On the interaction of disability and aging: Accelerated degradation models and their influence on projections of future care needs and costs for personal injury litigation.

Purpose: Accelerated degradation models are emerging as ways to characterize the interaction between disability and the functional decline of aging and to provide insights about the processes of aging with disability. Typically the models employ sophisticated mathematical treatments that are beyond the scope of many clinicians, lawyers, and others who might benefit from the information they contain. The purpose of this report is to characterize some rudimentary features of the models, in more readily understandable language, and illustrate how understanding of the underlying constructs can influence decisions regarding resource allocation and other projections of future care needs.

Methods: A literature review of longitudinal aging and disability studies was completed and simplified mathematical modeling undertaken, with hypothetical data, to illustrate various outcomes of the interaction of disability with the functional decline of aging. A specific example, drawn from personal injury litigation, i.e. projection of future care costs, was used to illustrate the practical applicability of this conceptual model.

Conclusion: Awareness of the accelerated functional decline brought about by the superimposition of age-related functional losses on pre-existing disability reveals a need to provide for aids and personnel supports at an earlier age than might be expected because of the multiplicative interaction and the inadequacy of functional reserves to compensate for the disability.