|The Royal Academy of Science International Trust
|at the heart of Science, Education, Economy, Arts & Sustainable Development
|The World Health Organization (WHO) Published a Fact Sheet about Deafness and
hearing loss in the World. The Fact Sheet, N°300 - updated in February 2013, reveals
the following Key facts
- 360 million people worldwide have disabling hearing loss.
- Hearing loss may be inherited, caused by maternal rubella or complications at
birth, certain infectious diseases such as meningitis, chronic ear infections,
use of ototoxic drugs, exposure to excessive noise and ageing.
- Half of all cases of hearing loss are avoidable through primary prevention.
- People with hearing loss can benefit from devices such as hearing aids,
assistive devices and cochlear implants, and from captioning, sign language
training, educational and social support.
- Current production of hearing aids meets less than 10% of global need.
Through its MUTE International Program, RASIT supports the
World Health Organization initiative in assisting countries in
developing programs for primary ear and hearing care that are
integrated into the primary health-care system of the country.
|Removing barriers to create an inclusive and
accessible society for all
Save the Date
International Day of Persons with Disabilities
|Deafness and Hearing Loss Around the World
Over 5% of the world’s population – 360 million people – has disabling hearing loss
(328 million adults and 32 million children). Disabling hearing loss refers to hearing
loss greater than 40dB in the better hearing ear in adults and a hearing loss greater
than 30dB in the better hearing ear in children. The majority of these people live in
low- and middle-income countries.
Approximately one-third of people over 65 years of age are affected by disabling
hearing loss. The prevalence in this age group is greatest in South Asia, Asia Pacific
and sub-Saharan Africa.
In a very simple language, this is how we hear:
The ear is divided into three parts leading up to the brain (the outer,
the middle, and the inner ear). Each part has its own function that
help converting the external waves, entering the ear, into a form that
the brain can understand, this form is called electrical impulses.
- The outer part of the ear collects the sound waves, and
direct them into the ear canal
- The ear canal carries the sound to the eardrum (Tympanic
membrane), this sound causes the latter to vibrate.
- Vibrations are picked up by the bones (malleus, incus and
stapes) available in the middle part of the ear.
- Vibrations then pass through the oval window to the
cochlea, and cause the fluid inside the inner part of the ear
to be in motion. Special nerve cells then convert these
sound waves into electrical impulses.
- The auditory nerve sends these electrical impulses to the
brain where they are translated onto understandable sound.
|Do you Know Causes of
Hearing Loss and Deafness
A person who is not able to hear as well as someone with normal hearing – hearing
thresholds of 25dB or better in both ears – is said to have hearing loss. Hearing loss may
be mild, moderate, severe or profound. It can affect one ear or both ears, and leads to
difficulty in hearing conversational speech or loud sounds.
‘Hard of hearing’ refers to people with hearing loss ranging from mild to severe. They
usually communicate through spoken language and can benefit from hearing aids,
captioning and assistive listening devices. People with more significant hearing losses
may benefit from cochlear implants.
‘Deaf’ people mostly have profound hearing loss, which implies very little or no hearing.
They often use sign language for communication.
Causes of hearing loss and deafness
The causes of hearing loss and deafness can be divided into congenital causes and
Congenital causes lead to hearing loss being present at or acquired soon after birth.
- Congenital causes
Hearing loss can be caused by hereditary and non-hereditary genetic factors or by certain
complications during pregnancy and childbirth, including:
- maternal rubella, syphilis or certain other infections during pregnancy;
- low birth weight;
- birth asphyxia (a lack of oxygen at the time of birth);
- inappropriate use of ototoxic drugs (such as aminoglycosides, cytotoxic drugs,
antimalarial drugs and diuretics) during pregnancy; and
- severe jaundice in the neonatal period, which can damage the hearing nerve in a
Acquired causes lead to hearing loss at any age.
- Infectious diseases such as meningitis, measles and mumps can lead to hearing
loss, mostly in childhood, but also later in life.
- Chronic ear infection, which commonly presents as discharging ears, can lead to
hearing loss. In certain cases this condition can also lead to serious, life-
threatening complications, such as brain abscesses or meningitis.
- Collection of fluid in the ear (otitis media) can cause hearing loss.
