ICIDH Model of Disability

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A global common language in the field of disability has long been wanted. For this purpose the International Classification of Impairments, Disabilities and Handicaps (ICIDH), was first published in 1980 by World Health Organization (WHO), as a manual of classification relating to the consequences of diseases. While the International Classification of Diseases (ICD) deals with diseases, the ICIDH deals with the consequences of diseases, i.e., impairment, disability and handicap. "Disablement" is sometimes used as an umbrella term covering all three dimensions.


ICIDH consists of two parts: a conceptual model and three classifications.

The first part is the theoretical explanation of the consequences of diseases. It proposes the concepts and definitions of impairment, disability and handicap and discusses the relation between these dimensions showing the conceptual model illustrated in Figure 1. This is based on a linear model implying progression from disease, impairment, disability to handicap.

Figure1: ICIDH Model (WHO 1980)

The impairment is characterized as an abnormality of structure or function of body or organ including mental function. The disability is characterized as a restriction of activities resulting from an impairment. And the handicap is the social level of the consequences of diseases characterized as the individual's disadvantage resulting from impairment or disability.

The second part of the ICIDH is three independent classifications of impairments (1009 items), disabilities (338 items) and handicaps (72 items).

Today ICIDH is available in 15 languages including Japanese and Chinese, and is used in a variety of fields such as medical, vocational, educational, and social rehabilitation, policy and administration, statistics, research, and education and training.

Revision of ICIDH

In paralled with the wider use of the ICIDH, criticisms and requests for revision have grown and led to the revision process. Since 1990 WHO has organized annual meetings. WHO Collaborating Centres for the ICIDH and the International Task Forces have been supporting the process. These centers are located in the Netherlands, France, North America, Sweden for Nordic Countries and Australia.

The New ICIDH (ICIDH-2) is to be adopted by WHO General Assembly in 1999. A global field test to refine the draft ICIDH-2 started in 1996. The field test consists of "alpha test" (June 96 - Dec 96), "beta test 1" (Jul 97 - Dec 97) and "beta test 2"(1998).

During the "alpha test" phase a set of draft proposals for ICIDH-2 was prepared by the coordination of WHO and discussed among those who had already been involved in the revision process. Now a new draft is coming by the first week of July 1997 to be tested in the "beta test 1" phase. In the "beta test" wider organizations and users of the ICIDH including potential users of the ICIDH-2 in different countries are expected to take part. The participants will be asked to evaluate the draft ICIDH-2 concerning the ease of use, applicability, relevance of main and sub categories and definitions, etc. The results of the "beta test 1" will be used to prepare a revised draft which will be discussed in a revision meeting in Tokyo in March 1998 (planned), and be tested in the "beta test 2". WHO is looking for a government or non-government agency in each country which is willing to work as a field test coordinating site. As all of the ICIDH Collaborating Centers are located in Western countries, participation and contribution from Eastern countries are expected to make the revision process and new ICIDH truly international.

Some Issues in the Revision

Although the draft ICIDH-2 is not available at this moment, early June 1997, the followings have been proposed and discussed so far. All of them will be tested in the beta test 1.


"International Classification of Impairments, Activities and Participation -- A Manual for Dimensions of Disablement and Health" is proposed. Current ICIDH is named "International Classification of Impairments, Disabilities, and Handicaps -- A manual of Classification relating to the Consequences of Diseases." Neutral terms were preferred and negative terms such as disability and handicap were avoided. "Consequences" was deleted as the term may imply causal or temporal relationship, which is yet unproven. "Diseases" was also deleted as other health conditions such as aging may relate to disablement.

Graphic Illustration of Conceptual Model

Figure 2 has been discussed in the alpha test. It emphasizes the role of contextual or environmental factors and bidirectional interaction among factors replacing the unidirectional relationship in figure 1.

Figure2: New ICIDH Model (proposed)

Definitions of Participation

"Participation is the nature and extent of a person's involvement in life situations in relationship to impairments, activities and contextual factors" is proposed as a first option. The second option is "in the context of a health experience, participation is a person's involvement in life situations. A restriction of participation is a reduction in the nature or extent of a person's involvement in life situation." The definition of handicap in 1980 version is "in the context of health experience, a handicap is a disadvantage for a given individual, resulting from an impairment or a disability, that limits or prevents the fulfillment of a role that is normal (depending on age, sex, and social and cultural factors) for that individual".

Definition and Classification of Context

Contextual factors usually interact with impairments, activities and participation. Especially they play an important role in determining the level of participation. These factors can largely be grouped into environmental or extrinsic factors on the one hand and personal or intrinsic factors on the other. However, so far the personal factors are not included in the proposed definition nor classification of Context.

Context is defined: "context includes the features, aspects, attributes of, or objects, structures, human-made organizations, service provision, and agencies in, the physical, social and attitudinal environment in which people live and conduct their lives." Proposed classification begins with products, facilitating objects and services usable by the person, and then moves to agencies that provide those goods and services, the social, economic and political institutions that create and maintain those agencies, the social norms, rules and attitudes that sustain the institutions and, finally, the physical world at large.

