Hearing loss is defined as hearing at thresholds greater than 20dB in the better ear while deafness is hearing at thresholds above 95dB on both ears. Hearing loss greater than 35 decibels (dB) in the better-hearing ear is referred to as disabling hearing loss. Hearing loss; measured in decibels, could classified as mild, moderate, moderately severe, severe or profound. This could affect one ear or both ears. Hearing thresholds of 25dB or better in one ear and greater than 35dB in the other ear are termed unilateral hearing loss. Hearing loss results in difficulties engaging in conversational speech or even hearing loud sounds.
People with hearing loss ranging from mild to severe are referred to as Hard of hearing. They can communicate using spoken language but may benefit from hearing aids, cochlear implants, and other assistive devices as well as captioning. Deaf people have very minimal or no hearing at all. They rely on sign language, assistive listening technology and captioning to communicate.
Grading of hearing loss and functional consequence of each grade (From World Report on Hearing
Regional situation
Hearing loss is on the rise globally. Up to 80% of people with hearing loss live in low- and middle-income countries. In 2023, estimates showed that there are 40 million people Africa with hearing loss. This projected to rise to 54 million people in 2030 and 97 million people with hearing loss in 2050.
Hearing loss may occur at any point across the life course of an individual. Some causes of hearing loss tend to affect individuals at a certain stage in their life course beginning from the prenatal period, perinatal period, childhood, and adolescence or even in adulthood and older age. However, some factors causing hearing loss may occur at any stage across the life course. Up to 60% of causes of hearing loss and deafness are preventable using simple public health interventions at the community level.
The key challenges to curbing the rise in the prevalence of hearing loss is lack of health system capacity for provision of integrated ear and hearing care (EHC) across the life course, and societal misperceptions and stigmatizing mindsets that influence care seeking causing those affected to either not seek treatment at all, to seek traditional treatment which usually causes more harm or to not utilise recommended treatment options such as hearing aids due to stigma.
The impact of hearing loss is far reaching. At an individual level, unaddressed hearing loss negatively impacts communication and speech development, academic achievements and prospects of gainful employment, causes social isolation and stigma as well as overall quality of life of living with disability. Failing to address hearing loss costs African economies USD27.1 billion mainly due to loss of productivity and social isolation attributed to unaddressed hearing loss.
An individual can develop hearing impairment at any time across the lifespan. However, there are periods in the life course when people are more susceptible to developing hearing loss from specific causes.
Prenatal period
- Genetic factors including hereditary & non-hereditary hearing loss
- Intrauterine infections such as Rubella, Cytomegalovirus (CMV)
- Herpes simplex virus type 1 and 2
- Human immunodeficiency virus
- Syphilis
Perinatal period
- Birth asphyxia (a lack of oxygen at the time of birth
- Hyperbilirubinemia (severe jaundice in the neonatal period)
- Low-birth weight
- Other perinatal morbidities and their management, ototoxicity
- Noise in NICU
Childhood and adolescence
- Chronic ear infections
- Infections common in childhood e.g. Measles, Meningitis, Mumps
Adulthood and older age
- Chronic diseases
- Smoking
- Otosclerosis
- Age-related sensorineural degeneration
- Sudden sensorineural hearing loss
Factors across the life course
- Impacted ear wax
- Trauma to the ear or head
- Loud noise/loud sounds
- Ototoxic medicines
- Work-related ototoxic chemicals
- Nutritional deficiencies
- Viral infections and other ear conditions
- Delayed onset or progressive genetic hearing loss
Congenital causes may lead to hearing loss being present at or acquired soon after birth. 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 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 may lead to hearing loss at any age, such as:
- 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.
Impact of hearing loss on an individual
- Poor performance in schools
- Listening and communication
- Language and speech development
- Cognition
- Education
- Employment and financial wellbeing
- Social isolation and loneliness
- Mental health
- Interpersonal relationships
- Identity and stigma
- Economic costs of unaddressed hearing loss
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.
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.
How can we address the problem?
Over 70% of causes of hearing loss in Africa are preventable through simple and cost-effective evidence based public health measures. IP-EHC should be integrated into the primary health care system and primary healthcare workers be empowered to make diagnosis and treat ear and hearing disorders as part of continuum of care for other conditions, so no one is left behind.
Implementation of H.E.A.R.I.N.G interventions
- Hearing screening and intervention
- Ear disease prevention and management
- Access to technologies
- Rehabilitation services
- Improved communication
- Noise reduction
- Greater community engagement
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.
Making properly-fitted, affordable hearing aids and cochlear implants 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. Encouraging organizations of people with hearing loss, parents and family support groups; and strengthening human rights legislation can also help ensure better inclusion for people with hearing loss.
WHO assists Members States in developing programmes for ear and hearing care that are integrated into the primary health-care system of the country. WHO’s work includes:
Raising awareness among policy makers, key stakeholders and the general public on the burden of hearing loss, it’s impact on the affected person, the society and the economy through strategies such as the World Hearing Day.
Advocating for integrated people centred ear and hearing care (IPC-EHC) strategies in the health care system beginning with empowering the community level to perform early identification and management ear diseases.
- Integrated People Centred Ear and Hearing Care: Policy Brief
- Basic Ear and Hearing Care Resource
- Primary Ear and Hearing Care Training Manual
Supporting ministries of health to include EHC indicators in the Health Management System and encourage population surveys to gather data on hearing loss and ear disease to provide an evidence-based case for the need to elevate EHC in health planning and financing.
- Situation analysis tool
- Planning & monitoring of national strategies
- Indicators for monitoring provision of services
Supporting capacity building of human resources for ear and hearing care through increasing training opportunities for different cadre and empowering the PHC system to provide EHC services.
Strengthening EHC service delivery including screening programs for all at risk individuals across the life course, management of disease and ensuring access to affordable and quality hearing devices and other rehabilitation and communication strategies.
- Survey handbook
- Hearing screening: considerations for implementation
- Deafness and hearing loss: Hearing checks and the hearWHO app
- HearWHO app
Raising awareness on avoidable causes of hearing loss and draft adopt and implement legislation to protect the public with regards to noise, recreational and occupational noise-induced hearing loss as well as ototoxicity.
