RESNA 27th International Annual Confence

Technology & Disability: Research, Design, Practice & Policy

June 18 to June 22, 2004
Orlando, Florida


J.W. Jutai1, M . J. Fuhrer2, M . J. Scherer3,
F . DeRuyter4, and L. Demers5
1Department of Physical Medicine & Rehabilitation, University of Western Ontario
2National Institute of Child Health and Human Development, National Institutes of Health
3Institute for Matching Person & Technology
4Division of Speech Pathology and Audiology,
Duke University Medical Center
5École de réadaptation, Université de Montréal


The Consortium for Assistive Technology Outcomes Research (CATOR) was established in 2001 with a 5-year grant from the National Institute on Disability and Rehabilitation Research (NIDRR). One of its principal objectives was to review existing approaches to assistive technology (AT) outcomes measurement and examine how well they have been conceptualized in order to: (a) clarify the definition of AT outcomes; (b) develop a consistent and standard terminology/taxonomy; and, (c) develop a framework for conceptually modeling AT outcomes. In this paper, we report on the significant progress CATOR has made in developing a conceptual foundation for researching AT outcomes.


assistive technology, model, outcome, taxonomy


Gitlin 1 proposed that the range of assistive technologies encompasses essentially five major forms of intervention: (1) assistive devices (applied to or directly manipulated by a person); (2) special equipment (attachments to the original structure of the physical environment); (3) structural alterations (changes to the original structure of a physical environment); (4) material adjustment (alterations to nonpermanent features of the physical environment); (5) environmentally-based behavioural modification (changes to a person's interaction with the physical environment). This paper uses the term ‘assistive technology device' (ATD) to refer to an assistive device or piece of special equipment, as described above.

ATD outcomes research is defined as the systematic study of the effects produced by ATDs in the lives of users and their environments. According to Fuhrer et al. 2 ,

Those changes may range from improvements in delimited aspects of users' motor, sensory, and cognitive functioning to enhancement of their social participation, vocational productivity, and subjective well-being. The cascade of outcomes may extend to individuals' environments as well and include, for example, a reduction in caregivers' assistance and decreased costs to insurers and social welfare agencies.


The CATOR approach to the conceptual modeling of outcomes provides an overarching framework that can be applied to virtually any form of ATD 2 . The framework has the following key features: (1) designed to be a template for causal models that are specific to given types of ATDs; (2) views ATD use as a developmental (time-dependent) process that has at least two distinguishable stages, the first being the procurement of a device, and the second comprising all subsequent episodes of device use and nonuse; (3) considers that a complete analysis of ATD outcomes includes both objective and subjective perspectives, from all significant stakeholders whose views might affect the value attributed to different outcomes; (4) incorporates applicable concepts and terminology from the International Classification of Functioning, Disability and Health (ICF; WHO 3 ); (5) e mphasiz es the role of ATD use rs' personal goals ; (6) assigns the highest priority to measuring outcomes that relate to individual users' needs and objectives in obtaining devices ; (7) identifies important roles for optimizing ATD outcomes that are played by both mediating events, and also moderating factors that may themselves be modified by interventions and those that may not; (8) proposes that the endpoints for modeling are either continu ed use of a device in the longer term or discontinuation of its use.

A key process for advancing ATD outcomes research is adoption of a systematic approach to describing outcomes and meaningfully classifying them. The basic categories and concepts within a taxonomy need to be measurable, and their boundaries clear and distinct, if the classification is to be useful for scientific investigation. ATD users and providers should be able to use the taxonomy in a service context, for jointly considering the goals of device provision. ATD providers should also be able to use it to identify which outcome domains are most appropriate for a particular device user, and for documenting and evaluating ATD products and services delivered to the user. Device developers should find it useful for formulating comprehensive design goals for a projected device. Researchers should be able to identify theoretical and practical issues for planning outcome studies and testing device-specific causal models of ATD outcomes. CATOR has under development a taxonomy with the features that are described above.

