Auris Repletus by Dr. Tom Goyne

Newborn Hearing Screenings

Several times a week, a mother will bring her toddler into my office for a hearing test.  Typically, the mother, nor I, are expecting to find a hearing loss.  By the same token, extraneous circumstances such as a slight delay in speech development dictate that we make sure.

While gathering a case history, the parents will invariably mention to me that, "He/She passed her hearing screening at birth, but we always wondered, how can they tell?  It's not as if he/she was able to respond at just a few days old!"

It's true, other than a startle reflex to very loud sounds, newborns can't respond to sound in a way that we can detect.  But through the application of signal averaging, we can use objective, non-invasive physiologic measures such as otoacoustic emissions (OAE) and auditory evoked potentials (AEP) to determine with relative certainty whether a newborn -- or any other patient incapable of voluntarily responding to stimuli -- has normal hearing or not.

In the case of OAE's sounds are presented to the newborn's ear and if the cochlea is normal sounds will resonate back out.  We record these resonances and if they are a pitch and intensity (right around 0 dB) we expect, we assume normal hearing is present.

AEP's are used more often for newborn screenings because OAE's require the testing to be performed in a quiet setting, and if you have ever been in a hospital's newborn nursery, you know it is not a quiet place.  AEP's on the other hand can be recorded with a fair amount of ambient noise present.  Headphones and sensors are placed on the newborn and electrical signals are painlessly recorded through the newborn's skin [see below].

While these tests are not meant to be a substitute for a comprehensive audiologic examination, performed in a sound-proof booth with a responsive patient, they are reliable and are very good at identifying patients with greater than a mild hearing loss.

Below is a list of states that require newborn hearing screenings, according to the Centers for Disease Control:

Great Advice

Bill Bass, a writer for Men's Journal, interviewed Dr. Craig Kasper, an audiologist with the New York Otolaryngology Group and co-director of the New York Tinnitus Center. about hearing loss and tinnitus -- something Bass himself suffers from.

Kasper is quite knowledgeable, and I like this quote best regarding tinnitus treatment:

"There are always options available.  If someone tells you there is nothing that can be done, you have to walk out the door."

Get the Popcorn

Below is a slide show that I've used when speaking to local civic groups. Though there are a lot of blanks without my narration, it might prove useful to you, nevertheless.

Relation Found Between SIDS and Hearing Acuity

It is estimated that for every 1,000 infants in the world, one dies as a result of Sudden Infant Death Syndrome (SIDS), making it is the leading cause of death among infants.

Up until now, warning signs as to which children are at greater risk for SIDS have been few and far between.  But researchers at Seattle's Children's Hospital may have discovered a screening for SIDS, and best of all, it is a test that is already in place in most of the fifty United States -- newborn hearing screenings.

From the press release:

One of the greatest medical mysteries of our time has taken a leap forward in medical understanding with new study results announced by Dr. Daniel D. Rubens of Children’s Hospital and Regional Medical Center in Seattle. Rubens’ study published in July, 2007 in Early Human Development found all babies in a Rhode Island study group who died of Sudden Infant Death Syndrome (SIDS) universally shared the same distinctive difference in their newborn hearing test results for the right inner ear, when compared to infants who did not have SIDS. This is the first time doctors might be able to identify newborns at risk for SIDS by a simple, affordable and routine hearing test administered shortly after birth. In the study, medical records and hearing tests of 31 babies who died from SIDS in Rhode Island were examined and compared to healthy babies. Rhode Island has a particularly robust database of newborn hearing test data.

The next step in research is to find out exactly why there is a link (the study's authors suggest that sensory cells in the inner ear also serve to measure carbon dioxide levels in the body, besides their role in hearing), which will hopefully lead to even better understanding and greater prevention of SIDS.

Amusing Anecdote

This past weekend, I was playing in a small golf tournament and one of my playing partners hit his ball and in mid-air, he began giving it instructions.  If you play golf, you'll know the type of thing I mean... "Carry, carry!" and "Come left! Come left!"

Once his ball had come to rest the equivalent of two football fields away from where we were standing, he bemused to the third member of our group, "The balls never listen, do they?"  In response, the third player pointed at me and said, "Don't tell me about it, he's the ear doc!"

It occurred to me, as odd as it sounds, there's probably a greater demand for improving the listening skills of golf balls than people!

