Hearing – Eyesight’s Backup
Keeping in Touch with What is Around You
While eyesight is the most important sense a person has for collecting critical information for driving, it can collect only what is in front of it and to limited extent, what is on the periphery. How does a driver know when to turn and face another direction from which vital cues can be gathered. Hearing, serves as the next most commonly used sensory mechanism to supplement our eyesight.
While the eyes are focused on what is ahead:
- the distant sounds of a siren can alert you to an approaching ambulance, police car or fire truck, from any given direction
- a whistle can warn you of a policeman’s directions as he manages the stop and go of traffic at an intersection
- the sound of tires screeching and cars careening around a corner tell you that some someone nearby is going at high speeds and is losing control
- the horrific crunch of metal behind you tells that at least two cars have collided
- the sickening splat resulting from the impact of a car against human body or by a pedestrian’s contact with the pavement announce bespeaks heartbreak
Hearing helps keep you in touch with what happens around you, especially while your eyesight is occupied.
Typical Auditory Cues Comprising an Auditory Survey
The auditory survey is essentially a passive activity, but the information gathered can often be as critical as an active visual survey. The many auditory cues that a person surveys while driving, include mainly those sounds emanating from within the car and those from without.
From your car, sounds you might hear include:
- Metallic screeching or scraping
- Clunking or thumping
- Heavy knocking/ pounding from the engine/drive train
- Pinking or Pinging of engine
- Low pitched rumble
- Ticking increasing in speed while revving
From beyond your car, sounds you might hear include:
- Sirens-Ambulances, police cars, tire trucks, emergency vehicles
- Tires screeching while breaking
- Sounds of impact: collisions
- Sounds of impact: pedestrians
All of these sounds are common and frequent during the operation of a car. Anyone of them, especially those sounds originating from outside, can be critical to accurately surveying the driving environment you face
Hearing loss can make it difficult for you to hear high-pitched sounds such as sirens and instrument panel warning signals. You may also find it hard to hear certain sounds when there is background noise, such as passengers speaking, radio blaring or outside traffic noise is present.
To make matters worse, hearing loss is also part of getting older. One-third of Americans between 65-75 and one-half of Americans over 75 have a hearing loss. We begin to lose auditory sensory cells already in the late teens. Gradual loss, presbycusis, a change in the inner ear, is the most common form of hearing loss. Often the changes are unnoticeable, at first.
Types of Hearing Deterioration Affecting Our Driving
There are two general categories of hearing loss.
- Sensorineural hearing loss occurs when there is damage to the inner ear or the auditory nerve. This type of hearing loss is usually permanent.
- Conductive hearing loss occurs when sound waves cannot reach the inner ear. The cause may be earwax build-up, fluid, or a punctured eardrum. Medical treatment or surgery can usually restore conductive hearing loss.
What is Presbycusis?
One form of hearing loss, presbycusis, comes on gradually as a person ages. Presbycusis can occur because of changes in the inner ear, auditory nerve, middle ear, or outer ear. Some of its causes are aging, loud noise, heredity, head injury, infection, illness, certain prescription drugs, and circulation problems such as high blood pressure.
Presbycusis commonly affects people over 50, many of whom are likely to lose some hearing each year. Having presbycusis may make it hard for a person to tolerate loud sounds or to hear what others are saying.
Tinnitus: A Common Symptom
Tinnitus, also common in older people, is a ringing, roaring, clicking, hissing, or buzzing sound. It can come and go. It might be heard in one or both ears and be loud or soft.
Tinnitus is a symptom, not a disease. It can accompany any type of hearing loss. It can be a side effect of medications. Something as simple as a piece of earwax blocking the ear canal can cause tinnitus, but it can also be the result of a number of health conditions.
If you think you have tinnitus, see your primary care doctor. You may be referred to an otolaryngologist — a surgeon who specializes in ear, nose, and throat diseases — (commonly called an ear, nose, and throat doctor, or an ENT). The ENT will physically examine your head, neck, and ears and test your hearing to determine the appropriate treatment.
