what we're most concerned about. They were so loud that my ears were ringing for a while after the testing. If I had children, I wouldn't give any of these gun-toys to them, and I would recommend that people avoid them. They have the very real potential to cause permanent hearing loss."

How loud is too loud"

Noise is measured in dBA, which is a decibel scale modified to take into account the sensitivity of human ears to different pitches of sound. It is a logarithmic scale, which means that an increase or decrease of 3 dBA represents a doubling or halving of intensity, the energy it contains. So, for example, 73 dBA is twice as intense as 70 dBA. However, due to the way we hear sounds, a person with normal hearing will only think a sound has doubled in loudness when it is ten times more intense. For example: 80dBA will only sound twice as loud as 70dBA despite actually having ten times as much energy! An average conversation will reach around 60 dBA while a busy street can peak at 80 to 90 dBA.

Generally, exposure to sound levels below 80 dBA are unlikely to cause any hearing damage. Prolonged exposure to sounds over 80 dBA can damage your hearing and the risk increases as the sound level increases. So at 140 dBA noise causes immediate injury to almost any unprotected ear.

Although there are laws about acceptable levels of noise in different situations, it is impossible to set an objective noise level that is safe for all. Provided the ear is allowed ample rest afterwards, a level of 80 dBA might be tolerated for up to 8 hours, but increase that level by just 3 dBA and the time is reduced to just 4 hours. By 95 dBA the tolerance is less than 15 minutes. However, no two people will have an identical tolerance to noise. Research suggests that a genetic predisposition towards hearing loss is an important factor.

How the toys were tested: Toys were measured using a Cel 450 handheld recording SPL meter. Measurements were carried out in a medium-sized carpeted room with background levels below 40 dB(A). Each toy was measured at 2 distances: (1) 2.5cm, simulating close to the ear use and (2) 25cm, simulating normal arm length use. Thirty second recordings were made while the toy was activated and the average equivalent dB(A) was measured along with the peak dB(C) level. Since the cap gun only produced impulse sounds, only the peak level dB(C) was recorded for that toy.

Regulations and safety standards for toys British Standards are not compulsory, they're recommendations. The latest British and European Standard for toys (BS EN 71-1:2005) states that:

The noise from a toy held close to the ear should not exceed 80dB(A) for a daily exposure of 8 hours. This equates to approximately 85dB(A) for a normal playtime situation (2.5 hours).

• The peak noise level of any toy except cap guns should not exceed 110dB(C)
• The peak noise level of a cap gun should not exceed 125dB(C)

This Standard also recommends that:

• If the peak noise produced by a toy exceeds 110db(C), the potential danger to hearing shall be drawn to the attention of the user.
• Toys which produce high impulse sound levels, or their packaging, shall carry the following warning: "Warning! Do not use close to the ear! Misuse may cause damage to hearing." For toys using percussion caps add: "Do not fire indoors!" American safety standards are also available.

Clinical characteristics of tinnitus such as duration, consistency and other factors influence the way individuals perceive loudness and annoyance associated with the condition, according to a report in the December issue of Archives of Otolaryngology-Head & Neck Surgery, one of the JAMA/Archives journals.

Tinnitus, a ringing, buzzing or whistling sound in one or both ears occurring without outside stimulus, can be acute or chronic, constant or intermittent. Tinnitus can be due to a medical disease or of unknown origin. According to background information in the article, some patients describe their tinnitus to be louder than most or all environmental sounds and 1 percent to 5 percent report that tinnitus is so troublesome that it interferes with sleep or has led to disability and reduced quality of life.

Wolfgang Hiller, Ph.D., University of Mainz, Germany, and Gerhard Goebel, M.D., from Roseneck Center of Behavioral Medicine, Prien, Germany, analyzed data from a mail survey composed of two parts: a questionnaire to assess perceived annoyance and a comprehensive screening questionnaire that grades loudness. The total of 4,995 individuals who responded had an average age of 56 years and was 42 percent female and 58 percent male.