Improved Performance Leads to Increased Acceptance of Amplification

In recent weeks, the advertising campaigns of a leading hearing aid manufacturer have received a significant amount of attention, both positive and negative (examples: 1, 2, 3).

While discussing the merits of the campaigns -- you can decide for yourself if they will be effective or not -- Phonak CEO Valentin Chapero tells Business Week, "It's very difficult when you are making a product that actually nobody wants."

It's true, there is very little demand for hearing aids, despite the fact that over 30 million Americans have some form of hearing loss.  But, there is reason to think that is going to change, and it has nothing whatsoever to do with a schnazzy ad campaign or catchy slogan.  It has everything to do with improved performance.  Several times a day, patients tell me that they are pleasantly surprised to find they have none of the complaints about hearing aids that their parents, aunts and uncles had about amplification.

The fact of the matter is, for decades hearing aids were incapable of processing sound in the manner that most patients with hearing loss need it to be processed.  They did not treat loudness growth differently across pitch ranges, something that is absolutely necessary for improved clarity along with loudness comfort.  It wasn't until the arrival of multi-channel devices in the early 1990's that this was possible, and it is only in the last five to seven years that the industry has gotten pretty good at designing devices that do it quite well (for more, read here).  It wasn't for lack of trying however, for many years we did not fully understand the nature of the ear and cochlear hearing loss and even if we did, the technology did not exist to engineer the devices anyway.

As time goes by and the success stories with hearing aids that people tell over a card game begin to finally outnumber the negative experiences recounted over the years at those same card games and family gatherings, gradually, people will become much more accepting of amplification.

Think about it this way.  If the automobile industry had failed, despite their best efforts, to improve upon the first "horseless carriages" and they remained unreliable and uncomfortable, would there be more cars in Los Angeles today than people (there really are, look it up)?  No.  Cars would have remained a product with a small niche until significant and worthwhile developments actually came about.  History tells us that when technology actually catches up with the needs of consumers, it is almost always a success.

As a matter of fact, the quality of today's hearing aids has audiologists and researchers thinking less about audibility at the ear-level and more about processing in the brain.

Useful Communication Tips

Over the past few weeks, we've spent a considerable amount of time and energy discussing advancements in technology to help those with hearing loss.  However, there are some very "low-tech" tricks for better hearing that have been applicable since humans first started to vocalize to each other about what might be outside the cave.

• If you are speaking to someone with hearing loss, make sure that you have their attention first.  When someone has hearing loss, comprehending the spoken word is a matter of filling in the blanks, and so if they are focused on you, there is a better chance they will understand you.

• Get face to face.  Patients are always flabbergasted when I tell them they read lips, but the truth is, we learn to do it at a very young age, right when we begin to learn language.  Again, comprehending speech when you have a hearing loss is a matter of filling in the blanks, and having some visual cues (a "b" looks much different on the lips than a "t") to go along with the sounds that are getting through goes a long way to better comprehension.

• Rephrase something if it just isn't getting through.  Different sounds of speech have different pitches and if someone with hearing loss just can't catch what's being said no matter how many times or how loudly it's repeated, it is likely that a particular sound or two is just inaudible.  The solution is to rephrase the statement or question, which will in turn use slightly different pitches.

• Reduce the amount of background noise.  People with hearing loss have a difficulty time sorting out what they want to hear from what they would prefer to tune out.  By reducing the amount of background noise, there will be greater separation between the competing sounds that the desired signal.  For instance, if someone has normal hearing, they can correctly comprehend speech at a rate of 50% if the competing noise and the speaker are at the same level of intensity.  On the other hand, for someone with sensorineural hearing loss -- the most common type -- to perceive what the speaker is saying, the speaker must be at least 10 decibels louder than the competing noise.

• Speak slower.  Someone with hearing loss has to do twice the work to understand what is being said as someone with normal hearing.  Rapid speech makes it difficult for the person to keep up and fill in the blanks (think of Lucy and Ethel at the chocolate factory).  Slower speech, on the other hand, is easier for a person to decipher.
  

All of the above, when you think about it, are nothing more than common sense and are actually good advice for anyone, whether there is a hearing loss present or not.  Patients who use these tips in conjunction with hearing aids seen even greater improvement in their ability to communicate.

Open-Ear Devices Offer Great Improvement

Every once in a while, an area that had been experiencing small incremental improvements suddenly enters an era that represents a much larger advancement.  In the area of hearing aids and amplification, the recent introduction of "open-ear" devices has significantly changed the way audiologists and patients think of improving communication.

