Early intervention is crucial to minimize the
adverse impact of hearing loss on language
and cognitive development.

In 2019, the global number of years lived with disability (YLDs) attributable to hearing
loss was 43.5 million (95% UI 29.7–61.8). This number has increased by 73% since
1990 (25.0 million YLDs). Age-related hearing loss was the third largest source of
global YLDs in 2019 and the leading source for adults older than 70 years of age.11
Sixty-five per cent of disability caused by hearing loss is attributed to moderate or
higher grades of hearing loss. Irrespective of the severity of hearing loss or the
audiological profile, the extent to which hearing loss impacts people’s lives depends
on whether it is addressed with effective clinical or rehabilitative interventions (75, 123,
159), and the extent to which the environment is responsive to the needs of people
with hearing loss (75, 158). The impact can also be influenced by other co-existing
functional limitations such as vision impairment, autism or developmental disabilities.
Dual sensory loss in the form of deaf-blindness is estimated to affect as many as 0.2–
2% of the global population at all ages (159). Implications of its impact are highlighted
in Box 1.2.

Box 1.2 Dual sensory loss: deaf-blindness (160, 161)

Deaf-blindness involves dual sensory loss of vision and hearing to varying
degrees. Although affecting all ages, deaf-blindness occurs most commonly in
elderly people. Thus, as the global population ages, it has become increasingly
prevalent. Those with deaf-blindness commonly report an overall low quality
of life. They often feel socially isolated due to communication difficulties and
lack of public acceptance; have reduced participation in social events due to
mobility challenges; have difficulties with daily functioning; experience feelings
of loneliness, anger, frustration, depression, insecurity, uncertainty about the
future; worthlessness; and face stigma on a daily basis. When compared with
other disabilities, individuals with deaf-blindness are more likely to live in
poverty and be unemployed, with lower educational outcomes.



When unaddressed, hearing loss impacts many aspects of life:
The greatest challenge for people with unaddressed hearing loss is in maintaining
communication with others in their environment. The extent of the problem varies
depending on the determinants listed above and may range from a person finding it
difficult to listen to quiet speech or speech in noisy surroundings, to inability to hear
even loud warning sounds including alarms. People with hearing loss often need
to ask others to repeat themselves and may find it difficult to communicate in the
workplace or to carry on a routine conversation. These difficulties have been further
exacerbated as a result of the essential preventive measures against COVID-19 (163).
While masks and social distancing are undisputed allies in the fight against the virus,
these create additional obstacles for people with hearing loss, who often rely on lip
reading and other facial and physical clues to communicate (163).


The development of spoken language in children is directly related to their hearing
ability. Most studies conducted on children with hearing loss show that they
experience delayed speech and language development which are likely to continue
into adulthood (154, 164). The grade of impairment is proportionate to difficulties
in speech perception and language deficits (165). However, even mild or unilateral
hearing losses, which are commonly overlooked,
have an adverse impact on speech and language development in children (154, 166–168). The language
and speech outcomes of children with hearing loss are also greatly affected by the age at which intervention
is commenced, with outcomes being more successful for children identified before six months of age and
followed by prompt intervention (169). The timing of intervention also affects developmental outcomes, as
sensory deprivation in early years of life is commonly linked with developmental problems (170).
Language is essential not only as a means for communication, but also as contributor for cognitive
development, a tool for education, and the basis for social relationships. Hence, access to language is
critical (171); when deaf infants are unable to access language stimulation early in life, it poses a challenge
for their overall development (171).

In children (and also adults) that develop hearing loss
after speech development, hearing loss can affect the
quality of speech, which may be muffled and unclear
if it is left untreated.
In those with sensorineural hearing loss, such as agerelated
hearing loss, a common tendency to speak
loudly has been observed, which can create further
difficulties within families (154).


Language deprivation risks delayed cognitive
development in children, which can be avoided if they
receive suitable intervention during the initial years of
life (170, 172). Even unilateral hearing loss, occurring
in children, affects the development of cognitive skills
(168). The impact on cognition is not limited to children
but is clearly evident in adult-onset hearing loss as
well. Hearing loss is the largest potentially modifiable
risk factor for age-related dementia (173, 174).


Hearing loss can have a long-lasting impact on
the academic outcomes of an individual. Unless
addressed in a timely manner, those with hearing
loss have reduced school performance, slower
progression through the academic system, a greater
risk of dropping out of school, and lower likelihood of
applying for higher education, compared with their
hearing peers (181–183).


An association between hearing loss and employment
in adults is evident. Students with hearing loss often
demonstrate a lack of career-planning and decision-making which are
required for success in the workplace (182, 183). Overall, adults with
hearing loss have increased odds of unemployment or underemployment (184–186).
In northern Finland, a longitudinal study showed that those aged 25 years, with
clinically measured hearing loss, were twice as likely to be unemployed as those

of the same age with normal hearing (182). When
employed, people with hearing loss often earn lower
wages and retire earlier than their hearing peers
(184, 187).


