5.1.3 WHO classification of impairments, disabilities, and handicaps

WHO Classification of Impairments, Disabilities, and Handicaps

A model of illness effects known as the World Health Organisation (WHO) International Classification of Impairments, Disability, and Handicaps (ICIDH) model was developed in the 1970s and later released in 1980 as a tool for the classification of the consequences of disease and of their implications for the lives of individuals. The classification system describes the effects of impairments, disabilities, and handicaps on individuals. This system, known as the International Classification of Functioning, Disability and Health (ICF), is designed to provide a comprehensive and standardized framework for describing and measuring health and disability at both the individual and population levels.

The ICF classifies impairments, disabilities, and handicaps according to two main components: the body functions and structures affected, and the activities and participation in which the individual is limited. This approach helps to identify and address the barriers that individuals with disabilities face, and promotes a focus on enabling them to participate in all aspects of life to the fullest extent possible.

This classification system is intended to be used in various settings such as in healthcare, rehabilitation, education and social services, and it aims to improve the provision of appropriate services, support and policy development to address the challenges faced by people with impairments, disabilities and handicaps.

The goal was to first clarify terminology, and then to create a model that went beyond a standard medical model with a sequence from aetiology to pathology to presentation. The medical model at the time was felt to be insufficient when applied to conditions that cannot be prevented or treated. This ICIDH model is more psychosocially orientated. As a result, the model offers a chain of consequences from impairment to disability to handicap, or from impairment to handicap directly.

According to the ICIDH model, disability is caused by impairment, which is caused by disease or disorder. Disability or impairment causes handicap.

Impairment:

Impairment is defined as a loss or abnormality of structure or function that operates at a level lower than that of the entire individual, frequently at the level of the organ.

Disability:

Disability is defined as a restriction or lack of capacity to undertake tasks at the individual level. Any restriction or lack of capacity to do an activity in the way or range regarded as typical for a human being is termed a disability.

Handicap:

Handicap refers to disadvantages and role constraints at the personal level in a social environment. A handicap is a disadvantage for a specific individual caused by an impairment or disability that restricts or prohibits that individual from fulfilling a normal function (depending on age, gender, and social/cultural variables). A handicap can emerge from impairment without the intervention of a disability state (eg. disfigurement). On the other hand, someone with a severe impairment may be able to live a somewhat normal life without being hampered.

References:

(1) Johnston, M. and Pollard, B. (2001). Consequences of disease: testing the WHO International Classification of Impairments, Disabilities and Handicaps (ICIDH) model. Social Science & Medicine, 53(10), pp.1261–1273. doi:10.1016/s0277-9536(00)00384-1.

(2) Kaplan, G. (2005). International Classification of Impairments, Disabilities and Handicaps – an overview – Biomedicine. [online] ScienceDirect. Available at: https://www.sciencedirect.com/science/article/pii/B012369398500267X.