Open-ear hearing aids rest behind a patient's ear and a thin tube, almost like fishing-line, comes down the front of the pinna and curves into the ear canal [see graphic].  This configuration provides several advantages over more traditional in-the-ear or canal-style hearing aids:

• Sound-quality: Since the ear is not occluded by a hearing aid, there is no insertion loss (the additional hearing loss created when an object, such as a hearing aid, is inserted into the ear) to overcome.  Therefore, a patient's own voice will sound more natural to them and other sounds in their environment will not sound as amplified or unnatural.

• Comfort:  Because very little of the device is actually making contact with a user's ear canal, the device feels much more comfortable.  As a matter of fact, most patient's report that they forget the hearing aids are even there.

• Reliability: All of the electronic components reside in the casing behind the ear.  This makes the device much less susceptable to the hazards of the human ear canal.  Traditional hearing aids all too often break down due to cerumen and debris damage or moisture collection.  But if all of the electronics are behind the ear, all of these issues become nearly irrelavent.  Moisture is still somewhat of a concern, but not nearly to the degree that it is with traditional devices.  Anecdotally, I can report that in our offices, we rarely repair open-ear devices.

Just a few years ago, 80% of the hearing aids dispensed in the United States were hearing aids that fit entirely in the ear with only 20% of the devices dispensed fitting behind the ear.  Today, the ratio is now approximately 50/50, and that change is due to the emergence of open-ear devices.

While open-ear devices are not appropriate for everyone with hearing loss (severe losses are out of the fitting range), they are clearly one of the best options for many patients, particularly when combined with modern digital processing.  Consult your audiologist to find out if open-ear devices are right for you.

Gadgets Inspired by the Inner Ear

One of the reasons audiology is an interesting profession is, well, frankly, we get to play with gadgets.  Be it a digital hearing aid, sound-level meters, or a piece of diagnostic equipment, audiologists have their fair share of toys.

If you find medical gadgets and technological advancements interesting, then a website I would highly recommend is Medgadget.  Hearing science is often featured on the site -- in recent weeks there have been entries on a "do-it-yourself" video-otoscope, an at-home kit to screen your child for an ear infection, a vibratory fire-alarm clock for the hearing-impaired, and a hypothesis by scientists that nerves do not actually use electrical charges to transmit signals, but actually use sound to transmit signals.

An entry on Medgadget about two weeks ago featured a device for alerting drowsy drivers to wake up.  What's interesting about the device is how it illustrates how engineers often are inspired by the inner workings of the human body.  In this case, the user wears a device on his/her ear that makes a loud beeping sound if the user's head tilts forward just ten degrees.

Clearly, this device was inspired by the inner ear and the vestibular system.  The inner ear is filled with fluid and when the head is tilted, the fluid in the inner ear moves in response to gravity, which in turn stimulates sensory cells in the vestibular portion of the inner ear.  These cells in turn send signals to the brainstem and brain that the head is moving in space.

What will they think of next...

Promising News in the Prevention of Noise-Induced Hearing Loss

The best way to prevent noise-induced hearing loss is simple: avoid excessive noise [I'm looking at you, iPod User].

Unfortunately for some, that isn't possible.  Certain occupations require people to be in noise to do their jobs -- soldiers, construction workers, pilots, etc. -- and while the use of hearing protection does a good job, it isn't perfect, nor is it always possible to use it 100% of the time.

In a press release, researchers at the Washington University in St. Louis announced they may have found a pharmacological form of protection:

Research at Washington University School of Medicine in St. Louis suggests a medicinal form of hearing protection may someday be a possibility. A group headed by Jianxin Bao, Ph.D., research associate professor of otolaryngology and head of the Central Institute for the Deaf's Presbycusis and Aging Laboratory, has found that two anti-epileptic drugs can prevent permanent hearing loss to a significant degree in mice exposed to loud noises.

As with any study, there are details to be considered.  Firstly, the medication reduced the hearing loss by 5 decibels, however, the mice still exhibited hearing loss.  Make no mistake, 5 dB is significant, but it's not as if the drugs will give you ears of steel.  Secondly, the proper dosages and side effects must be determined for humans.

Very promising for sure, but still several years away from being available for the general public.

The methodolgy and results of the study will be published in Hearing Research.