THE DISABLEMENT CONTINUUM
As explained in Chapter 3, Saad Nagi proposed the original disablement model in 1965 (Nagi, 1965), with the intent to characterize disease across a continuum of dysfunction, rather than limit it to a description of the disease process (see Fig. 3–1). Before the development of the World Health Organization (WHO) model, several other models were developed. Each was designed to improve on the Nagi model or address disablement from a different perspective.
One of the limitations of Nagi's model is that it did not recognize the impact of societal factors, such as the availability of elevators or handicap ramps, on normal function for disabled persons. The National Center for Medical Rehabilitation Research (NCMRR) took Nagi's model further and developed a disablement model that breaks disablement down into five components including societal limitations on activities of daily living (National Advisory Board for Medical Rehabilitation Research, 1993).
In addition to the Nagi and National Center for Medical Rehabilitation Research models are three other disablement models in the literature:
The revised National Center for Medical Rehabilitation Research model
The World Health Organization model
The Institute of Medicine (IOM) model
The first two models are evolutions of the Nagi model and were developed as understanding of disablement evolved. The third model developed to accommodate the needs of the field of rehabilitation engineering more effectively.
The National Center for Medical Rehabilitation Research Model
The National Center for Medical Rehabilitation Research model (National Advisory Board for Medical Rehabilitation Research, 1993) divides disablement into five distinct components and includes Nagi's original dimensions in addition to societal limitations (Appendix Fig. C–1) (Snyder et al., 2008). The advantage of this division is that it aids clinicians' understanding of what they are treating and facilitates a better therapy model to improve health across the entire spectrum.
Appendix Figure C–1
The Nagi model extended to the National Center for Medical Rehabilitation Research (NCMRR) model. (From Snyder, A. R., Parsons, J. T., Valovich McLeod, T. C., Bay, R. C., Michener, L. A., & Sauers, E. L. . Using disablement models and clinical outcomes assessment to enable evidence-based athletic training practice, part I: Disablement models. Journal of Athletic Training, 43, 428-436.)
Pathophysiology refers to damage at the cellular level. All disease or injury involves some type of damage or alteration in physiology at the cellular level. For example, a heart attack results in death of cardiac tissue, and high blood pressure causes damage to the blood vessels. Alternatively, a knee meniscal cartilage tear results in some amount of tissue tearing damage.
At this level, diagnosis requires some type of medical test to assess the damage. For a heart attack, this could be ...