Hearing Aid Blog

How much noise can your ears take?

September 30, 2009

This is a question that OSHA (occupational safety and health administration)  has had to come up with answer to in order to protect workers’ hearing in loud environments (like many factories) from dangerously high noise exposure.

Below is the chart they came up with (this chart assumes the worker is wearing ear plugs and ear muffs):

TABLE G-16 - PERMISSIBLE NOISE EXPOSURES (1)
______________________________________________________________
                            |
  Duration per day, hours   | Sound level dBA slow response
____________________________|_________________________________
                            |
8...........................|                    90
6...........................|                    92
4...........................|                    95
3...........................|                    97
2...........................|                   100
1 1/2 ......................|                   102
1...........................|                   105
1/2 ........................|                   110
1/4  or less................|                   115
____________________________|_______________________________

So, for example, if you work in an environment that is 111dB, you should not be in that environment for more than 1/2 an hour, even with earplugs and muffs on.  Cumulative effects should also be considered.  So if you are in that same environment multiple times per day, there’s a formula that you need to use to figure out what’s legally allowed.  If anyone is interested in the formula you can post a comment, or go to the OSHA website.

Some people are more susceptible to noise damage than others, and certain types of noise (regardless of decibel level) are more likely to hurt your hearing.  Without getting into a lot of detail, some people are less prone to noise damage because of an anti-oxidant effect in their inner ear; some people naturally have more anti-oxidants.  Women, for example have more protection because estrogen is an anti-oxidant, and darker skinned people have more anti-oxidants because they have more melanin.  A natural deduction is that if you load up on a water-soluable anti-oxidant like vitamin C, you’ll have more protection, and studies suggest that that is, in fact, likely.  Although, there are problems with overdosing on vitamin C, so you have to be careful.

With regard to decibel level and damage, studies show something unusual…that if steady-state noise is present before (and during) a loud impact noise, your ears are less likely to be damaged than if that same impact noise was made without having a steady state background noise present beforehand.  Hearing scientist, Don Henderson, coined the phenomenon, the “toughening effect.”

Bottom line here is that you shouldn’t be in noisy situations for too long or it will damage your hearing, and even though there are some things you can do to help prevent it – most obviously – wearing  hearing protection – noise still should be avoided.    When you do where earplugs, it’s good to also wear muffs on top of the plugs to get extra attenuation.

Life of a Hearing Aid

September 18, 2009

It’s surprising that hearing aids don’t need repair or replacement more often.  The electronic components are exposed to heat, perspiration, wax, humidity, rain and daily handling. This can cause parts to wear out, corrode, or lose power.

The life of a hearing aid is usually said to be about 5 years, but can vary from 3-7 depending on a variety of factors.  If you’re thinking about replacing your hearing aids, consider the age of your present aids, improvements in technology, whether your hearing has changed and whther you have a back-up set.  If you have an older hearing aid that needs repair, consider replacing it with an instrument with updated technology.

Feel free to call us if you would like to review the condition of your present aids.  And remember, a cleaning and readjustment of your present hearing aids will often prove significant without the need for new ones.    Our phone number is 301-977-6317.

Cheap Hearing Aids

September 13, 2009

Recent research done at Michigan State University indicated that although consumers with hearing loss might think they are saving significantly more by purchasing inexpensive catalog or over-the-counter hearing aids,  they most likely will be disappointed – or could be taking risks.

There is a high cost variability of hearing aids, and because most consumers do not have or have only partial insurance coverage for hearing aids, people often look for inexpensive options.  Low-cost options are typically marketed on the Internet and in mail-order magazines as listening devices – often for bird watchers or deer hunters.

“These low-cost amplifying devices can look tempting to individuals with hearing impairment because of the significant cost differences,” on researcher, Punch said. “But our research found that the low-cost aids generally don’t meet the fitting requirements to help a hearing-impaired person and could potentially damage a person’s hearing.” 

The research is important to consumers, Callaway says. “Aside from being of extremely poor quality, very low-cost hearing aids (those under $100) have the potential to damage your hearing because they send very loud sounds into the ear.

“Based on the research, the best advice for consumers is to talk to an audiologist. Because hearing aids have complex technical features, they need to be fitted and customized to the individual.” 

The study measured how well the electronic features of the devices could compensate for commonly occurring types of hearing loss, employing methods that audiologists use to fit conventional hearing aids – a process audiologists call prescriptive fitting. Specifically, the researchers found that only a few of the aids they studied met the basic fitting requirements, and, for the few that did, that was true only for a specific degree of hearing loss. 

Although the Food and Drug Administration officially regulates hearing aids, those regulations are not enforced for low-cost amplifying devices that are sold through mail order and on the Internet.

Genetic Hunt turns up Deafness

In genetics, as in life, surprising things can turn up in unexpected places. That was certainly the case when an international group of researchers found three mutations responsible for a form of hereditary deafness in a gene that is implicated in cancer. The research is published in the July 10 issue of The American Journal of Human Genetics.

This surprising finding happened when researchers from the National Institute on Deafness and Other Communication Disorders (NIDCD), National Cancer Institute (NCI), Baylor College of Medicine, Houston, All India Medical Institute in India, and Punjab and Islamabad Universities in Pakistan were scanning the DNA of over a thousand families with deaf children, searching for genes that could be responsible for inherited forms of deafness. Pooling their data, the researchers narrowed the region of one such gene, which they called DFNB39, to a stretch of DNA on chromosome 7.

