Journal Issue: Children with Disabilities Volume 22 Number 1 Spring 2012
Diffusion Science and Disparity Creation
If technological innovation enhances efficacy, then factors that shape the diffusion of this new technology throughout a delivery system can be of crucial importance to health disparities. The diffusion of technical innovations has been studied since the late nineteenth century, but it became the focus of modern analysis after the publication in 1962 of the Diffusion of Innovations by Everett Rogers.60 Rogers defined diffusion as the process through which an innovation is communicated through certain channels over time among members of a social system, his point being that diffusion occurs through social systems.
The Social Determinants of Technology Diffusion
A variety of studies have demonstrated that diffusion generally occurs in an S-shaped curve over time, depicted as the solid line in figure 1. This shape represents a nonlinear pattern of adoption, reflecting different affinities for adoption in a population. Rogers categorized these different affinity groups as early adopters, majority adopters, and those who are ungenerously labeled laggards. These categories are illustrated in figure 1 as sections under the dotted line representing the distribution of adopters around the mean. A large body of work now documents the mechanisms that determine diffusion patterns. Not unexpectedly, much of this literature is focused on how best to optimize diffusion either to expand product market share or to alter patterns of practice.
For children with disabilities, the nature of the technical innovation and the practical delivery system are both crucial and highly interactive. The characteristics of innovations likely to move quickly through the S-curve include perceived utility, low cost (not only in dollars but also in ease of use), and good aesthetics. In addition, innovations that depend on a complex infrastructure for use may be more sensitive to the capacity of delivery systems for widespread adoption. For example, amniocentesis for prenatal diagnosis is highly dependent on a fairly sophisticated delivery system for its use. It should not be surprising, therefore, that in a socially stratified delivery system, social disparities in the use of amniocentesis are greater than those for other, less complex, prenatal screening technologies.61 Systems heavily dependent upon standardized payers, such as insurance plans, may prolong early adopter phases until the payer authorizes expenditures for mainstream adoption. In this manner, the innovation diffusion patterns are sensitive to the interaction of innovation and system characteristics.
The concern is that these potential interactions may create social differences in the diffusion patterns of highly efficacious innovations. For example, stratified delivery systems can delay adoption and have the effect of shifting the S-curve to the right along the time axis (figure 2A). In this manner, two populations may exhibit the same adoption pattern but with highly dissimilar time frames, which could create disparities in outcomes for any efficacious intervention for lengthy periods of time. Alternatively, socially disparate characteristics of the delivery system could arrest diffusion at some level of adoption along the S-curve (figure 2B). Adoption could slow, for example, if it required a certain level of base resources (say, for an intensive care unit) that may not be sufficiently available across the whole system serving a socially defined population.
Whenever efficacious interventions exist, differences in the diffusion of and access to these interventions are thus likely to play a major role in shaping disparities in health outcomes. General populations (including adults) show some signs of significant social disparities in access to assistive technologies.62 These disparities appear to be particularly large for expensive devices, such as powered wheelchairs.63 Significant variation in coverage policies among private insurance plans and public programs such as Medicaid have made it difficult, however, to fully gauge access disparities to important assistive technologies for children with disabilities.
Technology Design, Markets, and the Burden of Provision
While the inherent interaction between the characteristics of an innovation and the nature of the system dedicated to its functional delivery must be recognized, the forces shaping the design of the technology most relevant to children who are disabled should also be considered. Assistive technology has been generally considered, particularly by the health and human service community, as inherently compensatory or accommodative in nature. Basically, this technology is viewed as being directed at a selected population of disabled users who would benefit from the technology's ability to address a specific functional impairment. Under this approach, assistive technology often represents a specialized adaptation of broader technologies and is distinguished from technology in general on the basis of the rarity of a specific human need. In this setting, one would expect that the design and manufacture of this specialized assistive technology would be dominated by a set of relatively small, niche manufacturers, a phenomenon that traditionally has been very much the case.
An alternative approach perceives the design of technology for the disabled as part of the essential design of any technological innovation. Generally referred to as "universal design," this approach guides "the design of all products and environments to be usable by people of all ages and abilities to the greatest extent possible."64 This approach does not depend upon the delayed reconfiguration of a general technology to meet the specific requirements of the disabled. Rather, it attempts to design from the start innovations that are accessible to all.
Universal design responds to conceptual frameworks developed to create highly inclusive disability theory and law.65 It has proven most crucial in influencing the design of new digital technologies, particularly those mediating social communications through the Internet. The reasons have been twofold. First, designing computer software and hardware for universal use should be easier and less costly than designing many other general technologies for such use. Second, and more important, universal design may be most critical in settings of extremely rapid innovation. Adaptive designs, even when developed and implemented relatively rapidly, are not likely to keep up with a highly dynamic technology environment. This lag can lead to the chronic exclusion of disabled people from mainstream technology use. Although relatively little evidence is available regarding the impact of universal design on the activity and participation of children with disabilities, the importance of rapidly advancing digital technologies to the lives of all children, and particularly to disabled children, may underscore the importance of research in this area. In addition, the impact of universal design may prove particularly important in a setting of constrained public financing for health care services. The reduction or elimination of Medicaid support for the acquisition of assistive or adaptive technologies may only strengthen the utility of universal design strategies.
The potential utility of universal design is also closely related to the concern that small niche markets for adaptive technologies do not provide sufficient financial incentives to support the development of highly innovative products. Drugs or technologies for small markets, often termed "orphan" technologies, may be required to supplement broader, universal approaches.66 The record on the actual effectiveness and pricing of orphan medications and technologies has been mixed, however, and new strategies may be required to ensure the robust development of new interventions for relatively rare disorders. In addition, universal design may prove more practical for technologies used by large populations of disabled persons, such as the elderly—technologies that may or may not relate directly to the needs of much smaller groups, like disabled children.
An enhanced reliance on universal design, particularly given the persistence of social inequalities in access to computer and Internet-based technology (the well-known digital divide), will nevertheless require specific mechanisms that ensure universal access to the technology in question.67 This imperative highlights the potential need for specified, focused programs directed at affording access to disabled children and their families even if such programs are concerned with technology designed for and used by a general population. More broadly, rapid innovation in health-related technologies may blur distinctions between universal and orphan interventions. For example, advances in genetic testing technologies have generated hopes for individualized risk assessments and therapeutic plans, a new strategy of "personalized medicine."68 Such visions transcend traditional boundaries between universal and orphan approaches and underscore just how dynamic the interaction between technologic innovation and systems of dissemination can be.