Hearing Loss Can Lead to Other Problems
Depression or Withdrawal
Some people may not want to admit they have trouble hearing. Older people who can’t hear well may become depressed or may withdraw from others to avoid feeling frustrated or embarrassed about not understanding what is being said. Sometimes older people are mistakenly thought to be confused, unresponsive, or uncooperative just because they don’t hear well.
Hearing problems that are ignored or untreated can get worse. If you have a hearing problem, you can get help. See your doctor. Hearing aids, special training, certain medicines, and surgery are some of the choices that can help people with hearing problems.
Just last year, the New York Times published an article concerning hearing loss and dementia and said the following:
Hearing and the Brain
“Although hearing impairment was first linked in major medical journals to dementia and cognitive dysfunction more than two decades ago, not until last year did researchers demonstrate an independent association with dementia over time. By following 639 people ages 36 to 90 for nearly 12 years, Dr. Frank R. Lin, an otolaryngologist at Johns Hopkins Medicine, and his colleagues there and at the National Institute on Aging showed a direct relationship between the participants’ degree of hearing loss and their risk of later developing dementia or Alzheimer’s disease.”
The article continued with the following conclusions,
” How, then, might this lead to cognitive deficits?
“The brain dedicates a lot of resources to hearing,” Dr. Lin said. “When the clarity of words is garbled, the brain gets a garbled message. It has to reallocate resources to hear at the expense of other brain functions.”
Thus, the overworked brain may lose “cognitive reserve,” the ability of healthy parts of the brain to take over functions lost by other parts.
Another mechanism may be the effects of social isolation. “A decline in social engagement and resulting loneliness is one of the most important determinants of health outcomes in older adults,” Dr. Lin said. “Isolation has been linked to an increase in inflammation throughout the body, which in turn can result in age-related disorders like heart disease and dementia”, Dr. Lin said.
Conditions That May Lead to At-Risk Driving
Many hearing conditions can limit effective and safe driving. Holly St. Lifer, in the April/May 2013 edition of the AARP The Magazine, spells out common hearing problems that may lead to curtailment of driving.
1. You have trouble hearing people in a noisy restaurant
As you age — especially if you’ve been exposed to frequent loud noises — you might have presbycusis, a type of gradual hearing loss caused by the death of hair cells in the cochlea, in your inner ear. Those are the cells that translate sound vibrations into brain signals.
“The cochlea contains only 15,000 of these hair cells, and they don’t regenerate,” says Andrea Boidman, executive director of the Hearing Health Foundation, a research organization in New York. “When they die, it becomes difficult for people to recognize certain sounds or to hear speech clearly.” Difficulty hearing in noisy places is often one of the first noticeable signs of hearing loss. That’s because filtering out background noise is a fairly complex process that requires precise auditory input from both ears. Quiet conversations aren’t quite so taxing
People with kidney or heart disease have a higher than average risk of developing presbycusis. Researchers think that may be because poor kidney function leads to the accumulation of toxins that can damage nerves in the inner ear. And cardiovascular disease can decrease blood flow to the inner ear. “Improving kidney or cardiac function won’t reverse hearing loss, but it can prevent it from worsening,” says Okun. “I recommend getting a formal hearing test if you have either condition.” The reverse may be true as well; if you have hearing loss, check your kidney and cardiovascular health.
Although you can’t repair damaged cells, you can prevent further loss by limiting your exposure to loud noises. Most conversations occur between 40 and 60 decibels; any sound higher than 85 decibels puts you at risk. Common culprits include electronic devices like iPods, music players and sound speakers that can blast out as many as 105 decibels.
“Listening to just one loud song can cause immediate damage to hair cells,” says Monica Okun, M.D., an ear, nose and throat specialist at Lenox Hill Hospital in New York. Her advice: If others can hear your iPod while you’re using earbuds, the music is too loud.
If your hearing loss is starting to affect your everyday activities, talk to your doctor about a hearing aid. And before you balk, consider this: The newest models are so sleek that they’re practically invisible.
