Sound Pharmaceuticals (SPI) has received FDA notification that it may proceed with its Phase II study to prevent chemotherapy induced hearing loss. The Ph-II study will enroll 80 patients with advanced head and neck, and non-small cell lung cancer at the National Center for Rehabilitative Auditory Research at the Veterans Administration Hospital and the Oregon Health and Science University in Portland, Oregon.

Hearing loss due to ototoxic medications such as chemotherapy, antibiotics or loop diuretics often results in permanent and progressive disability. Furthermore, the combined use of these ototoxic agents is contraindicated, often limiting their clinical utility. Symptoms of ototoxicity include hearing loss, tinnitus, dizziness, vertigo and difficulty understanding speech.

In several preclinical studies, SPI has showed that its novel chemo-protectant drug product, a small molecule that mimics and induces Glutathione Peroxidase activity was critical in preventing ototoxicity while not interfering with the chemotherapy treatment.

An article on mosquito repellents  published by an English speaking website in Korea, Chosun Ilbo, caught our eye because of a tinnitus-related issue. One of the options discussed used to repel the pesky summertime critters can apparently cause tinnitus.

Electric mats used to keep mosquitoes at bay emit a powerful insecticide (also used in mosquito-aerosols) called pyathroid, which kills the creatures by paralyzing their nervous system. That’s a neat trick except when we learn that they can cause tinnitus, allergic rhinitis, asthma, sneezing, headache,  nausea or in extreme cases coma. Oh and its also rumored to reduce sperm count.

To quote SNL character,  Roseanne Roseannadanna (Gilda Radner), “It just goes to show ya. It’s always somethin’! If it’s not one thing, it’s another!

We couldn’t agree more.

Brent Curtis – Editor

Rock concert goers complaining of ringing in the ears when the show ends may find a solution to the phantom sounds through acupuncture. According to researchers at the University of Michigan (UM), nerves that sense touch in the face and neck might be responsible for the post-concert noises in the head that remain long after the show has ended.

These “touchy” nerves sense the increased activity of the brain when hearing cells are damaged. According to the UM study, “Hyperactivity of these touch-sensing neurons likely plays an important role in tinnitus, often called “ringing in the ears.” While the findings of their research were conducted on animals, the scientists postulate that treatments such as acupuncture targeted on the nerves of the head and neck may provide relief for certain individuals suffering from tinnitus.

In an upcoming issue of Quiet Times Tinnitus Newsletter, tinnitus expert Barry Keate will provide a detailed review of this fascinating new study.

Brent Curtis – Editor

When it comes to hearing in mammals, shape matters. According to a recent study published by the National Institute of Science, there is a direct link between the curvature of the cochlea and its ability to perceive lower frequency hearing limits.

The snail-shaped cochlea located in the inner ear converts sound waves into nerve impulses which are deciphered by the brain. Researchers believe that by understanding this relationship between the shape of the cochlea and its hearing limitations (in mammals) they can estimate what the impact of human activities may have on wild animals (who won’t sit still for a hearing test). The end result could bring greater understanding to how hearing evolved.

The spiral shape of the cochlea is only found in mammals. Those animals with tightly coiled cochleae tend to have greater hearing ranges. Sound enters the ear and strikes the eardrum, which sends vibrations to the fluid of the cochlea. This creates pressure waves that move along a narrowing coiled canal of the cochlea.

According to Darlene Ketten, an assistant professor at Harvard who participated on the study, the curvature of the cochlea and its effect on hearing has long been a controversial subject among scientists. But the new study now provides them with a new theory to better understand the hearing limitations of mammals based on the unique curve of individual cochleae.

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Researchers at the University of Buffalo (UB) are studying to learn if there is a specific area of the brain that is responsible for the sounds associated with tinnitus.

Having studied tinnitus for the past ten years, these scientists will study the brain signals they believe are responsible for creating the phantom sounds of tinnitus. The research uses animal models previously developed at UB. The clinical study is currently being conducted at UB’s Center for Hearing and Deafness under the direction of Richard Salvi, Ph.D.

Dr. Salvi and colleagues found that when the brain’s auditory cortex receives reduced auditory signals from the cochlea (the hearing organ), due to damage or aging, it causes a part of the brain to “turn up the volume,” experience as hissing or ringing. A major goal of the research is to try to identify the neural signature of tinnitus. In other words to find what aberrant pattern of neural activity in the auditory cortex of the brain is associated with the onset of tinnitus.

