Overview and Description
The term “Disability” has different connotations, depending on context. While the social context focuses on issues like prejudice, the medical context utilizes a diagnostic- therapeutic paradigm.1 The US Department of justice takes a legal approach to define disability under the Americans with Disabilities Act 2 , as does the Social Security Administration. 3 The rehabilitationapproach to disability integrates many concepts by using the World Health Organization International Classification of Functioning, Disability and Health (ICF) model.4 Some of these perspectives are presented in Table I. In order to understand the diverse perspectives on disability, it is useful to examine the conceptual models that have been formulated over time by stakeholder perspectives.
These conceptual models can be used not only to define disability, but also to understand the impact of the disability and context-specific factors on function. The models have applications for quantitative and qualitative assessment of disability and functioning, to inform needs and resources, monitor costs, direct social policy, and maximize awareness and acceptance globally.
Conceptual Models of Disability
While there are many models of disability, two categories stand at the ends of a spectrum – the “individual” or “medical” model where disability is seen as an attribute of an individual health condition, and the “social” model, where disability is a product of environment 5. A third category includes models in which disability is the result of the individual-environment interaction.2,6 Over the past few decades, newer models have evolved, that often incorporate the biopsychosocial model with other models and theories.
A) Medical Models of Disability
Medical models of disability equate pathology with inherent disability. For example, a person with hearing loss is considered disabled, just as a person with cancer is considered disabled. In these models, the disability is viewed as a defect that the field of medicine and healthcare professionals must fix. This implies that disabilities and disablement can be “cured” by medicine. A solely medical model of disability consequently leads to any individual with pathology, however severe it may be, qualifying for social aid and accommodations regardless of level of function. This resulted in the stigmatization, impoverishment, and institutionalization of many individuals with pathologies.6 Examples include the Nagi Model.
B) Social Models of Disability
Social models of disability frame disability in an environmental context. For example, a person with hearing loss is not disabled by the hearing loss itself, but by the environment not providing the appropriate resources for that person. This type of model was pioneered mostly by individuals who had been labeled as disabled by the medical models of disability. Through their self-advocacy, social models were conceived in order to defend autonomy and personal freedoms despite level of functioning.6
Mike Oliver, a pioneer of the social model in the 1980s, based the model on his belief that individual limitations is not the cause of the problem. Rather, it is society’s failure to provide appropriate services and adequately ensure that the needs of disabled people are taken into account in societal organization. 7
C) Biopsychosocial Models of Disability
As it became clear that disability was not a strictly medical concept nor a strictly social concept, there was a movement toward combining the concepts into a biopsychosocial models, developed initially by George Engel in the 1970s. 8 In 1980, utilizing these concepts, the World Health Organization (WHO) released the International Classification of Impairments, Disabilities, and Handicaps (ICIDH) that classified disability into three domains: impairment, disability, and handicap. Impairments were defined as abnormalities of body structure, appearance, and/or organ system and function. Disabilities were defined as the consequences of impairments in terms of functional performance and activity of the individual. Handicaps were defined as the disadvantages experienced by the individual as a result of impairments and disabilities.9
The ICIDH was revised several times, with the latest iteration being the International Classification of Functioning, Disability, and Health (ICF), defined in 2002. The ICF examines the interaction of health conditions and contextual factors to define the spectrum of functioning and disability at the organ system, individual and social levels. In this model, the term “functioning” includes body structure and functions at the organ system level, activities at the individual level, and participation at the social level. The term “disability” correspondingly includes impairment, activity limitation, and participation restriction. Contextual factors include external environmental factors and internal personal factors. The ICF puts emphasis on health and functioning rather than disability, and is formulated to complement the International Statistical Classification of Diseases and Health Related Problems (ICD-10).10
D) Other models of disability
Many models of disability have been applied practically in the context of specific conditions. Behavior models including the Theory of Planned Behavior (TPB) [and Social Cognitive Theory (SCT) were combined with the WHO ICF to study activity limitations and ambulation in a community-based cohort of community with and without chronic pain in the UK.11
Models that approach disability from a first-person perspective have been described in literature as phenomenological models. The first-person experiences have been categorized as pre-reflective, attuned and reflective.12
Applications of ICF
A) The common language of rehabilitation
The ICF offers a common language at multiple levels, including the individual level, the institutional level, and the social level. Multiple stakeholder involvement at each level is facilitated, permitting comprehensive problem identification and solving relevant to the context. Applications of the ICF include policy, economic, research and intervention studies.
The ICF is not without limitations. Some recommendations for improvement include distinguishing between elements of activity and elements of participation, adding quality of life concepts, and expanding upon contextual and personal factors.13
B) Defining Rehabilitation Strategy
The ICF has been used to define Rehabilitation as a “health strategy “that “applies and integrates approaches” rooted in concepts of functioning , contextual factors, capacity, performance, person-provider partnership, and self- perception, health condition course through continuums of care and across sectors with the goal of optimal functioning.14
C) Developing clinical tools
The World Health Organization Disability Assessment Schedule 2.0 (WHODAS-2) 15 was created in 1998 as WHODAS II in line with the ICF conceptual model and to be used in assessing the disability based on this model.
