Hearing and Healthcare
How your ear works:
The Outer Ear
The two features of the outer ear include the pinna and the ear canal. They act together to funnel sound into the ear to the ear drum. The shape and size of the outer ear and especially the ear canal help to improve the ability to hear certain sounds. Inside the ear canal are hair follicles and ear wax.
The Middle Ear
The middle ear begins on the inside of the ear drum. As sounds hit the ear drum it begins to vibrate. These vibrations move the bones on the inside of the ear drum in a back and forth motion. These are the three smallest bones in the body. Together they are called the ossicular chain, or the ossicles. The malleus is attached to the ear drum. The next bone is the incus followed by the stapes which is also attached to the oval window of the cochlea.
The Inner Ear
The inner ear begins at the cochlea. The cochlea is snail shaped and housed in the bones of the skull. When the stapes moves the oval window back and forth, the fluid within the cochlea begins to move in a wave-like pattern. These waves make tiny hairs rub against other structures in the cochlea creating chemical reactions. Different sounds create different waves; the variety of waves create multiple chemical reactions. These reactions are sent along the nervous system to be interpreted by the brain as sounds.
Types of hearing loss:
Conductive, Sensorineural, Mixed and Central are the main types of hearing loss.
Conductive Hearing Loss:
This type of loss occurs when sound is blocked from passing through the outer or middle ear. Some causes may be ear infections, problems with the ear drum, too much wax in the ear, or problems with the bones in the middle ear. Many times conductive hearing losses are temporary. Some may be surgically corrected. In rare cases a correction is not possible or needs to be delayed.
Sensorineural Hearing Loss:
This type of loss that occurs when sound passes through the outer and middle ear, but cannot successful move through the inner ear. Some causes may be illness, taking certain medications, the aging process, or noise exposure. These losses typically cannot be corrected. This hearing loss may be further dissected into a sensory loss or a neural loss. A sensory loss occurs when the loss is known to result from a problem with the cochlea. A neural loss results when the loss is known to occur with the nerve that sends information to the brain.
Mixed Hearing Loss
This is a loss that occurs when both conductive and sensorineural hearing losses are present at the same time.
Central Hearing Loss
This type of hearing loss occurs when the signal makes its way through the outer, middle and outer ear systems successfully, but the brain is unable to process the information.