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Hearing Impairment: Deaf and Hearing Loss Information

Disabled World: Revised/Updated: 2019/08/28

Synopsis: Information on hearing and deafness including common auditory system conditions and sign language communication. Hearing loss can occur on only one side (unilateral) or on both (bilateral) The commonest cause of hearing loss is aging, and three-quarters of people who are deaf are aged over 60.

Main Document

Hearing is one of the traditional five senses. It is the ability to perceive sound by detecting vibrations via an organ such as the ear. The inability to hear is called deafness. A hearing impairment or hearing loss is a full or partial decrease in the ability to detect or understand sounds. Caused by a wide range of biological and environmental factors, loss of hearing can happen to any organism that perceives sound.

Hearing loss, deafness, hard of hearing, anacusis, or hearing impairment, is defined as a partial or total inability to hear. In children it may affect the development of language and can cause work related difficulties for adults. Hearing loss is caused by many factors, including: genetics, age, exposure to noise, illness, chemicals and physical trauma.

Hearing loss can also be classified based on which portions of the hearing system (auditory system) are affected. When the nervous system is affected, it is referred to as sensorineural hearing loss. When the portions of the ear that are responsible for transmitting the sound to the nerves are affected, it is referred to as conductive hearing loss.

A sensorineural hearing loss is due to insensitivity of the inner ear, the cochlea, or to impairment of function in the auditory nervous system. It can be mild, moderate, severe, or profound, to the point of total deafness. This is classified as a disability under the ADA and if unable to work is eligible for disability payments.

There are two main types of hearing loss:

Two persons with the same severity of hearing loss will experience it quite differently if it occurs early or late in life. Furthermore, a loss can occur on only one side (unilateral) or on both (bilateral). Hearing loss is categorized by its severity and by the age of onset and may be ranked as mild, moderate, moderately severe, severe or profound:

People who are severely deaf rely a lot on lip-reading, even with a hearing aid. Profoundly deaf people can also use sign language to communicate. Hearing impaired persons with partial loss of hearing may find that the quality of their hearing varies from day to day, or from one situation to another or not at all. They may also, to a greater or lesser extent, depend on both hearing-aids and lip-reading.

Any form of communication between people is a two way street. It is very important then to determine how a deaf person prefers to communicate. There are a number of options available to them such as sign language, lip reading or using text. There will be a way of making a connection. It may sometimes be difficult or awkward but the effort is well worth it.

The commonest cause of hearing loss is aging, and three-quarters of people who are deaf are aged over 60. At around 20 years of age, our hearing starts a gradual decline. Higher frequencies are usually the first to go. This age-related hearing loss is normal and doesn't lead to total loss of hearing. Age-related hearing loss (presbycusis) typically begins with the loss of higher frequencies, so that certain speech sounds - such as 's', 'f' and 't' - end up sounding very similar. This means the older person can hear, but not always understand.

Many people who are deaf consider spoken language their primary language and consider themselves "hard of hearing". How one classifies themselves relative to hearing loss or deafness is a very personal decision and reflects much more than just their ability to hear.

Basic labeled illustration showing the structure of the human ear, detailing the parts of the outer, middle, and inner ear.
Basic labeled illustration showing the structure of the human ear, detailing the parts of the outer, middle, and inner ear.

Deaf Culture

Describes the social beliefs, behaviors, art, literary traditions, history, values, and shared institutions of communities that are affected by deafness and which use sign languages as the main means of communication.

When used as a cultural label especially within the culture, the word deaf is often written with a capital D and referred to as "big D Deaf" in speech and sign. When used as a label for the audiological condition, it is written with a lower case d.

Facts and Statistics

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