Defining disability and rehabilitation

As a pre-requisite to understanding, it is essential that we are first able to define the construct of interest and its attributes or characteristics. This requirement is particularly a challenge in a multi-factor and multi-stakeholder field like “rehabilitation” alongside the discussion of health conditions such as those of musculoskeletal in nature which can at times be complex. Defining the construct of rehabilitation is a daunting task particularly given the complexity of rheumatologic and musculoskeletal disorders with rehabilitation as a process just as complex. However, rehabilitation is married to disability. Rehabilitation has many characteristics that if understood and captured appropriately and adequately, will benefit the discussion on how to mitigate the effects of disability recognizing that disability also has features that are multifactorial and multi-stakeholder. In understanding and defining disability, we should try to examine the concepts that encapsulate disability that will then inform proper rehabilitation process.

A prerequisite to defining rehabilitation is to first define “disability” (taken within the context of rehabilitation”). In 2001, the WHO (World Health Organization) developed the ICF (International Classification of Functioning, Disability and Health) to serve the purpose of being a reference framework in defining disability from an integrative biopsychosocial perspective. The ICF consists of various interacting components to include body functions, body structure, and activities and participation of an individual that depending on the nature of interaction of these components can lead to functioning (i.e. positive characteristics) or disability (i.e. negative characteristics) of the individual. These interactions can be influenced also positively or negatively depending upon the environment (e.g. environmental facilitator or environmental barrier) and personal factors ( Fig. 1 ). Hence, disability in ICF term is defined as an impairment of body functions and body structure and limited activity and restricted participation which may be associated with common and burdensome musculoskeletal conditions such as arthritis and low back pain. In essence the ICF can provide those areas (or domains) of functioning and disability pertinent to an individual or to a group of individuals.

International Classification of Functioning, Disability and Health (ICF) .

As the entire ICF taxonomy consists of more than 1400 ICF categories or “items”, empirically driven ICF Core Sets have been developed to capture only those categories that are relevant to a health condition(s) including musculoskeletal conditions, or setting(s). ICF Core Sets make the ICF practical and feasible to apply. For illustration purpose (see Fig. 2 ), a collection of common essential categories (i.e. brief version of a Core Set) present in at least 4 out of the six selected musculoskeletal ICF Core Sets: rheumatoid arthritis, low back pain, osteoarthritis, ankylosing spondylitis, osteoporosis, and chronic widespread (including fibromyalgia) . At a glance, the ICF categories relevant to musculoskeletal conditions cover a broad range of functioning domains across body functions (e.g. physical and emotional functions), body structures, and activities and participation (e.g. physical and social relationships and activities, community life participation). These categories were proven to be relevant when assessing and intervening on individuals with the abovementioned musculoskeletal health conditions. Hence, the list of categories ( Fig. 2 ) can be used as a potential pool of domains to field in clinical trials and intervention studies and also clinical care in musculoskeletal conditions. All ICF Core Sets for various health conditions and settings and can be freely downloaded at http://www.icfresearchbranch.org/icf-core-sets-projects-sp-1641024398 . Each ICF category is defined including its inclusions and exclusions in the ICF handbook .

ICF categories present in at least 4 out of 6 musculoskeletal conditions.

As evident in Fig. 2 , the ICF covers a broad array of constructs that can be examined given different musculoskeletal conditions. These constructs can serve as focal points upon which disability and rehabilitation can be assessed and reported in health care settings and by health care service providers. The same constructs or a selection thereof can be the targets of a rehabilitative intervention. Further applications of the listed constructs can also be the basis and foundation for sourcing out indicators or measures in conducting clinical trials or intervention studies in rehabilitation. Disabilities “indicators” based on Fig. 2 include a range of body functions such as physical (e.g. gait pattern), emotional, mental (e.g. energy and drive) and other forms of disabilities in areas that are important to individuals with musculoskeletal conditions like pain, sleep, and sexual functions. Under body structures, there are various musculoskeletal regions of the body that are relevant as well covering the upper extremity, lower extremity, and the trunk. Activities and participation covers a much broader aspect of life activities from carrying out body position, to walking, to basic and instrumental activities of daily living, to personal relationships, employment, and community life. All these constructs of disability can be influenced by contextual factors such as personal factors (innate characteristics of the individual) and environmental factors (support, physical device, services, etc.).

The ICF highlights the need to consider and assess those aspects of activities and participation of an individual in order to optimize functioning and minimize disability. This is one of the key differences between the ICF and the traditional biomedical model , the latter of which is primarily based on pathology and etiology of the disease. To illustrate this property of the ICF, Fig. 3 lists the ICF categories pertinent to the component of activities and participation that should be considered for when measuring the impact of and outcomes in musculoskeletal conditions and chronic widespread pain across a range of different rehabilitation-relevant health-care settings such as acute hospital, early post-acute rehabilitation facilities, and could also be used as outcome measures in clinical trials .

Outcomes in musculoskeletal conditions and chronic widespread Pain – ICF categories present in at least 2 out of 3 Core Sets or settings.

If we are to focus on activities and participation categories that have been found to be conceptually included in the outcome measures used in clinical trials in musculoskeletal conditions and chronic widespread pain ( Fig. 3 ), we can say that based on the ICF classification, most of the categories were related to mobility (e.g. changing basic body position, lifting and carrying objects, walking, etc.), self-care (washing oneself, dressing, eating, etc.), domestic life (e.g. preparing meals, caring for household objects), major life areas (e.g. employment), and community life (e.g. recreation, leisure). All these categories certainly give importance in considering the broader aspects of individual’s functioning that can be impacted by the disease, than the traditional and sole consideration for joint damage, tenderness, and pain.

Health conditions such as musculoskeletal disorders can affect any or all of the domains of functioning, which may result in disability in daily living. So, taking into account the different musculoskeletal-related categories or constructs that can depict the level of disability of an individual, it is evident that an ICF-based definition of disability captures the breadth of an individual’s experience of disability. These different domains can be amenable to rehabilitative interventions as part of the overall care for the individual.

Definition and elements of rehabilitation

Rehabilitation has been defined by the WHO as early as 1981 (pre-ICF era) to “include[s] all measures aimed at reducing the impact of disabling and handicapping conditions, and at enabling the disabled and handicapped to achieve social integration” . The same definition considers the influence of environment in facilitating social integration in addition to the role of the family and caregivers of the person with disability. Recently, the 2011 World Health Report defined rehabilitation as “a set of measures that assist individuals who experience, or are likely to experience, disability to achieve and maintain optimal functioning in interaction with their environment” . Looking into these definitions of rehabilitation, it is consistent with that of the definition of disability based on the ICF.

Definition and elements of rehabilitation

Rehabilitation has been defined by the WHO as early as 1981 (pre-ICF era) to “include[s] all measures aimed at reducing the impact of disabling and handicapping conditions, and at enabling the disabled and handicapped to achieve social integration” . The same definition considers the influence of environment in facilitating social integration in addition to the role of the family and caregivers of the person with disability. Recently, the 2011 World Health Report defined rehabilitation as “a set of measures that assist individuals who experience, or are likely to experience, disability to achieve and maintain optimal functioning in interaction with their environment” . Looking into these definitions of rehabilitation, it is consistent with that of the definition of disability based on the ICF.