Print

Types of Hearing Loss

Close your eyes and concentrate. As you listen, you may notice a wide variety of activities around you. The sound of a lawnmower. A car passing by on the street. Or the rhythmic sound of your own breathing. What you are experiencing are the vibrations of sound that surround us.

Normally, the human ear is remarkably sensitive to a wide range   of acoustical activity, which is processed by the ear, our nervous system and brain into what we perceive as sound.

There can be many reasons why our ability to hear sounds diminishes. The ear is a delicate instrument. It may break down, or simply wear out.   The ear is composed of 3 parts: the outer, the middle, and inner ear. The outer ear consists of the pinna and the ear canal. From the pinna, sound enters the ear canal, which helps protect the ear drum and increases the loudness of certain pitches that are important for understanding speech.

Separating the outer ear from the middle ear is the eardrum, and connecting the eardrum to the inner ear are the ossicles: 3 tiny bones best known as the hammer, the anvil and the stirrup. The ossicles serve to pass the vibrations from the eardrum to the footplate of the stirrup at the cochlea, or snail, and at the same time amplifying and intensifying the movement. The middle ear also has a connection to the nose and throat via the Eustachian tube.

When sound cannot be transmitted normally through the ear canal and/or middle ear to the cochlea, it is referred to as a conductive hearing loss. Wax build-up and perforated eardrums are 2 typical causes of conductive hearing losses. Another may be damaged or defective oscicles.

As sound vibrations are transmitted to the cochlea in the inner ear, they set tiny hair cells in motion. These hair cells transform the vibrations into nerve impulses, which are picked up by the acoustic nerve and sent to the brain.

The inner ear is very fragile, so many things can go wrong. Exposure to loud sounds can damage the hair cells, so sound can't be converted into nerve impulses and transmitted to the brain. Disease, viruses, and infections can also injure the inner ear. So can aging. Hair cells may deteriorate as may nerve pathways, preventing the signal from the ear from reaching the brain. These types of problems are referred to as sensorineural hearing losses.

Sensorineural hearing losses affect our sensitivity to sounds, as well as our ability to discriminate between sounds. For example, individual words may seem unintelligible during conversation.

Hearing losses that are caused by both conductive and senso-rineural impairments are termed mixed or combined losses.

No matter what the nature of your hearing loss, a hearing care professional can conduct a painless investigation which takes less than an hour to perform, to evaluate your hearing loss and recommend the best treatment.