Hearing loss contributes to both social isolation and
loneliness at all ages, more specifically in women and
older adults (188, 189), possibly because of decreased
participation in activities, or by having a smaller social network. This is observed
especially in places where access to ear and hearing care is limited (190). The
impaired ability to comprehend auditory information and maintain conversations
(191) may lead to avoidance of potentially embarrassing social situations by the
affected persons (192). Hence, people with hearing loss, particularly those who do
not use hearing aids, show elevated levels of loneliness (188, 193, 194).
Social isolation and loneliness due to hearing loss can have important implications
for the psychosocial and cognitive health of older adults. Lack of engagement and
feeling lonely may mediate the pathway linking hearing loss and cognitive decline
(195, 196). Furthermore, both can contribute to worsened mental health, leading
to experience of depression and distress (189, 197, 198).


Across the life course, people with hearing loss commonly have higher rates of
depression and report lower quality of life compared with their hearing peers (199–
201). Social withdrawal and altered social interactions are frequently observed in
persons with hearing loss, as well as feelings of embarrassment, rejection and
anxiety (162). Often, during conversation, their communication partners experience
frustration and anger (162).


Over 90% of deaf children are born to hearing parents who most often have no fully
effective means to communicate with their child (202, 203). A number of studies
report that parents have difficulties developing meaningful communication with their
child with hearing loss, and in managing the child’s behaviour, especially if they have
other conditions such as autism spectrum disorders (204). In adults, hearing loss
can have a negative impact on personal relationships resulting in communication
difficulties, misunderstandings and conflict (162). The effect is evident both for the
person with hearing loss as well as their communication partners.


Hearing loss among children, adolescents and adults is frequently linked with feelings
of inadequacy and low self-esteem (162, 207). People with hearing loss, even when it
is addressed, may commonly reflect the stigma that is associated with hearing loss
and the use of hearing devices (162) and try to hide their impairment. Many choose
not to use hearing aids due to prejudiced mindsets and ageist stereotypes (208).


The majority of children who are deaf or hard of hearing are born to parents of
normal hearing (202, 203). In the USA, for example, only around 4% of deaf or hard of-
hearing infants have deaf parents; a further 4% have one parent with hearing loss.
Parents with a deaf or hard-of-hearing child commonly experience higher levels of
emotional and physical strain than other parents; their career may be compromised
to take care of their child full time, and sometimes they may have to relocate to be
closer to the required services (204).
The impact on families, especially on communication partners, is also noteworthy, as
they may experience reductions in social functions due to participation restrictions
related to the partner’s hearing loss; increased stress related to communication;
and reduced satisfaction within the relationship (118, 162).


Beyond financial hardships at the individual level, hearing loss has a considerable
economic impact on society as a whole. WHO data reveal that the overall global cost
of unaddressed hearing loss is greater than $ 980 billion annually (see Figure 1.9).
These include costs related to:

  •  The health-care sector: these are estimated to be around $ 314 billion and include
    health-care costs for children and adults posed by failing to address hearing loss.
    They do not include costs for the provision of services and rehabilitation.
  • The educational sector: a conservative estimate of the cost for providing support
    to children (i.e. those aged 5–14 years) with unaddressed hearing loss is nearly
    $ 27 billion. This assumes that only children with at least moderately severe
    hearing loss (i.e. a hearing level greater than 50 dB in the better hearing ear)
    require educational support.
  • Loss of productivity: costs related to unemployment
    and premature retirement among people with
    hearing loss is conservatively estimated as
    $ 182.5 billion annually.
  • Societal costs: the result of social isolation, communication difficulties and stigma add a
    further $ 456.5 billion each year. These costs are calculated on the basis of the monetary value
    attached to avoidance of a year lived with disability and draw upon disability-adjusted life years (DALYs) attributed to hearing loss.

It is also important to note that 53% of all costs are attributed to low- and middle income


* All costs are calculated for moderate or higher degrees of hearing loss, i.e. hearing level greater than 35 dB in the better-hearing
ear. The costs are estimated in 2015 International dollars (a unit of currency defined by the World Bank and represented simply as
“$” in the table).
N.B. The analysis takes no account of certain aspects of hearing loss, the costs of which are not well documented in literature, such as the costs
of providing informal care, or pre-school learning and higher education for people with unaddressed hearing loss (201).
These estimates focus only on unaddressed hearing loss and do not take into account
the high costs posed by otitis media and its management. The costs attributed to
the medical and surgical management of these potentially preventable diseases are
high. In Australia, for example, treatment costs for cases of otitis media, excluding
complications and comorbidities, were 100–400 million Australian dollars in 2008
(211). In the Republic of Korea, a nationally representative study estimated treatment
costs of otitis media as 497.35 million US dollars in 2012 alone (212). In contrast
to the data provided above, these costs refer to management of this group of
conditions in certain countries. Nonetheless, their inclusion here is relevant since
these costs could be mitigated by preventive actions as outlined in Section 2.
Hearing loss has the potential for adverse effects at all stages of life; however, the
impacts described in this section can be mitigated if it is addressed in a timely and
appropriate manner, as highlighted in the upcoming sections.