A study published in The Laryngoscope March of this year by researchers from the Montreal Children’s Hospital (MUHC) showed that certain over-the-counter eardrops for softening earwax can cause severe inflammation and damage to the inner ear and eardrum.

Earwax softeners are used to breakup and disperse excess wax and were created for individuals who complained of discomfort or even deafness from wax buildup blocking their ears.

The research team at MUHC studied the impact of Cerumenex on hearing, overall toxicity in the outer ear and changes in the delicate hair cells of the inner ear in chinchillas. They found harmful effects occurred after only one dose. Based on the well-established animal model which researcher state has a similar hearing mechanism to humans, their finding suggest that Cerumenex has toxic potential and should be used with caution.

While Cerumenex is sold over-the-counter in Canada, it a  prescription is required in the US. The safest course is always to ask your ENT doctor first before using any “over-the-counter” medications that are put directly into your ear.

Hearing health is getting on the government’s radar. Hearing loss and tinnitus are the number one disability experienced by veterans coming out of the Iraq and Afghanistan war. 28 million Americans suffer from some type of hearing loss, and 500,000 to 750,000 Americans have severe to profound hearing impairment or deafness.

Healthy Hearing 2010, part of the NIH’s National Institute on Deafness and Other Communication Disorders is dedicated to helping people improve and protect their hearing health. They have identified eight objectives for reducing the problems caused by hearing loss. The hearing objectives are:

• Increase the number of newborns who get their first hearing test before they’re one month old. Children found to have a hearing loss should get additional testing before they’re three months old, and should be enrolled in rehabilitative services by the time they are six months old.
• Research tells us that babies who are born deaf or hard-of-hearing have a better chance of learning how to use language if the hearing loss is found immediately after they’re born and if they learn a spoken or signed language as early as possible.
• Decrease the number of ear infections in children.
• Ear infections are the number one reason for all doctor and emergency room visits by infants and children. The cost of ear infections to the American public is enormous–roughly $5 billion a year for medical expenses and lost wages. For many children, ear infections tend to occur again and again. When a child has an ear infection, he or she won’t be able to hear clearly, which can interfere with speech and language development.
• Increase the number of deaf or hard-of-hearing people who use rehabilitation services and adaptive devices, such as hearing aids or cochlear implants.
• In today’s world, people must be able to communicate with others as well as understand how to use technology. Technological devices are available now that can help children and adults who are deaf or hard-of-hearing be successful in society and the workplace. In addition, the Individuals with Disabilities Education Act (IDEA) provides technological assistance to deaf and hard-of-hearing infants and older children to help ensure they receive a quality educational experience alongside their hearing peers.
• Increase the number of people who schedule periodic hearing examinations.
• Some forms of hearing loss appear later as a child grows and develops. For this reason, not only should children have their hearing screened at birth, but they should be tested and diagnosed any time a hearing loss is suspected. This is also true for adults. Children also should have their hearing tested before they enter school.
• Increase the number of people who are referred by their doctor for a hearing evaluation and, if needed, treatment.
• The referrals depend on a number of factors, including the type of hearing loss, the age at which hearing loss occurs, the services available in a community, and a family’s preferences.
• Increase the use of ear protection devices and equipment, such as earplugs or earmuffs.
• Noise-induced hearing loss (NIHL) happens when sensitive parts of the inner ear are damaged from being exposed to harmful sounds. The damage is caused by sounds that are too loud, or by loud sounds that are too close or that are heard over a long period of time. NIHL is 100 percent preventable, but once it happens, the hearing loss is permanent. Earplugs and protective earmuffs will protect your hearing when you are exposed to loud noise. NIHL is one of the most common occupational injuries and the second most self-reported type of occupational illness or injury. Industries that have high numbers of workers exposed to NIHL include agriculture, mining, and construction.
• Reduce the number of children, teenagers, and adults suffering from noise-induced hearing loss (objective 7 and 8 combined).
• About 30 million Americans are exposed to dangerous levels of noise every day and 10 million Americans already have hearing loss from noise. Sounds that can cause damage include a chainsaw (110 decibels, or dB), ambulance siren (120 dB), 12-gauge shotgun (165 dB), hair dryer or gas-powered lawn mower (90 dB), and a rock concert or fire-cracker (140 dB). Regular exposure to 110 dB for more than one minute risks permanent hearing loss. More than 15 minutes of unprotected exposure to 100 dB also is damaging. Prolonged exposure to any noise above 85 dB can cause gradual hearing loss. Healthy People 2010 highlights the efforts of WISE EARS! ® , an NIHL prevention and education campaign led by the National Institute on Deafness and Other Communication Disor-ders (NIDCD) in partnership with the National Institute for Occupational Safety and Health (NIOSH).

