Hearing Impairment: Deaf and Hearing Loss Information


Information on hearing and deafness including common auditory system conditions and sign language communication.

Definition: Defining the Meaning of Hearing Loss

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.

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.

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 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.

  • One happens when your inner ear or auditory nerve is damaged. This type is permanent.
  • The other kind happens when sound waves cannot reach your inner ear due to ear wax build up, fluid or a punctured eardrum.

Hearing loss is categorized by its severity and by the age of onset.

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 impairment may be ranked as mild, moderate, moderately severe, severe or profound:

  • Mild:
    • for adults: between 26 and 40 dB HL
    • for children: between 20 and 40 dB HL
  • Moderate: between 41 and 54 dB HL
  • Moderately severe: between 55 and 70 dB HL
  • Severe: between 71 and 90 dB HL
  • Profound: 91 dB HL or greater
  • Totally Deaf: Have no hearing at all.

Hearing loss can be inherited.

Both dominant gene and recessive genes exist which can cause mild to profound impairment. If a family has a dominant gene for deafness it will persist across generations because it will manifest itself in the offspring even if it is inherited from only one parent. It is estimated around half of all deafness and hearing impairment can be prevented.

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.

Hearing Impairment Awareness Dates

Gold and silver awareness ribbonThe Gold and Silver awareness ribbon represents hearing impairments including Tinnitus and Meniere Disease.

Canada - May is Speech and Hearing Awareness Month.

USA - October Is National Audiology Awareness Month. AAA is dedicated to increasing public awareness of audiology and the importance of hearing protection.

UK - September is Hearing Awareness Month

Quick Facts: Hearing Loss

  • Some medications may reversibly affect hearing. This includes some diuretics, aspirin and NSAIDs, and macrolide antibiotics.
  • The term hearing impaired is more likely to be used by people with a less than severe hearing loss and people who have acquired deafness in adulthood rather than by those who have grown up deaf.
  • There is a progressive loss of ability to hear high frequencies with increasing age known as presbycusis. For men, this can start as early as 25 and women at 30, but may even affect teenagers and children.
  • Hearing loss can be inherited. Around 75-80% of all cases are inherited by recessive genes, 20 to 25% are inherited by dominant genes, 1 to 2% are inherited by X-linked patterns, and fewer than 1% are inherited by mitochondrial inheritance.
  • Members of the deaf community tend to view deafness as a difference in human experience rather than a disability. A positive attitude toward being deaf is typical in deaf cultural groups. Deafness is not generally considered a condition that needs to be fixed.
  • Deaf culture is recognized under article 30, paragraph 4 of the United Nations Convention on the Rights of Persons with Disabilities, which states that "Persons with disabilities shall be entitled, on an equal basis with others, to recognition and support of their specific cultural and linguistic identity, including sign languages and deaf culture."

Statistics: Hearing Impairment

Over 37 million adults and over 1 million children in the United States suffer from some degree of hearing loss.

In the U.K. around 840 babies are born with significant deafness each year. About one in 1,000 children is deaf at three years old and about 20,000 children aged up to 15 are moderately to profoundly deaf.

Latest Hearing Loss and Deafness Publications

Study raises questions about the role of experience in processing sensory information, and could point the way toward potential new avenues for intervention in deafness.

Long lasting and loud sounds can damage sensitive structures in the inner ear and cause noise induced hearing loss (NIHL).

Investigating whether early exposure to sign language can forestall cognitive issues in deaf children.

Improving hearing for people with hearing loss, not helped by hearing aids, using hybrid cochlear implant devices.

New studies reveal that women under the age of 70 are particularly susceptible to hearing loss related depression.

Information regarding sensorineural deafness and medications that can damage the human ear resulting in hearing loss, balance disorders, or ringing in the ear.

Information regarding Misophonia a rare sound sensitivity disorder characterized by an extreme aversion to certain sounds.

Educating people about services issues and obstacles deaf and hard of hearing individuals face every day.

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