WHO updates fact sheet on Deafness and Hearing loss (9 February 2017)

The World Health Organization (WHO) has updated its fact sheet on deafness and hearing loss.

Background information:

Normal hearing refers to the ability to hear thresholds of 25 dB or better in both ears.

A person who is not able to hear as well as someone with normal hearing 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.

‘Deaf’ people mostly have profound hearing loss, which implies very little or no hearing. They often use sign language for communication.

Key Messages:

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 40 decibels (dB) in the better hearing ear in adults and a hearing loss greater than 30 dB in the better hearing ear in children.

The majority of people with disabling hearing loss 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.

Causes of hearing loss

Congenital causes

  • 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 particular drugs during pregnancy, such as aminoglycosides, cytotoxic drugs, antimalarial drugs, and diuretics;
  • severe jaundice in the neonatal period, which can damage the hearing nerve in a newborn infant.

Acquired causes

  • infectious diseases including meningitis, measles and mumps;
  • chronic ear infections;
  • collection of fluid in the ear (otitis media);
  • use of certain medicines, such as those used in the treatment of neonatal infections, malaria, drug-resistant tuberculosis, and cancers;
  • injury to the head or ear;
  • excessive noise, including occupational noise such as that from machinery and explosions;
  • recreational exposure to loud sounds such as that from use of personal audio devices at high volumes and for prolonged periods of time and regular attendance at concerts, nightclubs, bars and sporting events;
  • ageing, in particular due to degeneration of sensory cells; and
  • wax or foreign bodies blocking the ear canal.

Among children, chronic otitis media is a common cause of hearing loss.

60% of childhood hearing loss is due to preventable causes.

Impact of hearing loss

Functional impact

Spoken language development is often delayed in children with unaddressed hearing loss.

Social and emotional impact

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.

Economic impact

WHO estimates that unaddressed hearing loss poses an annual global cost of 750 billion international dollars.

This includes

  • health sector costs (excluding the cost of hearing devices),
  • costs of educational support,
  • loss of productivity, and
  • societal costs.

 

Prevention

Overall, it is suggested that half of all cases of hearing loss can be prevented through public health measures.

In children under 15 years of age, 60% of hearing loss is attributable to preventable causes. This figure is higher in low- and middle-income countries (75%) as compared to high-income countries (49%).

Overall, preventable causes of childhood hearing loss include:

  • Infections such as mumps, measles, rubella, meningitis, cytomegalovirus infections, and chronic otitis media (31%).
  • Complications at the time of birth, such as birth asphyxia, low birth weight, prematurity, and jaundice (17%).
  • Use of ototoxic medicines in expecting mothers and babies (4%).
  • Others (8%)

Some simple strategies for prevention of hearing loss include:

  • immunizing children against childhood diseases, including measles, meningitis, rubella and mumps;
  • immunizing adolescent girls and women of reproductive age against rubella before pregnancy;
  • preventing cytomegalovirus infections in expectant mothers through good hygiene; screening for and treating syphilis and other infections in pregnant women;
  • strengthening maternal and child health programmes, including promotion of safe childbirth;
  • following healthy ear care practices;
  • screening of children for otitis media, followed by appropriate medical or surgical interventions;
  • avoiding the use of particular drugs which may be harmful to hearing, unless prescribed and monitored by a qualified physician;
  • referring infants at high risk, such as those with a family history of deafness or those born with low birth weight, birth asphyxia, jaundice or meningitis, for early assessment of hearing, to ensure prompt diagnosis and appropriate management, as required;
  • reducing exposure (both occupational and recreational) to loud sounds by raising awareness about the risks; developing and enforcing relevant legislation; and encouraging individuals to use personal protective devices such as earplugs and noise-cancelling earphones and headphones.

Identification and management

Early detection and intervention are crucial to 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 programmes can improve the linguistic and educational outcomes for the child.

Children with deafness should be given the opportunity to learn sign language along with their families.

Pre-school, school and occupational screening for ear diseases and hearing loss is an effective tool for early identification and management of hearing loss.

People with hearing loss can benefit from the use of hearing devices, such as hearing aids, cochlear implants, and other assistive devices. They may also benefit from speech therapy, aural rehabilitation and other related services. However, global production of hearing aids meets less than 10% of global need and less than 3% of developing countries’ needs. The lack of availability of services for fitting and maintaining these devices, and the lack of batteries are also barriers in many low-income settings.

Useful Links:

Link to the updated fact sheet:

http://www.who.int/mediacentre/factsheets/fs300/en/

Link to WHO page with details regarding estimates of deafness and hearing loss:

http://www.who.int/pbd/deafness/estimates/en/

Link to summary of ‘WHO Training resource on Primary Ear and Hearing Care’ (English) [PDF]:

http://www.who.int/pbd/deafness/activities/hearing_care/summary.pdf?ua=1

Link to WHO’s Primary Ear and Hearing Care Training Resource: Basic Level (English) [PDF]:

http://www.who.int/pbd/deafness/activities/hearing_care/basic.pdf?ua=1

Link to WHO’s Primary Ear and Hearing Care Training Resource: Trainer’s Manual- Intermediate Level (English) [PDF]:

http://www.who.int/pbd/deafness/activities/hearing_care/trainer.pdf?ua=1

Link to WHO’s Primary Ear and Hearing Care Training Resource: Student’s Workbook- Intermediate Level (English) [PDF]:

http://www.who.int/pbd/deafness/activities/hearing_care/student.pdf?ua=1

Link to WHO’s Primary Ear and Hearing Care Training Resource: Advanced Level (English) [PDF]:

http://www.who.int/pbd/deafness/activities/hearing_care/advanced.pdf?ua=1

Link to WHO’s Question and Answer page on Ear care for children:

http://www.who.int/features/qa/81/en/

Link to WHO’s Question and Answer page on Age-related hearing loss (presbycusis):

http://www.who.int/features/qa/83/en/

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s