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The Levels of Disability According to the WHO

The WHO (World Health Organization) published the “ICIDH” (International Classification of Impairments, Disabilities and Handicaps) for the first time in 1980. While the English-language term “disability” can be understood as a comprehensive generic term, the ICIDH distinguishes three levels or dimensions of disability and gives them different names. In German, too, attempts have been made to introduce different terms, although the translation lacks the conciseness of the English terms for linguistic reasons [1].

The ICIDH has been thoroughly revised and is now available as ICF (International Classification of Functioning). An essential difference of this new edition is that new terms were coined for disability and handicap. On the one hand, this is to introduce more comprehensive terms, on the other hand, the view should be directed from the disability to the (despite disability) existing abilities. It remains to be seen how these terms will fit into the overall classification. Here, for the sake of simplicity, the previous terms are still used, the new terms are placed next to them as a comment.

By the ICF, functioning and disability is understood as dynamic interaction between health conditions and contextual factors, both personal and environmental (Figure 1), which shows the interactions between the components. This interaction is also promoted as “bio- psycho-social model” representing a compromise between medical and social models where disability is the umbrella term for impairments, activity limitations and participation restrictions. Due to the definition of disability In the UN Convention on the Rights of Persons with Disabilities (CRPD), which says that disability results from interaction between persons with impairments and attitudinal and environmental barriers, disability is not an attribute of the person. Thus, progress on improving social participation can be made by removing or reducing the barriers which hinder persons with disabilities on their full participation in society.

The integrative bio-psycho-social model of functioning, disability and health.

Figure 1: The integrative bio-psycho-social model of functioning, disability and health [3, 4].

Impairment – (Health Damage)

This addresses the level of disruption of biological and/or psychological structure and function. Damage is understood to be “any loss or deviation from norm in psychological, physiological or anatomical structure or function”.

Disability – (Ability Disorder)

This is the level of impairment of the affected person's ability to perform purposeful actions.

Ability disorder is “any restriction or lack – resulting from an impairment – of the ability to perform an activity in the manner or within the range considered normal for a human being.”

The ICF replaces the term disability by activities, i.e. also by the restriction of activities.

Handicap – (Social Disadvantage)

This is the level of disturbance of the social position or role of the person concerned and his or her ability to participate in social life.

The ICIDH defines social impairment as “a disadvantage for a given individual, resulting from an impairment or a disability, that limits or prevents the fulfilment of a role that is normal – depending on age, sex, and social and culture factors – for that individual.”

Instead of the term handicap, the ICF uses the term participation, i.e. also exclusion from social participation.


“Social impairment (handicap) is, therefore, not a simple consequence of a physical or psychological damage and the resulting functional limitation, but is the result of the interaction between a disabled person's desire for inclusion and recognition and the attitudes and behavior of his/her environment. It is only through experiences of rejection, distancing, disregard and social exclusion that the whole experience of being disabled arises for the disabled person, namely, also as an experience of being disabled in one's own development and inclusion in society.” [2]

For clarification, the three levels mentioned above are again summarized graphically here. As an underlying level (cause of impairment), disease or injury can be included in the scheme (Figure 2).

Thus, the effect of “disability” depends on many factors. The same impairment or disability can thus lead to completely different handicaps (social disadvantages). Accordingly, the WHO formulates: “The situation people find themselves in may determine to what degree a disability is handicapping for them”.

This is where both rehabilitation technology and society in general should and must start. If the medical means available to us do not succeed in curing the impairment, the disability can be overcome through targeted personal and technical assistance and the handicap can be eliminated or reduced through acceptance in society.

The levels of disability and the underlying cause.

Figure 2: The levels of disability and the underlying cause [5].


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Use the following information to cite this book.

  • Author: Dr. Wolfgang L. Zagler
  • Title: Rehabilitationstechnik
  • Date: March 1, 2008
  • Location: Vienna, Austria
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List of Abbreviations

International Classification of Impairments, Disabilities and Handicaps
International Classification of Functioning
World Health Organization

List of Figures

  • Figure 1: The integrative bio-psycho-social model of functioning, disability and health [3, 4].

  • Figure 2: The levels of disability and the underlying cause [5].

List of Sources