Deafness is the partial or total inability to hear. The two principal types of deafness are conduction deafness and nerve deafness. In conduction deafness, there is interruption of the sound vibrations in their passage from the outer world to the nerve cells in the inner ear. The obstacle may be earwax that blocks the external auditory channel, or stapes fixation, which prevents the stapes (one of the minute bones in the middle ear) from transmitting sound vibrations to the inner ear. In nerve deafness, some defect in the sensory cells of the inner ear (e.g., their injury by excessive noise) or in the vestibulocochlear nerve prevents transmission of sound impulses from the inner ear to the auditory center in the brain. Deafness at birth is nearly always of the nerve type and cannot be improved by medical means.

Causes: The genetic causes of deafness that people are born with include Down syndrome, CHARGE Syndrome, Waardenburg Syndrome, and Treacher Collins Syndrome.

Down syndrome- a chromosomal condition caused by the presence of all or part of an extra 21st chromosome. Tests show that 38%-78% of the children with Down syndrome develop hearing losses at young ages.
CHARGE syndrome- a syndrome caused by a genetic disorder. Some of the effects of it are coloboma, congenital heart defect, and hearing loss.
Waardenburg Syndrome- is a rare genetic disorder most often characterized by varying degrees of deafness.
Treacher Collins Syndrome: is a rare autosomal dominant congenital disorder characterized by craniofacial deformities, such as absent cheekbones. This also results in abnormal shape of the inner ear bones, hence resulting in possible hearing difficulties.

Benefits and Limitations:
Identification: Common indications for a hearing evaluation include
  • speech delay,
  • frequent or recurrent ear infections,
  • a family history of hearing loss (hearing loss can be inherited),
  • syndromes known to be associated with hearing loss (for example, Down syndrome, the Alport syndrome, and Crouzon syndrome),
  • infectious diseases that cause hearing loss (for example, meningitis, measles, and cytomegalovirus [CMV] infection)
  • medical treatments that may have hearing loss as a side effect, including some antibiotics and some chemotherapy agents,
  • poor school performance, and
  • diagnosis of a learning disability or other disorder, such as autism or pervasive developmental disorder (PDD).

Gene therapy:A study approximately 7 years ago successfully achieved the regrowth of cochlea cells in guinea pigs. However, the regrowth of cochlear hair cells does not imply the restoration of hearing sensitivity as the sensory cells may or may not make connections with neurons that carry the signals from hair cells to the brain. A 2008 study has shown that gene therapy targeting Atoh1, a protein, can cause hair cell growth and attract neuronal processes in developing mice. It is hoped that a similar treatment will one day ameliorate hearing loss in humans.


How hearing impairment is treated will depend on the original cause of the condition. For people with sensorineural* hearing loss, the condition is permanent since once the sensitive hair cells in the cochlea are damaged, they cannot be repaired and remain damaged for the rest of a person’s life. However, if your hearing is impaired, various treatment methods can improve your quality of life.

A hearing aid does not cure a hearing impairment, but it increases the volume of sound entering your ear so that you may be able to hear things more clearly. Modern hearing aids are very small and discreet and can be worn inside your ear. The microphone picks up sound which is made louder by an amplifier. There are many different types of hearing aids. Some of them are:Behind-the-ear, In-the-ear, In-the-canal, completely in-the-canal, Bone Anchored Hearing Aids (requires an operation), and Disposable hearing aids (for people with mild hearing loss).

*sensorineural- is a type of hearing loss in which the root cause lies in the vestibulocochlear nerve which is responsible for transmitting sound and balancing information from the inner ear to the brain.


Cochlear implants are small hearing devices that are fitted behind your ear during surgery. They have an external sound processor and internal parts including a receiver coil, an electronics package and a long wire with electrodes on it. The electrode array is fed into the cochlea and stimulates the hearing nerve. The processor takes in sound, analyses it and then converts it to signals which are transmitted along the electrode array into the cochlea. This means that cochlear implants are only suitable for people whose hearing nerves are functioning normally.
Sometimes, hearing impairment can affect your speech as well as your ability to understand other people. For people who experience hearing loss after they have learnt to talk, lip-reading can be a very useful skill. Lip-reading is where you watch a person’s mouth movements while they are speaking in order to understand what they are saying. Those who are born with a hearing impairment often learn sign language, such as British Sign Language (BSL), which is a form of communication that uses hand movements and facial expressions to convey meaning (Hearing Impairment).
A person diagnosed with deafness is only limited by their hearing. Their other senses will react to things as others' can, and may even heighten. Communication would be difficult with a deafened person, because to respond, the other person would have to understand sign language to make out what they're saying. A person would also need some type of assistant to help them, whether it's just a walk in the park or if the deafened person has a medical emergency. Deafness also limits the level you can work at and the kind of jobs you can not only apply for but get. It jeopardizes the types of salary an individual can receive, causing some people to lose up to $440,000 in their careers (Supplement Content).
Areas of Interaction:
Social: If a child is deaf from birth (pre-lingual hearing-impaired) the issues are different to those who have become deaf after learning to speak (post-lingual hearing-impaired). The situation is also different if the child is born into a deaf or hearing-impaired family as opposed to a hearing family. The socialization of the child (how they learn to function in society) will be influenced by this family situation and how the parents choose to manage the hearing impairment.
This extends to educational opportunities as well. The aim of integrating hearing-impaired students in mainstream schools is to enhance their socialization into the hearing community, but many in the Deaf community believe it accentuates differences and students would be better served in a specialist education center.
Economic: Studies have shown that severe to profound hearing loss is expected to cost society $297,000 over the lifetime of an individual. Most of these losses (67%) are due to reduced work productivity, although the use of special education resources among children contributes an additional 21%. Lifetime costs for those with prelingual* onset exceed $1 million. People who experience severe to profound hearing loss before retirement age lose between $220,000 and $440,000 in earnings over their working life, depending on when the onset of hearing loss occurs (Supplement Content).
*Prelingual deafness- those who are born with insufficient hearing to acquire speech normally.
Cultural:There is a deaf community with its own language and culture, so there is a cultural frame in which to be deaf is not to be infirm or disabled. To the contrary, it is an asset of and for the deaf community to be deaf in behavior, values, knowledge and fluency in sign language. It is within this community bonded by shared culture and language that lives defined by diagnosis, disadvantages imposed by majority beliefs and practices, and disabilities tied to inappropriate models of language and social enrichment. The experiences of a language minority such as the deaf thus seen, amounts to a social disadvantage no more or less troubling than it would be for any language minority. In terms of its effect on mental health, deaf cultural attitudes conclude that a minority language group's disadvantages are preferred to a lifetime of viewing one's self or one's group as infirm or disabled.
Ethical: About 90% of those who identify themselves as being culturally Deaf choose a deaf partner. Sometimes termed "assortative mating," this process is based on linguistic, social, and cultural similarities. Many deaf couples have no preference for either deaf or hearing children, but would welcome the birth of a deaf child to share their language and culture.

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