Theories of "person-environment fit" propose that autonomy and security are opposite "poles of a dialectic" (see, for example, Parmalee and Lawton,1990). An environment that provides a high level of safety and security is likely to have a lower level of privacy, independence and choice. Pastalan (1970) has depicted the later stage of life as a series of adjustments to the "loss continuum," i.e. loss of job, income, health, spouse, etc. As each loss takes place, adjustments in the environment can be used to compensate. A common adjustment is residential relocation; however, relocation to a more safe and secure environment can result in a corresponding and undesirable loss of autonomy and control. One study found that about 50% of a large sample of older disabled people changed their living arrangements after onset of a disability (Newman, 1976). About 70% of those people moved either to an institution or relative's home, both of which are environments with a lower level of autonomy. Thus, removal of barriers to independence can contribute directly to the well being of older disabled people by reducing the need to relocate into a more restrictive environment.

Reliance on caregiver support is another form of compensation to the impact of the loss continuum. Yet, older people would rather have a more enabling physical environment than human intervention through supportive services (Holmes and Holmes, 1979). Moreover, the caregiver role is stressful and difficult. Caregivers, particularly if they are elderly spouses, also can benefit from enabling environments.

An extensive knowledge base exists about the nature of environmental barriers to accessibility and use of the environment (Steinfeld et al., 1979; Steinfeld, 1987), safety (Czaja et al., 1982; Carson et al., 1978; Watzke and Kemp, 1992) and security (Newman, 1973). There are also many publications identifying counter measures that can be used to eliminate these environmental barriers. Developing enabling environments through removal of barriers includes the utilization of architectural and interior design modifications, building technology, assistive devices, preventative maintenance and consumer education. Each has its role to play in developing the most appropriate strategy for an individual, setting and family.

Faletti (1984) suggests that recommendations for home modifications for younger disabled people may not always be appropriate for the older person, due to the prevalence of multiple disabilities and general frailty. In a pilot study, Pynoos and Ohta (in press) identified guidelines for home modifications that address hallucinations, aggression and other behaviors associated with dementia. More recent research (see articles in this issue by Olsen and Silverstein et al.) has also examined the needs of people with mental impairments.

The acceptance of any intervention by the consumer, family and caregivers is an important concern for implementation of interventions. Lifestyle, values, cost and level of disability play a role in the decision to accept an intervention. For example, some individuals do not like to cook. Their priorities for usable kitchens maybe very different than those of people who do. Some families may not accept environmental modifications or assistive devices as a substitute for caregiver support. The appearance of modifications and devices can affect acceptance. Resistance to the use of assistive devices is often based on the stigma associated with them. Faletti (1984) discovered that older people who have functional limitations may not perceive themselves to be disabled and, thus, less likely to perceive the need for interventions.

Home modifications include five basic services that directly support independent living (Steinfeld, 1981):

• security improvements such as improving locks, outdoor lighting, securing windows,
• fire safety improvements such as eliminating overloaded electrical circuits and installing smoke detectors,
• accident prevention measures, including repairing stairways, improved lighting, and repair of floor surfaces,
• accessibility and usability modifications including construction of entry ramps, installation of grab bars and adapting round door knobs with levers,
• construction related services such as emergency repairs, weatherization, maintenance and general rehabilitation.

The research literature, however, has focused almost exclusively on accident prevention, accessibility and usability, all health related concerns. Little is known about the relative importance of the other issues.

Pynoos et al, (1987) through a review of research and data from health service providers, observed that there is clearly a great need to focus programs for improving the level of home modifications for removing environmental barriers in existing housing of older people. They recommended that this effort should include the development of better assessment techniques. Data on individual differences, acceptance and priorities would be extremely valuable for improving the implementation of such services. This data could help improve programs such as occupational therapy services and "early warning" prevention surveys. It could help improve design of assistive technology, consumer products and building technology. In general, it could be extremely useful in developing new tools for helping older people and their families accommodate aging in place.

In summary, potential barriers to the accessibility, safety, security and usability of home environments for older people with disabilities are well known. As older people "age in place," these barriers present serious threats to independence. Many methods for eliminating barriers and creating enabling environments have been proposed. However, the needs of individuals and their specific home environments vary significantly and they differ from those of younger people with disabilities. There is a need for information on the types of barriers that "handicap" older disabled people and what specific interventions should be applied to remove them from the environments in which they live. Such information can be used to identify priorities for development of assistive devices, home modifications, innovative design concepts and service programs. It can help to prevent disability among the older population and increase autonomy.