International Classification of Functioning, Disability and Health

TLDR: The World Health Organization’s (WHO) International Classification of Functioning, Disability and Health (ICF) has been revised to recognize that the concept of disability resides largely in the sociocultural domain of the authors' lives rather than being an attribute of the individual.

Abstract: One of the take-home messages from the III Step Conference held in July of 2005 was a suggestion that physical therapists adopt the World Health Organization’s (WHO) International Classification of Functioning, Disability and Health (ICF)1 as a framework for discussion of health and disabling conditions. For those less familiar with the ICF model and other contemporary models of disability, I refer the reader to Jette’s article in the III Step Series published in Physical Therapy.2 The ICF succeeds the WHO’s International Classification of Impairments, Disabilities, and Handicaps,3 known as the ICIDH, which was first introduced in 1980. The model of disablement most familiar to physical therapists in the United States is Nagi’s model of disablement4 that served as a foundation for the development of the Guide to Physical Therapy Practice. Nagi’s model comprises four categories: pathology, impairment, functional limitations, and disability. The new ICF model includes three domains of human function: body functions and structures, activities, and participation. which generally are analogous to the levels from the Nagi model of impairment, functional limitations, and disability, respectively. The utility of disablement models lies in the definitions of the levels and their subdomains which, if widely adopted, would facilitate communication among health professionals around the world. Campbell5 discussed the application of such models in her presentation at III Step and illustrated the use of the Nagi model in her research as a framework for her well known textbook.6 Every model has its strengths and limitations, but the ICF has been designed to address major criticisms of other models of disability. First, the model has been revised to recognize that the concept of disability resides largely in the sociocultural domain of our lives rather than being an attribute of the individual. Second, the disabling process is conceptualized as dynamic and bidirectional process rather than a linear consequence of pathology, impairments, and functional limitations. This change incorporates the possibility for secondary impairments that result from a disabling condition. In addition, a strength of the new ICF is that it is grounded in health rather than disease. Notably, the foundational domain of the model is termed health conditions rather than active pathologies that characterized the Nagi model. That change to focus on health condition makes the model more appropriate for the study, consideration, and discussion of health promotion. I urge our readers to familiarize themselves with the ICF and begin to frame discussion of clinical cases, research and professional discourse using its terminology.