Tuesday, January 27, 2009

A "bit" on hearing loss and such

I haven't made a post in quite awhile. My versatas are great...took me a bit to get used to wearing both hearing aids, but it hasn't been too bad. My voice sounded a bit weird tho..

Anyways I wanted to make a post about hearing loss and good bits of info so here it is:)

The anatomy of the hearing system can be divided into four components for our convenience in remembering the parts and associating these parts with their function. These divisions are the:
1. outer ear:The outer ear is made up of the pinna or auricle and the external auditory canal. The pinna collects and funnels sound down the ear canal. The ear canal is curved, “S” shaped, and about 1 inch long in adults. It has hairs and glands that produce wax called cerumen. Cerumen helps to lubricate the skin and keep it moist.

2. middle ear:The eardrum (tympanic membrane) is a membrane at the inner end of the ear canal. On that inner side of the tympanic membrane is an air-filled space called the middle ear cavity. The vibrations of the tympanic membrane are transmitted through the malleus (hammer) incus (anvil) and stapes (stirrup), also called the ossicles. The stapes footplate transmits the vibrations into the inner ear.

3. inner ear:The inner ear has two divisions: one for hearing, the other for balance. The hearing division consists of the cochlea and the nerve of hearing. The cochlea is snail-shaped, bony structure that contains the sensory organ for hearing called the organ of Corti. The organ of Corti releases chemical messengers when the vibrations from the stapes activate its tiny hair cells. These then excite the nerves of hearing which carry sound to the brain.

4. central auditory pathways:The central auditory system is a complex network of neural pathways in the brain that is responsible for sound localization, speech understanding in noisy listening situations and other complex sounds, including music perception.

Types of hearing loss-

CONDUCTIVE HEARING LOSS
Conductive hearing loss is caused by any condition or disease that blocks or impedes the conveyance of sound through the middle ear. The result is a reduction in the sound intensity (loudness) that reaches the cochlea. Generally, the cause of conductive hearing loss can be treated with a complete or partial improvement in hearing.

SENSORINEURAL HEARING LOSS
Sensorineural hearing loss results from inner ear or auditory nerve dysfunction. Often, the cause cannot be determined. It is typically irreversible and permanent. It, too, reduces the intensity of sound, but it might also result in a lack of clarity even when sounds, particularly speech, are loud enough. The treatment for sensorineural hearing loss is amplification through hearing aids.

MIXED HEARING LOSS
A mixed hearing loss is a combination of a conductive and a sensorineural hearing loss. Hearing aids can be beneficial for persons with a mixed hearing loss, but caution should be exercised.

CAUSES OF HEARING LOSS
The main causes of hearing loss are as follows:
Excessive noise (i.e. construction, rock music, gun shot, etc)
Aging (presbycusis)
Infections (otitis media)
Injury to the head or ear
Birth defects or genetics
Ototoxic reaction to drugs or cancer treatment (i.e. antibiotics, chemotherapy, radiation)

>>>Hearing loss simulator<<<

Tinnitus-
Tinnitus is the perception of a sound that has no external source. Some of the more common sounds reported are ringing, humming, buzzing, and cricket-like. It can be constant or intermittent and is heard in one ear, both ears or in the head. Tinnitus can originate in the middle ear (behind the eardrum) or in the sensorineural auditory system.
THE MOST COMMON CAUSES ARE:
Noise exposure (e.g. from shooting or machines at work)
A natural part of the aging process
Head injury (e.g. from a car accident or fall)
As a side effect of medications (e.g. aspirin)

Info from better hearing institute..