6.1.3 The WHO definition
The WHO is one of the most important of the organisations that are continuously working on a general definition of disability: Since 1980 the International Classification of Impairments, Disabilities and Handicaps (ICIDH) has been the leading classification system regarding the process of understanding and defining disability. It was reviewed in the late 1990s and led to the setting up of the International Classification of Functioning, Disability and Health (ICF) in 2002.
In the understanding of the ICIDH, “impairment” refers to the physical situation of the person; “disability” means the restriction of activities due to the impairment; and “handicap” expresses the limitations in terms of fulfilling a social role. Impairment refers to the level of an organ as a functional or structural abnormality of the body; disability means the impact of the impairment on the performance of the individual; and a handicap is the overall consequence of the impairment and/or disability, as per the figure below:
As per these two examples, the ICIDH saw impairment as the key factor in causing disability and handicaps. The ICIDH was therefore linked to the medical or individual model of disability. An impairment must not necessarily result in a disability and a handicap, but an impairment could result directly in a handicap, without being considered a disability.
With the emergence of new disability models, the WHO subsequently reviewed its classification and published the ICF in 2002. This classification came up with three dimensions of human functioning and disability: the body, activities, and participation. Thus disability involves dysfunctionality at one or more levels: it is an umbrella term for impairment (meaning problems in body functions and structures), activity limitation and participation restriction (WHO, 2002, p. 10) (see figure).
Examples
| Health Condition | Impairment | Activity Limitation | Participation Restriction |
|---|---|---|---|
| Leprosy | Loss of feeling in the extremities | Difficulties in grasping objects | The stigma of leprosy leads to unemployment |
| A person who formally had a mental problem and was treated for a psychotic disorder | None | None | Denied employment because of employer prejudice |
By using the term “functioning”, less emphasis is put on the individual deficiencies of a person, and “a continuum of health status” (Bonnel, 2004, p. 30) is recognised. The classification stresses the environmental factors (including the physical environment, as well as attitudes, services and policies) which facilitate or restrict a person’s potential to participate in daily life. The ICF accepts neither the medical nor the social model as valid on its own. Disability means a complex system with elements occurring on the individual body level in combination with the structure of society. The ICF suggests a synthesis of the two models under the new name the biopsychosocial model (see WHO, 2002, p. 9). However, this model is not yet established, and other authors do not use it.
The ICF provides a planning tool for decision-makers: together with the new definition, the WHO has published a checklist for measuring a person’s level of functioning. This checklist not only gathers medical data, but also social data, and the questions concern health status, activity and participation.
- ICF - Levels of functioning (adapted from WHO, 2002, p. 9)
More information
World Health Organization (2002): Towards a Common Language for Functioning, Disability and Health. ICF, Geneva.
The Dictionary on Disability Terminology by the Disabled People’s Organisation, Singapore might also be helpful.