A total of 4,971 individuals accurately completed the loudness survey. Of these, 407 (8.2 percent) rated their condition as grade I (weak degree of tinnitus loudness), 2,964 (59.6 percent) as grade II (medium degree of tinnitus loudness) and 1,600 (32.2 percent) as grade III (strong degree of tinnitus loudness). Annoyance scores were available for 4,982 people of whom 1,957 (39.2 percent) were categorized as mildly distressed, 1,189 (23.9 percent) as severely distressed and 637 (12.8 percent) as most severely distressed. Most of those with grade I conditions reported mild tinnitus distress, those with grade II conditions were split and approximately two-thirds of those in grade III reported having severe or very severe distress, indicating a moderate correlation between loudness and annoyance.

"In particular, higher levels of severity were found in men, older adults, binaural [in both ears] and centrally perceived tinnitus, increase in tinnitus intensity since onset, sensitivity to loud external noise, continuous tinnitus (as opposed to intermittent tinnitus) and the coexistence of hearing loss, vertigo and hyperacusis [abnormal sensitivity to sounds]," the authors note. However, other factors had an inconsistent influence on loudness and annoyance. The share of individuals who experienced an increase in tinnitus loudness since onset was 35 percent whereas there was no clear increase in tinnitus annoyance in years since onset. The authors believe it is possible that habituation and acceptance of tinnitus increase over time, which is likely to lead to reduced annoyance.

"Although it has been shown that personal distress due to tinnitus is to some degree dependent on primarily psychological factors such as cognitive appraisal or differences in coping behavior, the role of physical, audiologic and medical properties of tinnitus should not be underestimated," the authors conclude. "We need studies that investigate the determinants of tinnitus loudness and annoyance to understand more deeply how patients react to their tinnitus and which factors contribute to the long-term maintenance of distress."

For those who pumped up the volume one too many times, UC Irvine researchers may have found a treatment for the hearing damage loud music can cause.

Fan-Gang Zeng and colleagues have identified an effective way to treat the symptoms of tinnitus, a form of hearing damage typically marked by high-pitched ringing that torments more than 60 million Americans. A low-pitched sound, the researchers discovered, applied by a simple MP3 player suppressed and provided temporary relief from the high-pitch ringing tone associated with the disorder.

Tinnitus is caused by injury, infection or the repeated bombast of loud sound, and can appear in one or both ears. It’s no coincidence that many rock musicians, and their fans, suffer from it. Although known for its high-pitched ringing, tinnitus is an internal noise that varies in its pitch and frequency. Some treatments exist, but none are consistently effective.

Zeng presented his study Feb. 13 at the Middle Winter Research Conference for Otolaryngology in Denver.

“Tinnitus is one of the most common hearing disorders in the world, but very little is understood about why it occurs or how to treat it,” said Zeng, a professor of otolaryngology, biomedical engineering, cognitive sciences, and anatomy and neurobiology. “We are very pleased and surprised by the success of this therapy, and hopefully with further testing it will provide needed relief to the millions who suffer from tinnitus.”

As director of the speech and hearing lab at UCI, Zeng and his team made their discovery while addressing the severe tinnitus of a research subject. The patient uses a cochlear implant to address a constant mid-ranged pitched sound in his injured right ear accented by the periodic piercing of a high-pitched ringing sound ranging between 4,000 and 8,000 hertz in frequency.

At first, Zeng thought of treating the tinnitus with a high-pitched sound, a method called masking that is sometimes used in tinnitus therapy attempts. But he ruled out that option because of the severity of the patient’s tinnitus, so an opposite approach was explored, which provided unexpectedly effective results.

After making many adjustments, the researchers created a low-pitched, pulsing sound – described as a “calming, pleasant tone” of 40 to 100 hertz of frequency – which, when applied to the patient through a regular MP3 player, suppressed the high-pitched ringing after about 90 seconds and provided what the patient described as a high-level of continued relief.

Zeng’s patient programs the low-pitched sound through his cochlear implant, and Zeng is currently studying how to apply this treatment for people who do not use any hearing-aid devices. Since a cochlear implant replaces the damaged mechanism in the ear that stimulates the auditory nerve, Zeng believes that a properly pitched acoustic sound will have the same effect on tinnitus for someone who does not use a hearing device. Dr. Hamid Djalilian, a UCI physician who treats hearing disorders, points out that  a custom sound can be created for the patients, who then can download it into their personal MP3 player and use it when they need relief.

