The ear is made up of three parts: the outer, middle, and inner ear. All three parts of the ear are important for detecting sound by working together to move sound from the outer part through the middle and into the inner part of the ear. Ears also help to maintain balance.
The outer ear includes:
- auricle (cartilage covered by skin placed on opposite sides of the head)
- auditory canal (also called the ear canal)
- eardrum outer layer (also called the tympanic membrane)
The outer part of the ear collects sound. Sound travels through the auricle and the auditory canal, a short tube that ends at the eardrum.
The middle ear includes:
- cavity (also called the tympanic cavity)
- ossicles (3 tiny bones – malleus – incus – stapes)
- malleus (or hammer) – long handle attached to the eardrum
- incus (or anvil) – the bridge bone between the malleus and the stapes
- stapes (or stirrup) – the footplate; the smallest bone in the body
- eustachian tube
Sound entering the outer ear travels through the middle ear and causes the eardrum and ossicles in the middle ear to vibrate; conducting sound from the outer to the inner ear.
The inner ear includes:
- oval window – connects the middle ear with the inner ear
- semicircular ducts – filled with fluid; attached to cochlea and nerves; sends information on balance and head position to the brain
- cochlea – spiral-shaped organ of hearing; transforms sound into signals that get sent to the brain – damage within the cochlea represents the majority of hearing loss that we see – when the cochlea is damaged, the signal sent to the brain is reduced or limited
When the stapes moves, it pushes the oval window, which then moves the cochlea. The cochlea takes the fluid vibration of sounds from the surrounding semicircular ducts and translates them into signals that are sent to the brain by nerves like the vestibular nerve and cochlear nerve.
Millions of people suffer from hearing loss. In fact, the latest available statistics show that over 10% of the U.S. population reports difficulty hearing. That’s more than 31 million people! And as the Baby Boomer generation continues to age, that number promises to increase dramatically.
Are you one of those millions of people who does not hear as well as they once did? If so, you are certainly not alone. Consider these statistics reported by Sergei Kochkin, Ph.D., Executive Director of the Better Hearing Institute:
- 3 in 10 people (30%) over the age of 60 have hearing loss
- 1 in 6 Baby Boomers (ages 41-59), or 14.6%, have a hearing problem
- 1 in 14 (7.4%) of the Generation X population (ages 29-40) already have hearing loss
Causes of Hearing Loss
There are several causes of hearing loss with “exposure to noise” ranking high among the reasons. The primary causes of hearing loss are:
- Exposure to noise
- Family history of hearing loss
- Aging process
- Various diseases
- Head trauma
- Ear infections
- High fevers
Various types of hearing loss
|Conductive||This could be caused by something as simple as earwax buildup or a possible issue with the eardrum and/or the tiny bones in the middle ear.|
|Sensorineural||This is caused when tiny hairs in the cochlea are missing or damaged.|
|Mixed||This is a combination of conductive and sensorineural hearing loss.|
|Central||Strokes and central nerve diseases are often the cause of this type of hearing loss.|
Do you hear a ringing, roaring, clicking, or hissing sound in your ears? Do you hear this sound often or all the time? Does the sound bother you a lot? If you answer yes to these questions, you may have tinnitus.
Tinnitus is a symptom associated with many forms of hearing loss. It can also be a symptom of other health problems. Approximately 25 million Americans have experienced tinnitus. Some cases are so severe that it interferes with their daily activities. People with severe cases of tinnitus may find it difficult to hear, work, or even sleep.
While there is no “cure” for Tinnitus, we do offer hearing instruments that can help mask over it.
Hearing Loss and Dementia
Johns Hopkins Medicine has reported that people with mild, moderate and severe hearing loss are 2, 3 and 5x more likely to develop dementia than those people with normal hearing. Even after researchers took into account other factors that are associated with dementia, including diabetes, high blood pressure, age, sex and race, hearing loss and dementia are still strongly connected.
Charlie Rose Brain Series 2, Episode 15
Click on the button below to view a Charlie Rose episode regarding hearing loss with Eric Kandel of Columbia University, David Corey of Harvard University, Frank Lin of Johns Hopkins University, Ruth Bentler of the University of Iowa and Dr. Ingeborg Hochmair.