- Use of ototoxic drugs at any age, such as some antibiotic and antimalarial
medicines for example, can damage the inner ear.
- Head injury or injury to the ear can cause hearing loss.
- Excessive noise, including working with noisy machinery, and exposure to loud
music or other loud noises, such as gunfire or explosions, can harm a person’s
- Age-related hearing loss (presbycusis) is caused by degeneration of sensory cells.
- Wax or foreign bodies blocking the ear canal can cause hearing loss at any age.
Such hearing loss is usually mild and can be readily corrected.
Among children, chronic otitis media is the leading cause of hearing loss.
One of the main impacts of hearing loss is on the individual’s ability
to communicate with others. Spoken language development is often
delayed in children with deafness.
Hearing loss and ear diseases such as otitis media can have a
significantly adverse effect on the academic performance of
children. However, when opportunities are provided for people with
hearing loss to communicate they can participate on an equal basis
with others. The communication may be through spoken/ written
language or through sign language.
Social and emotional impact
Limited access to services and exclusion from communication can
have a significant impact on everyday life, causing feelings of
loneliness, isolation and frustration, particularly among older people
with hearing loss.
If a person with congenital deafness has not been given the
opportunity to learn sign language as a child, they may feel excluded
from social interaction.
In developing countries, children with hearing loss and deafness
rarely receive any schooling. Adults with hearing loss also have a
much higher unemployment rate. Among those who are employed,
a higher percentage of people with hearing loss are in the lower
grades of employment compared with the general workforce.
Improving access to education and vocational rehabilitation
services, and raising awareness especially among employers,
would decrease unemployment rates among adults with hearing
In addition to the economic impact of hearing loss at an individual
level, hearing loss substantially affects social and economic
development in communities and countries.
Half of all cases of hearing loss can be prevented through primary prevention. Some simple
strategies for prevention include:
- immunizing children against childhood diseases, including measles, meningitis,
rubella and mumps;
- immunizing adolescent girls and women of reproductive age against rubella before
- screening for and treating syphilis and other infections in pregnant women;
- improving antenatal and perinatal care, including promotion of safe childbirth;
- avoiding the use of ototoxic drugs, unless prescribed and monitored by a qualified
- referring babies with high risk factors (such as those with a family history of
deafness, those born with low birth weight, birth asphyxia, jaundice or meningitis)
for early assessment of hearing, prompt diagnosis and appropriate management,
as required; and
- reducing exposure (both occupational and recreational) to loud noises by creating
awareness, using personal protective devices, and developing and implementing
Hearing loss due to otitis media can be prevented by healthy ear and hearing care
practices. It can be suitably dealt with through early detection, followed by appropriate
medical or surgical interventions.
We are the SAME
A large percentage of people living with hearing loss can benefit from early identification and
intervention, and appropriate management.
Early detection and intervention is the most important factor in minimizing the impact of
hearing loss on a child’s development and educational achievements. In infants and young
children with hearing loss, early identification and management through infant hearing
screening programs can improve the linguistic and educational outcomes for the child.
Children with deafness should be given the opportunity to learn sign language along with
Pre-school, school and occupational screening for ear diseases and hearing loss can also
be effective for early identification and management of hearing loss.
People with hearing loss can benefit from the use of hearing devices, such as hearing aids,
assistive listening devices and cochlear implants. They may also benefit from speech
therapy, aural rehabilitation and other related services. However, current production of
hearing aids meets less than 10% of global need. In developing countries, fewer than one
out of 40 people who need a hearing aid have one. The lack of availability of services for
fitting and maintaining hearing aids, and the lack of batteries are also barriers in many low-
income settings. Making properly-fitted, affordable hearing aids and providing accessible
follow-up services in all parts of the world will benefit many people with hearing loss.
People who develop hearing loss can learn to communicate through development of lip-
reading skills, use of written or printed text, and sign language. Teaching in sign language
will benefit children with hearing loss, while provision of captioning and sign language
interpretation on television will facilitate access to information.
Officially recognizing national sign languages and increasing the availability of sign
language interpreters are important actions to improve access to sign language services.
Human rights legislation and other protections can also help ensure better inclusion for
people with hearing loss.
|Do you Know
Identification & management of Hearing Loss
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