There are 36 items (self-administered and covering the past 30 days) on functioning and disability covering seven domains under WHODAS-2, which are the following (and explicit):
- Understanding and Communicating (6 items)
- Getting around (5 items)
- Self-care (4 items)
- Getting along with others (5 items)
- Life activities: Household (4 items)
- Life activities: Work/School (4 items)
- Participation in society (8 items)
For each item, the response is scored from 1 (No difficulty), 2 (Mild difficulty), 3 (Moderate difficulty), 4 (Severe difficulty) to 5 (extreme difficulty or cannot do), with scores for each domain based on item responses, with room for missing items up to 30% for each domain. A final score is then computed that fits into a range from 0 to 100 with higher score as evidence of higher disability.
Within each domain classification, health conditions are diseases, illnesses, or other health conditions, injuries, mental or emotional problems, problems with alcohol, and problems with drugs. Having difficulty with an activity means increased effort, discomfort or pain, slowness, and changes in the ways such activities are performed.
The “Rehabilitation Problem-Solving Form,” was developed as a visual representation of aspects of pathology as well as the relationships between disabilities and underlying factor, for interdisciplinary team meetings to discuss interventions and their goals16
Conceptual models of disability lie on a spectrum between social and medical perspectives. The biopsychosocial models combine features of both, and form the basis of the WHO ICF, that serves as the common language of rehabilitation and has been used to define rehabilitation strategy. It is vital for all stakeholders in rehabilitation to have a working knowledge of these models in order to appreciate the varying viewpoints and coordinate optimal care and resources for addressing disability.
- The Stanford Encyclopedia of Philosophy (Summer 2016 Edition), Edward N. Zalta (ed.), URL = <https://plato.stanford.edu/archives/sum2016/entries/disability/>.
- https://www.ada.gov/cguide.htm, Accessed Dec 12th 2020
- Part I – General Information (ssa.gov), retrieved from https://www.ssa.gov/disability/professionals/bluebook/general-info.htm, Accessed Mar 21st 2020
- International Classification of Functioning, Disability and Health (ICF), retrieved from https://www.who.int/classifications/icf/en/, Accessed Mar 21st 2020
- Deborah Marks (1997) Models of disability, Disability and Rehabilitation, 19:3,85-91
- Masala C, Petretto DR. Models of disability. In: JH Stone, M Blouin, eds. International Encyclopedia of Rehabilitation. 2010.
- Oliver, Mike. The Individual and Social Models of Disability. 1990. (Paper presented at the Joint Workshop of the Living Options Group and the Research Unit of the Royal College of Physicians on People With Established Locomotor Disabilities in Hospitals). http://disability-studies.leeds.ac.uk/files/library/Oliver-in-soc-dis.pdf.
- Engel GL: The need for a new medical model: a challenge for biomedicine. Science 1977;196:129-136.
- World Health Organization. 1980. International Classification of Impairments, Disabilities, and Handicaps: a manual of classification relating to the consequences of disease. Geneva:World Health Organization;1980. Published in accordance with resolution WHA 29.35 of the 29th World Health Assembly, May 1976.
- Towards a Common Language for Functioning, Disability, and Health. Geneva: World Health Organization; 2002.
- Dixon D, Marie Johnston M, Elliott , Hannaford P, Testing integrated behavioural and biomedical models of activity and activity limitations in a population-based sample, , Disability & Rehabilitation, 2012; 34(14): 1157–1166
- Martiny KM, How to develop a phenomenological model of disability, Med Health Care and Philos (2015) 18:553–565
- Field MJ, Jette AM, Martin L.Workshop on Disability in America: A New Look , Summary and Background Papers. Washington, DC:National Academies Press; 2006.
- Meyer T, Gutenbrunner C, Bickenbach J, Cieza A, Melvin J, Stucki G, Towards a conceptual description of rehabilitation as a health strategy, J Rehabil Med. 2011 Sep;43(9):765-9. doi: 10.2340/16501977-0865.
- World Health Organization Disability Schedule 2.0 (WHODAS-2) 2010 http://www.who.int/classifications/icf/WHODAS2.0_36itemsSELF.pdf?ua=1. Accessed April 24, 2014.
- Steiner W, et. al. Use of the ICF model as a clinical problem-solving tool in physical therapy and rehabilitation medicine. Phys Ther. 2002;82:1098-1107.
Original Version of the Topic
Alycia Reppel, MD, Segun Dawodu, MD. Conceptual Models of Disability. Published 9/20/2014
Prateek Grover MD PhD MHA
Nothing to disclose