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As printed in Hearing Health, volume 20:2,
Summer 2004
By Christian Garms and Andrew Smith
Recent figures illuminate what is rapidly becoming
a critical situation: over 166 million people in the
developing world face a severe lack of intervention
services for hearing loss. According to the World Health
Organization (WHO), this crisis results from a substantial
increase in “disabling hearing impairment”
over the last 15 years.
Based on 2001 estimates, the most recent available,
250 million people have disabling hearing impairment,
which is defined as hearing loss that measures in the
moderate through profound ranges in the better ear.
This represents approximately 4.2 percent of the world’s
population, a much higher prevalence than was previously
thought. Two-thirds live in developing countries and
75 percent experienced adult-onset loss while the rest
have had hearing impairment since childhood. Additionally,
340 million people have mild hearing loss.
The increase in hearing impairment over the last decade
and a half is most likely due to a combination of factors.
Among them is improved diagnosis, earlier detection,
longer survival rates among elderly people, who have
the highest prevalence of deafness and hearing impairment,
and increased incidence, probably due to exposure to
excessive noise and ear-toxic drugs.
The Global Burden of Hearing
Loss
Since 2001, WHO has included adult-onset hearing loss
as a contributor to the “global burden of disease”
(GBD) in its annual World Health Report. Contributors
to the GBD are ranked according to the percentage of
the worldwide total of disability-adjusted life years
(DALYs) attributed to each one. DALYs are a measure
of the years of healthy life lost due to premature mortality
and the years lived with disability, thus taking into
account the burden of chronic conditions rather than
focusing only on mortality.
Adult-onset hearing loss ranked 15th in the year 2002,
coming after, in descending order, birth-related conditions,
respiratory infections, HIV/AIDS, depression, diarrhea,
heart disease, strokes, malaria, road accidents, tuberculosis,
maternal conditions, chronic lung disease, congenital
anomalies and measles. However, if one excludes mortality
and focuses on disability alone, adult-onset hearing
loss ranks second only to depressive disorders.
Assessment of the contribution that deafness and hearing
loss make to the GBD (or lack of health) is a public
health approach to the problem. But we must not forget
that these conditions have profound effects on individuals.
In particular, they damage the development of speech,
language and cognitive skills in children, especially
if hearing impairment precedes language development,
and they slow progress in school. They lead to difficulties
in obtaining, keeping and performing effectively in
an occupation. For people of all ages, they produce
significant social isolation and stigmatization.
All these difficulties are magnified in developing countries
where there are generally very few services or trained
staff and little awareness about how to deal with disabilities.
Deafness and hearing impairment also have huge economic
effects on communities and countries but in most, these
remain to be quantified.
As with most health issues, the impact of untreated
hearing loss is too large and too complex for any one
stakeholder to fully achieve intervention and prevention.
The only way to succeed will be through a pooling of
resources and an equal collaboration among all members
of society, one emulating the “grand alliance”
as envisaged by the late Sir John Wilson, the blind
and deaf founder of Sight-Savers International. Within
the last three years, creation of such a potentially
powerful force has begun (see chart on right).
Forging Creative Partnerships
In 2001, WHO published “Guidelines on Hearing
Aids and Services for Developing Countries” (a
new edition will be published this year) and simultaneously
called on the private sector to provide affordable hearing
aids in the developing world. The guidelines describe
basic requirements for service delivery, fitting, follow-up
and repair. They also include a section on training
and establishing pilot projects and their evaluation.
While specifically targeting children and infants, the
guidelines cover teenagers and adults as well. Since
the lack of trained personnel and infrastructure, along
with affordability, are the major constraints on provision
of services in developing countries, much of the text
is devoted to human resource development and service
provision.
WHO proposed that the only way to address the complex
issues involved in providing sufficient numbers of hearing
aids and services in the developing world was to encourage
public/private partnerships between national governments
of developing countries and hearing aid manufacturers.
It was not until 2003 that key stakeholders concerned
with this problem came together at a workshop jointly
hosted by WHO and Christian Blind Mission at WHO headquarters
in Geneva, Switzerland. Participants came from 18 developing
and developed countries and represented governments,
non-governmental organizations (NGOs), commercial and
not-for-profit manufacturers, organizations of users
of hearing technology and hearing healthcare experts.
They agreed to form World-Wide Hearing Care for Developing
Countries (WWHearing), an independent, collaborative
organization initially coordinated by WHO. Its mission
is to promote better hearing through the provision of
hearing aids and intervention services in developing
countries and underserved communities within the framework
laid out in WHO’s guidelines.
The Task Ahead
Most of the world’s millions with disabling hearing
loss could benefit from hearing aids yet current annual
production of the devices is less than one-eighth of
the global need. The shortage is evident but less so
in developed countries where one-third of the hearing
aids required to fit all the people who need them are
available. In developing countries, the gap between
the supply of hearing aids and the need for them is
gargantuan.
Up to 30 million hearing aids would be needed annually,
together with services and staff to fit them, in order
to equip everyone requiring a hearing aid. Obviously,
there is a huge opportunity for manufacturers to expand
their markets and supply affordable and appropriate
hearing aids throughout the world.
Providing the instruments and requisite related services
on a large scale for developing countries and targeting
people who cannot afford them, often a majority, is
an example of using a public health approach to address
the problem. Such an intervention worldwide is probably
the most effective and economical way of making a major
reduction in the impact of this disability.
To successfully reach this goal, WWHearing seeks to
gather information on provision/need in developing countries,
encourage appropriate, affordable hearing aids and services,
stimulate public-private partnerships within national
efforts and promote projects for fitting, follow-up,
repair and training. Operating procedures and guidelines
for pilot projects of public-private partnerships are
in place and agencies in developing countries in different
WHO regions soon will be invited to launch pilot projects.
Objectives of the projects will be to:
- focus on adults with hearing loss between 41 and
80 dB in the better hearing ear and children with
loss between 31 and 80 dB
- increase provision of hearing aids and services
in underserved areas through local partnerships
- develop simple methods of identifying candidates
and measuring satisfaction
- show a positive effect of provision of
hearing aids using measures of satisfaction, social
impact and cost-effectiveness
- implement WHO guidelines within the model of service
delivery existing in the country
- develop criteria for measuring success of the intervention
Once these objectives are tested and refined in the
pilot projects, they will set the stage for all partners
in WWHearing to contribute toward achieving its goals.
They are best stated as eliminating avoidable deafness
and hearing loss in the future and providing affordable
and appropriate hearing aids and services in developing
countries at levels needed to successfully manage disabling
hearing loss.
We are confident that through this approach, the global
consequences of a major human disability can be ameliorated.
Christian Garms is executive director
of Christoffel-Blindenmission (Christian Blind Mission)
in Bensheim, Germany. He serves as chairman of the executive
committee of WWHearing.
Dr. Andrew Smith is the medical officer on
the WHO Team for Prevention of Blindness and Deafness
who is responsible for prevention activities for deafness
and hearing impairment. He is secretary of the WWHearing
executive committee.
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