Summertime and the living is noisy. It is a time for mowing lawns, riding motorcycles, going to rock concerts, and setting off firecrackers. Any of which are capable of causing tinnitus and hearing loss.

According to Andrew Cheng, M.D., an ENT and clinical assistant professor of otolaryngology at New York Medical College, “Noise is probably the most common occupational hazard facing people today, however, outside of work many people participate in recreational activities that can produce harmful noise that can result in tinnitus with repeated exposure.”

Decibels are the unit of measure for noise, rating on a scale from zero to 140; the higher the number of decibels, the louder the noise. “Tinnitus or hearing loss occurs with regular exposure at 110 decibels or more for periods longer than one minute.

Some typical summer sounds and their decibel levels are: mowing the lawn (80-90 decibels); riding motorcycles (110); rock concerts (120); exploding firecrackers (150); watching fireworks (130 to 190).

Protect your hearing by avoiding excessively loud noises when possible — but when exposure to loud noises or activities cannot be avoided you can take a few simple precautions:

• Alternate noisy activities with periods of quiet.
• Use earplugs or other hearing protectors when you know you are going to be exposed to loud noises for long periods of time (like while mowing the lawn or watching your town’s July 4th fireworks display).
• Limit lengthy periods of loud noise exposure, which includes giving your ears a break from iPods and other devices.
• Be a smart consumer: when buying outdoor equipment for the yard, for instance, look for those with the lowest noise levels.

There’s more distressing news concerning the hearing health of young adults… this time from down under. According to a  survey hearing loss and tinnitus among the “IPod” generation is reaching extreme levels.

Apparently more than 70% of young adults in Australia – between 18 and 24 – have tinnitus, or ringing in the ears, which is the first sign of hearing loss. According to a new survey from Australian Hearing, headphones are to blame.

According to News.com.au, Professor Harvey Dillon, director of the National Acoustics Laboratory at Australian Hearing, said that younger respondents had a poor understanding of hearing loss. 25% of them thought that damaged ears would repair themselves and hearing would return.

“Older Australians, I might add, were much wiser, almost none of them thought that,” said Dillon on Fairfax radio.

He said that when people go to noisy parties and concerts the damage happens in two stages – both in the inner ear. One is temporary, one is permanent.

“We tend to notice the temporary loss of hearing and we notice it come back over the next day or two. What we don’t notice is that at the same time, in the same place but through a different mechanism, there’s also a permanent loss going on. A few hair cells dying here, a few hair cells dying there and they add up from time to time.”

According to Dr John D’Arcy, headphones can be used safely. He urges people to set the volume at a level which allows the user to hear someone at arm’s length without them having to shout.

With Senator Edward M. Kennedy’s recent diagnosis of glioma, a malignant brain cancer, the debate about the use of cell phones has been reignited. Last week, three prominent brain surgeons told Larry King on CNN that they do not hold cell phones against their ears.

According to an article in the June 3, 2008 edition of the New York Times Health Section, the three surgeons, Dr. Keith Black of Cedars-Sinai Medical Center in LA, Dr. Vini Khurana at the Australian National University, and Dr. Sanjay Gupta of Emory University and CNN’s Chief Medical Correspondent, all said they either use a headset or use the phone in speaker mode to remove it from their ears and reduce microwave radiation exposure.

CITA, the wireless association’s industry trade group states that “the overwhelming majority of studies…show that wireless phones do not cause a health risk.” However, the FDA has noted that the average period of phone use in the studies was about three years and they don’t address questions about long-term exposure. The studies also did not distinguish between casual and heavy use.

As we have pointed out in a previous article, cell phone use has been associated with acoustic neuroma, a type of brain tumor that causes tinnitus. The other types that are also suspected to be due to cell phone use are glioma, the type Sen. Kennedy developed, and cancer of the parotid, a salivary gland near the ear.

Last year the American Journal of Epidemiology published data from Israel finding a 58% increased risk of Parotid gland tumors among heavy cell phone users. Also, A Swedish analysis of 16 studies in the journal Occupational and Environmental Medicine showed a doubling of risk for acoustic neuroma and glioma after 10 years of heavy cell phone use.

Some doctors say the real concern is not older cell phone users, who began using phones as adults, but children who are beginning to use phones and face a lifetime of exposure. Young people are much more affected. Their brains are growing rapidly and their skulls are thinner.

It is highly advised for all people to use a headset or set the phone on speaker mode. And to restrict cell phone use among young people.

Barry Keate

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