Understanding Hearing Disorders: Types, Causes, and Impact
Hearing loss is a common condition that affects people of all ages. It knows no age limits. When you break it down, about 15 percent of adults in the United States (18 and older) report some trouble hearing-roughly 37.5 million people. Among younger Americans, roughly 15 percent of teens-12-to-19 year old’s-have some degree of hearing loss. Hearing problems don’t discriminate and can affect people at any stage of life.
Hearing loss can come on gradually or suddenly. And the underlying causes range from genetics, to infections, to the side-effects of certain medicines, to aging.
Hearing is an important part of your everyday life. Hearing loss can impact your life in so many ways. As America ages and we’re bombarded by the noise of modern-day living, hearing loss has become a growing public health concern. Today, it’s the third most common chronic health condition in the United States.
Left unaddressed, hearing loss can have a profound effect on people’s lives-from interpersonal communication, to health and quality of life. In recent years, researchers have gained a greater understanding of the connection between hearing loss and other health concerns. In fact, studies show a link between hearing loss and cognitive function and dementia, depression, diabetes, cardiovascular disease, moderate chronic kidney disease, rheumatoid arthritis, obesity, sleep apnea, and an increased risk of falls.
If you think you have hearing loss, talk to a healthcare provider or audiologist. They’ll determine the best way to improve your hearing.
The Hearing Process
Our ability to hear is a fascinating phenomenon. In simple terms, we hear when a series of sound waves, or vibrations, pass through our outer, middle and inner ear and reach our brain for interpretation.
More specifically, the hearing process starts with sound waves collecting in the outer ear, passing through the ear canal, and causing the eardrum to vibrate. When the vibrations reach the cochlea (pronounced coke-lee-a) in the inner ear, via movement of the bones in the middle ear, the fluid within the cochlea begins to move. This sets off back and forth motion of tiny hair cells (nerve endings or sensory receptors) lining the cochlea. This motion, in turn, results in the hair cells sending a signal along the auditory nerve to the brain.
Along the brainstem these nerve signals from the two ears are mixed and compared at several stages. These processes help with everyday functions such as our ability to locate a sound in space.
Figure 1. The anatomy of the human ear.
The outer ear consists of the part of the ear you can see, in addition to the narrow, tube-like opening called the ear canal. The inner ear is made up of two components: one involved with hearing, the cochlea, and the other with balance, the vestibular system. The cochlea is a snail-shaped chamber filled with fluid and lined with sensory receptors in the form of tiny hair cells. It’s attached to the auditory, or hearing, nerve that leads to the brain.
Types of Hearing Loss
Hearing loss affects people of all ages and can be caused by many different factors. The three basic categories of hearing loss are sensorineural hearing loss, conductive hearing loss and mixed hearing loss.
Sensorineural Hearing Loss
This type of hearing loss occurs when the inner ear or the actual hearing nerve itself becomes damaged. Sensorineural loss is the most common type of hearing loss. It can be a result of aging, exposure to loud noise, injury, disease, certain drugs or an inherited condition. Sudden sensorineural hearing loss may occur very suddenly or over the course of a few days. It is imperative to see an otologist (a doctor specializing in diseases of the ear) immediately.
Most hearing loss is sensorineural hearing loss and involves either the loss of inner ear hair cells or fibers of the auditory nerve. Without these hair cells-which vibrate in response to sound waves, sending signals along the auditory nerve to the brain-we cannot hear. Once destroyed, the body doesn’t replace either the hair cells or the nerve fibers.
Conductive Hearing Loss
This type of hearing loss occurs in the outer or middle ear where sound waves are not able to carry all the way through to the inner ear. In some people, conductive hearing loss may be reversed through medical or surgical intervention.
Conductive hearing loss involves a physical problem with the functioning mechanics of the outer or middle ear. Basically, something is impeding sound from moving from the outer to middle or inner ear. This can be as simple as a build-up of ear wax. Or it can be a physical object-such as a tiny bead or pieces of cotton swabs-stuck in the ear canal. It also can result from fluid in the middle ear, a hole in the eardrum, birth defects, a condition known as otosclerosis, or a cholesteatoma-a noncancerous skin growth behind the eardrum-among other things.
Mixed Hearing Loss
Sometimes people can have a combination of both sensorineural and conductive hearing loss.
Degrees of Hearing Loss
When someone is diagnosed with hearing loss, it can mean many things.
- Mild Hearing Loss: Typically, people with mild hearing loss only notice difficulty hearing in specific circumstances-like following conversation in a noisy environment.
- Moderate Hearing Loss: People with moderate hearing loss have a more difficult time and may find themselves asking people to repeat themselves, especially when on the phone. Following group conversations may be difficult, as well.
- Severe Hearing Loss: People with severe hearing loss usually need to rely on lipreading or the use of a hearing aid or other assistive listening device to follow the conversation.
- Profound Hearing Loss: Profound hearing loss means that someone can’t hear what another person is saying unless it’s extremely loud. Understanding the conversation usually requires a hearing aid or cochlear implant. Some people with profound hearing loss prefer to use sign language to communicate.
Hearing Loss and its Impact
Hearing loss can be temporary, but many people have hearing loss that doesn’t go away. Hearing loss may make you feel as if you’re missing out on life. You may feel uncomfortable trying to carry on telephone conversations or frustrated because you can’t enjoy your favorite movies or shows. You may feel isolated or depressed.
When people experience hearing loss, it can significantly affect many dimensions of their lives-from personal relationships, to their work life, to their level of engagement in social situations.
Hearing Tests and Solutions
Hearing testing is critical for discovering exactly what type of hearing loss you have, and will help determine the hearing care solution that is right for you. Most adults received their last hearing test when they were in grade school. It is a good idea to have your hearing checked when you are an adult at least once during your annual physical.
If you are considering a hearing aid, you are bound to have questions. There are many kinds of over-the-counter hearing aids on the market, ranging from inexpensive hand-held amplifiers to self-fit devices that can be calibrated to your amplification needs with a smartphone app.
People over age 50 may experience gradual hearing loss over the years due to age-related changes in the ear or auditory nerve. The medical term for age-related hearing loss is presbycusis.
Our center’s physicians are among the finest and most highly skilled otologists and neurotologists (ear, nose and throat doctors) in the world.
| Type of Hearing Loss | Location of Issue | Potential Causes | Possible Solutions |
|---|---|---|---|
| Sensorineural | Inner ear or auditory nerve | Aging, noise exposure, injury, disease, genetics | Hearing aids, cochlear implants |
| Conductive | Outer or middle ear | Earwax buildup, foreign objects, fluid, eardrum damage | Medical intervention, surgery |
| Mixed | Combination of inner/outer or middle ear | Combination of causes from both types | Combination of treatments |