Understanding the Ear

The ear is comprised of three parts: the outer ear, the middle ear, and the inner ear. Each of these parts has their own function in the hearing process.

The Outer Ear

The Middle Ear

The Inner Ear



The Outer Ear

THE OUTER EAR includes the pinna and ear canal. The outer ear funnels sound to the eardrum and deeper structures in the ear. The shape of the outer ear also amplifies the softer high-frequency sounds of speech.

The eardrum separates the outer ear from the middle ear. After sound has been funneled through the ear canal, the force of that sound causes the eardrum to vibrate.


The Middle Ear

THE MIDDLE EAR contains a chain of three very small bones that are attached to the eardrum. These bones, called the malleus, incus, and stapes, pick up the tiny vibrations of the eardrum. These three bones act like a series of levers to make the vibrations of the eardrum more intense.


The Inner Ear

THE INNER EAR includes the organs of hearing and balance. The part of the inner ear devoted to the hearing process is the cochlea (pronounced COKE-lee-uh). When sound vibrations reach the cochlea, microscopic fibrous cells called hair cells change sound from one form of energy to another. Hair cells in the cochlea change sound from a vibratory movement into electrical signals that are then sent up to the brain. After the cochlea has converted sound into an electrical signal, that signal is sent up the auditory nerve to the brain where all understanding of speech occurs. Most patients with sensorineural hearing loss have damage to these hair cells, meaning that soft sounds never get efficiently converted to a form of energy that the brain can understand.


HEARING LOSS can occur when there’s a problem with any part of this process. Your audiologist will use very specific diagnostic tests to locate the origin of the hearing loss. Hearing loss may be temporary or permanent, depending on which part of the process is impaired. If your test results indicate a problem that is likely to be medically treatable, you will be referred to a physician for further consultation. If your tests indicate a permanent hearing loss, your audiologist will recommend the best course of treatment and education to improve your communication skills.


1)   CONDUCTIVE HEARING LOSS occurs when sound vibrations don’t have a clear the path through the ear canal or aren’t getting efficiently passed through the bones of the middle ear. Most conductive problems can be treated with medication or surgery. The most common causes of conductive hearing loss include:

  • Ear canal blockage. Earwax normally migrates out of the ear on its own, but if it builds up, the earwax can become an earplug, causing a correctable hearing loss.
  • Otitis media (an ear infection) can cause fluid to build up around the eardrum and middle ear bones. This causes mechanical problems that block the normal function of these structures.

2)   SENSORINEURAL HEARING LOSS results from a problem with the cochlea or auditory nerve. This type of hearing loss can range from a very mild problem to a loss of hearing depending on the extent of the damage.

Exposure to loud noises can cause damage to the hair cells in the inner ear. If the force of the sound is very intense, such as an explosion, the damage may occur instantly. If the noise exposure is more moderate, such as small firearms, factory machinery, or kindergarten classrooms, it may take years or decades for the damage to build up.

Aging is associated with hearing loss. We actually start damaging our ears in childhood, and we continue to lose tiny bits of hearing function every year. By the age of 50, about 25% of us will have significant hearing loss due to age-related degeneration of the inner ear.

Genetics can also play a role in hearing loss. Genetically-inherited factors can cause a hearing loss from birth or can predispose you to hearing loss later in life.

3)   MIXED HEARING LOSS is simply a combination of conductive and sensorineural hearing losses. Patients with mixed hearing loss will typically have the conductive portion of their hearing loss treated by a medical doctor. The sensorineural portion of this hearing loss will be treated by an audiologist.

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Understanding Your Audiogram

The graph below is called an audiogram. During your evaluation, you listened to tones ranging from deep bass to shrill treble pitches. The softest level of sound that allows you to just barely detect each tone is called your threshold. Your threshold for each pitch is plotted on the audiogram. The O symbols represent thresholds for your right ear, and the X symbols represent thresholds for your left ear. If you were able to hear very soft sounds, your thresholds will be located at the top of the graph. The lower the marks fall on the graph, the louder the sounds had to be for you to hear them. You’re able to hear only part of the most important speech area that falls below your thresholds on the audiogram.

Mild hearing loss causes problems understanding speech when the listening environment is not perfect. People with mild hearing loss can usually understand conversation in a quiet room if they are facing the talker. Many people with ild hearing loss find that hearing aids give them the little bit of added help they need to communicate effectively.

Moderate hearing loss causes difficulty understanding speech in many situations. People with moderate hearing loss may always hear that people are talking, but will have frequent difficulty understanding speech without hearing aids.

Severe and profound hearing losses are devastating to speech understanding if not treated with hearing aids. People with this level of hearing loss frequently do well with hearing aids. If the damage to the ears is so profound that amplification is not enough to allow speech understanding, surgically implanted devices may be discussed as an option.

Audiogram Example


Tinnitus is any noise you can hear, but it doesn’t come from a source in the outside world. As a person with constant tinnitus myself, I know this can be very disturbing at times. In some people, it can cause depression, anxiety, fatigue, and anger. There are a number of approaches we can take to help you learn to live with tinnitus if you can come to Audiology Center Northwest’s Portland Oregon Clinic. We are finding that in about half the cases, hearing aids are a great help at relieving tinnitus. In the other half of cases, another type of listening therapy may be more effective at providing some relief.

Call us at 503 232-1845 to see how we can help you with your tinnitus.

Contact us today for a hearing consultation.

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Suite 170N
Portland, OR 97232

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