“The treatment, though, does not represent a cure,” Zeng said. “This low-pitch therapeutic approach is only effective while being applied to the ear, after which the ringing can return. But it underscores the need to customize stimulation for tinnitus suppression and suggests that balanced stimulation, rather than masking, is the brain mechanism underlying this surprising finding.”

Qing Tang, Jeff Carroll, Andrew Dimitrijevic and Dr. Arnold Starr of UCI; Leonid Litvak of Advanced Bionics Corp.; and Jannine Larkin and Dr. Nikolas H. Blevins at Stanford University participated in the study, which was supported by the National Institutes of Health.

Psychotherapy may help tinnitus suffers cope with the life disturbances that sometimes accompany their condition, according to a new review of studies.

Tinnitus is a sensation of ringing or other noise when there is no external cause for the sound. A counseling method called cognitive behavioral therapy or CBT seems to amplify patients' quality of life, even when the volume of the noise remains the same.

"It's a way of working on beliefs and changing psychological responses to tinnitus," said lead reviewer Pablo Martinez-Devesa. "Usually you'd assess the patient's feelings and perceptions of tinnitus, then introduce education on the possible causes. Then, through several sessions, you would try to change the attitudes of patients toward the tinnitus."

The review of six small randomized controlled trials gathered data on 285 patients. The article appears in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates research in all aspects of health care. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing trials on a topic.

Tinnitus affects up to 18 percent of people in industrialized countries, according to the review. The vast majority of people with the condition do not seek treatment but cope with the noise inside their head on their own.

But between 0.5 percent and 3 percent of adults with tinnitus have a chronic condition severe enough to impinge on their life. Among these sufferers, sleep disturbances, anxiety and depression are common.

After participating in CBT, tinnitus sufferers reported greater overall satisfaction with their life, compared to a similar group of patients who did not receive CBT treatment, the Cochrane review found.

Cognitive behavioral therapy is used with good success as a treatment for depression. So Martinez-Devesa and his team thought CBT might lift the mood of tinnitus sufferers. "We were expecting, perhaps, to see a bigger improvement on the symptoms of depression, but we didn't find it," he said. Martinez-Devesa said the collected studies included just a small number of people with severe depression, so it may have been difficult to perceive a change in mood.

CBT also failed to produce significant improvements in the subjective [or perceived] volume of tinnitus, the review found.

Tinnitus researcher Robert Folmer said how people react or deal with the perception of sound is what separates a sufferer from someone who is little bothered by tinnitus. Folmer, an associate professor of otolaryngology at Oregon Health and Science University, was not on the Cochrane review team.

Cognitive behavioral therapy, which helps people with life and coping skills, is widely available throughout the United States, but Folmer suspects that few American practitioners are using CBT to treat tinnitus.

"We refer a lot of people for psychological counseling, including CBT, but the problem is we never know what they are going to get when they go there," Folmer said. "When I say CBT that means something different to everyone. There's a wide range of what that could be."

Martinez-Devesa says gold-standard cognitive behavioral therapy would include patient education about the condition. But Folmer said that even without specific knowledge about tinnitus, a CBT provider can still be helpful.

"Even though a therapist doesn't know anything about tinnitus, if they help the patient with co-symptoms, our studies have shown that the severity of tinnitus goes down, if those other factors improve," he said.

Often, doctors are at a loss for ways to effectively treat chronic tinnitus. In those cases, helping someone with related conditions like anxiety or sleeping problems becomes the best solution, Folmer said.

Reference: Martinez-Devesa P, et al. Cognitive behavioural therapy for tinnitus (Review). Cochrane Database of Systematic Reviews 2007, Issue 1.

The Cochrane Collaboration is an international nonprofit, independent organization that produces and disseminates systematic reviews of health care interventions and promotes the search for evidence in the form of clinical trials and other studies of interventions. Visit http://www.cochrane.org for more information.