Genes are segments of DNA that contain the codes for making proteins, which are the building blocks of all the tissues and organs in the body. Nearly all of the human genetic diseases known by scientists are caused by changes in the protein-coding gene sequences in DNA.

However, there are other parts of genes that do not specify the protein’s composition. Instead, these “noncoding” sections regulate the expression of a gene. For example, a regulatory section might turn the gene on or off in one tissue, such as the brain, but not another, such as the heart. Or it might control the timing of the gene’s expression, for example by turning it on only during development or leaving it on all the time. Scientists know much less about these noncoding, regulatory sequences than they do about the protein-coding sequences. As a result, fewer human genetic diseases are known to be associated with such sequences.

When the investigators examined the protein-coding sequences of every gene in the DFNB39 region, they came up short. They could find no protein-coding DNA changes in any of the genes. Thus, they concluded the deafness-causing change had to be in a regulatory section. Exploring further, the scientists found three non-coding mutations in the gene that encodes hepatocyte growth factor, or HGF, which is important for the growth and regeneration of liver tissue.

HGF has also been shown to have different and powerful effects in other tissues. Generally, it influences the production and growth of cells, so many scientists study its effects in cancer, fetal development, and wound repair in adults. Until recently, very few mutations had been found in the HGF gene. Those that were found were in the protein-coding parts of the gene and caused cancer-related diseases. There was no reason to expect that mutations in the HGF gene could cause deafness.

So how do mutations in a gene related to cancer cause deafness?

Often, scientists turn to the mouse as a model organism to study the effects of a gene mutation; however, mice with mutations in the coding sequence of the HGF gene die as embryos. Taking another tack, by looking at mice in which the HGF protein was normal, but over-expressed in all tissues, or under-expressed in just a few tissues including the inner ear, the scientists discovered that the mice survived, but were deaf. This led the researchers to wonder if the DFNB39 mutations caused deafness in humans because of over- or under-expression of HGF.

The group also noted that another mechanism of gene regulation, alternate splicing, was at work in the HGF gene, and was producing alternative forms of the protein-called isoforms. The HGF gene produces five isoforms, and potentially a sixth that the team discovered. The NIDCD-led researchers found that one of the three mutations appears to influence the way the HGF gene chooses between some of the isoforms. The other two mutations in the HGF gene occur in a region that may affect the sixth isoform. Subtle differences in these isoforms could be what drive the development of deafness.

The researchers are now working on a “knock-in” mouse model of DFNB39, in which they will make mutations in the mouse gene that are similar to the regulatory mutations they see in deaf humans. They will use the mice to test their ideas about how regulation of this gene plays a role in hereditary deafness.

Contributors to this research include Drs. Julie Schultz and Robert Morell of NIDCD’s Laboratory of Molecular Genetics, along with lab chief Dr. Thomas Friedman, NCI’s Dr. Glenn Merlino, Dr. Suzanne Leal at Baylor College of Medicine, Dr. Sheikh Riazuddin, of Punjab University, and others.

Taken directly from http://www.nidcd.nih.gov.

FM Systems Overview

September 11, 2009

An FM system is basically a wireless system that allows a hearing aid user to listen to a remote sound source with excellent clarity.  It can be extremely helpful for almost all hearing aid users – especially those with a moderate hearing loss or worse, or people who need to be able to hear at a distance.  It allows for substantial increase in understanding at places like meetings, religious services, noisy places, in the car, hearing people between rooms, or for plays/theatre.  It is great for hearing at a distance, and reducing noise.  You can even plug the device into a computer, stereo, cell phone or TV.

There are a lot of options for FM systems.  There is no one system that is right for everyone.  Each system needs to customized for the patient.    To learn more about FM systems, make an appointment with the audiologist to dsicuss your options.

Hearing Aid Tax credit

September 8, 2009

Last spring, the Hearing Aid Assistance Tax Credit (S 1019) was introduced in the U.S. Senate. If passed, the legislation will allow consumers a tax credit of up to $500 for the purchase of a hearing aid. Senate sponsors Olympia Snowe (R-Maine) and Tom Harkin (D-Iowa) recently cosigned a “Dear Colleague” letter supporting the legislation,  which was referred to the Senate Committee on Finance. Sen. Snowe serves on this committee.

In the U.S. House of Representatives, similar legislation (HR 1646) recently attracted its 100th cosponsor just before the House adjourned for its August recess. In addition, various industry groups hosted events in late August to generate support for the legislation. Attending the events were Dina Titus (D-Nevada) and Ron Kind (D-Wisconsin).

Lyric by Insound

September 3, 2009

There has been a lot of media hype about the Lyric hearing aid.  After a few workshops and speaking with colleagues about their patients’ success with Lyric, we decided to try fitting some devices ourselves at our Chevy Chase location, with some willing patients.  It was a huge success; the feedback we received from our patients convinced us that we made the right decision, so we did more training and expanded the program to our Montgomery Village office.  If you are interested in reading more about how the process of fitting a Lyric instrument works read more here.