CATOR advocates for an approach to classifying outcomes that would promote consistency in how ATDs can be distinguished, based upon their intended impact on the user 4 . The approach is designed to accommodate to the widest possible variety of ATD applications, reflecting combinations of user population, ATD type, service, and context for use. In essence, the provisional taxonomy proposes three main domains, for outcomes associated with effectiveness (that is, functioning, as defined in the ICF), efficiency , and subjective well-being . The Effectiveness domain embraces the full range of ATD impact, as defined in the ICF. The ICF permits at least two distinct forms of analysis for the effectiveness of ATDs: (1) the impact upon domains of user functioning (ICF Functioning); (2) the impact upon external influences on functioning and disability (ICF Contextual Factors). The Efficiency domain describes the impact of an ATD on the resources that are used in producing its effects upon user function 2 . It includes all ATD outcomes that might be considered to be socially significant in the sense that they describe impact upon such factors as service utilization. Subjective well-being refers to the degree to which an ATD affects how users appraise and feel about their lives, considered in terms of particular domains or in total 2 . In the framework proposed by Schulz et al. 5 , d evice s atisfaction would be subsumed under Subjective Well-being insofar as it reflects the extent to which ATD outcomes are acceptable as assessed by the user. User satisfaction may be seen as evidence for successful implementation of an ATD intervention, but by itself cannot be regarded as evidence for ATD effectiveness 6 .

The CATOR approach argues that ATD outcome measurement should take a longer-term and broader view – that is, successful outcomes should be defined to include evidence that skills acquired through rehabilitation ( proximal outcomes) are importantly exploited in real life ( distal outcomes). Proximal outcome dimensions are those in which the device is designed (engineered) to make a significant impact. The taxonomy should also have some way of identifying that each device is expected to have an impact in one or more of a much smaller set of distal outcome dimensions, such as utilization, satisfaction, subjective well-being, and quality of life.

We suggest that ATD outcome measurement include assessment of factors that moderate and mediate the device-outcome relationship. ATD services can moderate this relationship insofar as they can determine what devices are made available to the user, to whom devices are made available, and the means by which the user can procure a device. ATD services can mediate the device-outcome relationship in at least two fundamental ways 7 . They can seek to improve the fit between a device and its user. They can also seek to improve the fit between a device and the environments in which it is to be used, and thereby enhance the potential for a user to access environments using with the device 8 .


Clearly, there is a need to improve how outcome dimensions are conceptualized so that they can be effectively operationalized and researched. In this paper, we have made some modest proposals. We look forward to feedback from our audience as we move forward in this critically important area.


This work was funded in part by grants from the National Institute on Disability and Rehabilitation Research (through the Consortium for Assistive Technology Outcomes Research, grant H133A010401), and the Ontario Ministry of Enterprise, Opportunity and Innovation (through the Ontario Rehabilitation Technology Consortium). The principal investigators in the Consortium on Assistive Technology Outcomes Research (CATOR ) are Frank DeRuyter (Project Director), Wendy Coster, Marcus Fuhrer, Jeffrey Jutai, and Marcia Scherer.


  1. Gitlin, L.N. (2002). Assistive technology in the home and community for older people: psychological and social considerations. In: M.J. Scherer (ed) Assistive technology: matching device and consumer for successful rehabilitation. Washington, DC: American Psychological Association; 109-122.
  2. Fuhrer, M.J., Jutai, J.W., Scherer, M.J., & DeRuyter, F. (2003, in press). A framework for the conceptual modeling of assistive technology outcomes. Disability and Rehabilitation.
  3. World Health Organization. International Classification of Functioning, Disability and H ealth . Geneva: World Health Organization, 2001 .
  4. Jutai, J.W., Fuhrer, M.J., Scherer, M.J., & DeRuyter, F. (2003). Toward a taxonomy of assistive technology device outcomes. Manuscript in preparation.
  5. Schulz, R., O'Brien, A., Czaja, S., Ory, M., Norris, R., Martire, L.M., Belle, S.H., Burgio, L., Gitlin, L., Coon, D., Burns, R., Gallagher-Thompson, D., & Stevens, A. (2002). Dementia caregiver intervention research: in search of clinical significance. Gerontologist, 42, 589-602.
  6. Rossi, P.H. (1997). Program outcomes: conceptual and measurement issues. In: E.J. Mullen & J.L. Magnabosco (Eds.), Outcome measurement in the human services: cross-cutting issues and methods. Washington, D.C.: National Association of Social Workers Press.
  7. Batavia, M., Batavia, A.I., & Friedman, R. (2001). Changing chairs: anticipating problems in prescribing wheelchairs. Disability & Rehabilitation, 23, 539-548.
  8. Scherer, M.J. (Ed.) (2002). Assistive technology: matching device and consumer for successful rehabilitation. Washington, D.C.: American Psychological Association.

Address correspondence to:

Jeffrey W. Jutai, Ph.D.,
Department of Physical Medicine & Rehabilitation,
University of Western Ontario,
Parkwood Hospital, 801 Commissioners Road East,
London, ON, Canada N6C 5J1
Tel: (519) 685-4292 ext. 42626;
Fax: (519) 685-4582;

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