“The latest technology effectively reduces background noise while simultaneously enhancing the ability to hear speech more clearly,” says Ellen Finkelstein, chief audiologist at East Side Audiology in New York. “People can also hear voices that would be completely inaudible otherwise.” For severe hearing loss, you may want to consider cochlear implants. Whereas hearing aids amplify sounds so that damaged ears can detect them, cochlear implants bypass damaged parts and directly stimulate the auditory nerve.
2. You have a feeling of fullness in your ears
Excess mucus from an infection or allergy can block the eustachian tube, the small canal that connects the throat to the middle ear and regulates airflow, particularly when you swallow or yawn. Besides feeling fullness and muffled hearing, you might also experience popping, pain or tinnitus (ringing in the ears) or have difficulty maintaining balance. A buildup of earwax can cause that feeling of fullness, too. Hearing loss with fullness that’s accompanied by significant pain could be otitis externa, or swimmer’s ear, an infection of the ear canal that carries sound to the eardrums. The infection is typically caused by water in the ear, which breaks down the skin and provides a breeding ground for bacteria. Otitis externa is usually treated with ear drops that contain an antibiotic.
“Most eustachian tube dysfunctions improve when the infection goes away,” says David S. Haynes, M.D., Cochlear Implant Program director at Vanderbilt University Medical Center in Nashville. If not, a doctor can prescribe decongestants and antihistamines to help reduce inflammation. As for earwax, any health care provider can remove it with a suction device, irrigation tool or nasal spray, Haynes says. Don’t try to do it yourself, though, as you can easily damage your eardrum
3. Your hearing loss is sudden
Swelling or fluid buildup as a result of a virus or ear infection can affect hair cells and nerves, as can taking high doses of certain medications, including aspirin, IV antibiotics, chemotherapy drugs and diuretics. See your physician if you have sudden hearing loss. In rare circumstances, this could be the sign of a tumor pressing on the auditory nerve. Other uncommon causes include syphilis, Lyme disease, autoimmune disorders and thyroid disease. “If an audiogram shows nerve injury, hearing can be recovered if steroids are given within 72 hours of the onset of hearing loss,” says Okun. Steroids reduce inflammation and prevent swelling of the auditory nerve, which, if left untreated, can cause permanent hearing loss. Loss of hearing because of use of certain drugs — a condition called ototoxicity — requires an immediate change in your medication, if possible.
4. Hearing loss fluctuates and is accompanied by dizziness, nausea or trouble with balance
This hearing loss condition is known as Ménière’s disease, an uncommon disorder with no known cause, that alters the amount, flow and chemical composition of endolymph, the fluid in the inner ear. It is relatively uncommon but still affects one in 500 people in the United States. It is accompanied by dizziness with fluctuating hearing loss which can signal other medical conditions such as a change in blood pressure, cardiovascular problems, dehydration and anxiety. If you’re experiencing this type of hearing loss, consult your primary care physician or an ear, nose and throat specialist right away.
While Ménière’s can not be cured, it can be treated. Usually, a low-sodium diet and a prescribed diuretic can help reduce fluid in the inner ear. In rare cases, doctors may recommend injecting a steroid into the middle ear to reduce inflammation, or inserting a tube into the ear to drain excess fluid.
When Should You Be Concerned About Your Hearing
- Do I always ask someone to repeat things?
- Do I strain to hear?
- Do I favour one ear?
- Do I think that people always mumble?
- Do I hear ringing or buzzing in the ears (tinnitus)?
- Do I misunderstand conversations?
What to Do About these Signs
- Have regular hearing exams or speak to your health care provider.
- Wear your recommended hearing aid(s). Keep extra batteries on hand.
- Limit background noise while driving (e.g. radio, chatter, air conditioner).
- Watch for flashing lights of emergency vehicles. You may not hear the siren.
- Watch for the flashing lights and barriers at railway crossings
- Take preventive measures to keep your hearing healthy