Other important points include:

1. Separation of the impairment dimension into function and structure,

2. Boundary problems between three classifications,

3. Boundary problems between ICD and Impairment Classification,

4. Level of detail in the classification,

5. Definition of impairment and activity,

6. Applicability in age groups such as children and the elderly,

7. Applicability in mental health.

New ICIDH and AP Decade

The first meeting to review the progress of the Asian and Pacific Decade of Disabled persons, 1993-2002 was convened by UN-ESCAP and held in Bangkok, Thailand from 26-30 June 1995. It was one of a series of review meetings which is planned to be held once in every two years during the Decade. About 200 participants representing GOs or NGOs from 28 countries in the region discussed the future targets as well as the progress in the past two "71 time bound targets" and many recommendations. ESCAP members, i.e., governments in the regions, and ESCAP headquarters are expected to follow the targets and recommendations. The ESCAP General Assembly in April 1996 officially adopted these targets and recommendations. Some targets and recommendations are related to the ICIDH. The followings are excerpts from the Report of the Meeting.

In "Information and Public Awareness":

Target 3.1: Establishment, by 1998, of a nation resource center with an accessible information and database on the disability situation, including demographic data on persons with disabilities, as well as social and economic dimensions, including employment status, educational level, housing and membership in registered organizations of people with disabilities.

Target 3.2: Initiate, by 1998, a national sample survey.

Recommendation 7:

The governments of the region may undertake steps to include questions on disability in the national population census as a long-term measure.

In "Prevention of Causes of Disability, Rehabilitation, Health and Social Development":

Recommendation 2:

Minimal levels of data shall be collected by all countries using standard terminology in accordance with the WHO International Classification of Impairment, Disability and Handicap.

In "Regional Cooperation":

Recommendation 1:

ESCAP, in close cooperation with concerned members of the Asia-Pacific Inter-organizational Task Force on Disability-related Concerns, may collaborate in:

Assisting governments in carrying out national sample survey by :

1. Providing technical expertise to facilitate disability-related data collection;

2. Providing training to trainers of census enumerators in the interpretation of definitions for data collection;

3. Disseminating the United Nations Statistic Handbook on Impairments, Disabilities and Handicaps, which will be published by the end of 1995.

The UN-ESCAP document mentioned above clearly indicates the usefulness and necessity of the ICIDH in collecting basic and reliable information on persons with disabilities. The ICIDH is also useful in other areas concerning disability. The conceptual model of the ICIDH has been used in rehabilitation interventions for many years. An individualized rehabilitation plan or service plan can be broken down into intervention plans in every dimension of the disablement. The assessment of the impairments leads to the treatment plan and the assessment of the disability (limitation of activities in ICIDH-2) will be used to identify the rehabilitation services needs, including needs for technical devices. And the Assessment of the nature and extent of participation in conjunction with the assessment of the contexts lead to the services plans, including residential resources, transportation, home help services, recreational services, incoming support services and physical adjustment of working environment. The evaluation of the nature and extent of participation can give the overall effectiveness of various interventions.

The ICIDH is also useful in developing a cohesive disability policy. I would like to explain this aspect by showing recent Japanese experiences in the field of mental health policy.

ICIDH and Japanese Mental Health Legislation

Last ten years in Japan, we experienced a successful policy expansion in mental health with the help of the conceptual framework of the ICIDH. The understanding and recognition of the different dimensions, i.e., disease, impairment, disability and handicap, were used to develop the policy to include rehabilitation services in late '80s and social welfare services in early '90s.

In 1986, the Advisory Council on Public Health recommended a new understanding to the Minister of Health and Welfare that people with mental disorder are not merely people with illness, but also with disability who experience difficulty, restriction or disadvantage in their social life.

This Council Recommendation resulted in the amendment of the Mental Hygiene Act the following year (1987) which renamed it to Mental Health Act and provided a new facilities for social and vocational rehabilitation.

In 1990s the Act was revised a few times and group home program was established. This program provides accommodation, meal, consultation, and other daily living assistance in a group home. It is neither treatment nor training but assistance and support.

Medical treatment response to disease or impairment, and rehabilitation or training to disability, and social support to (micro) environment. Our goal is to eliminate handicap. To achieve this, every possible approach should be used.

The revised ICIDH-2 which will be published by 1999 will play more important role in policy/legislation development by its well arranged conceptual framework reflecting the reality. It will be very useful in all Asian and Pacific countries.


UNESCAP. (1995). Report of the Meeting to Review the Progress of the AP Decade of Disabled Persons, 1993-2002. Bangkok.

WHO. (1997). Documents for Meeting for the Finalisation of the Beta Draft of the ICIDH-2 for Field Trials. Geneva.

WHO. (1980). International Classification of Impairments, Disabilities, and Handicaps. Geneva.

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