Opportunities to Improve Survey Measures of Late-Life Disability: Part II - Workshop Summary. Linking Measures of Assistive Technology and Disability

09/27/2006

Dr. Agree presented results from a project funded by the U.S. Department of Health and Human Services Office of the Assistant Secretary for Planning and Evaluation (ASPE) to develop and disseminate a set of questions on assistive technology use and the home environment for national surveys on health and aging.1 The project involved an extensive review of existing measurement approaches, consultation with stakeholders in policy and national surveys, discussions with technical advisory group members, cognitive testing at the National Center for Health Statistics and a pilot study conducted by Westat of 360 people ages 50 and older. Roughly equal numbers of people 50-64, 65-79 and 80+ were administered a 25 minute computer assisted telephone interview. The sample represented persons at all levels of ability and approximately 20 individuals living in assisted living settings were included. Evaluation of the pilot instrument involved both an in depth interviewer debriefing, and coding of 150 taped interviews for key interviewer and respondent behaviors indicative of potential problems. Based on analysis of the pilot results, an eight minute version consisting of several modules was recommended. Few behavior problems were reported for these items (on average less than 3%, except for probing which was approximately 7%, typical for this age group).

Dr. Agree presented results from the pilot and recommendations in four areas: the home environment, assistive device use, the use of global vs. specific items, and effectiveness of assistive technology.

Home Environment. Existing measures of barriers in the home environment are generally found on long home assessment forms used by trained professionals. They rely on subjective assessments of whether features are causing problems. Surveys on the other hand have generally asked few questions about the home environment. Based on the cognitive testing and pilot results the research team recommended a series of questions (approximately 2 minutes) to capture home features. The items distinguish the existence, acquisition, and use of these features. For example:

Assistive Device Use. With respect to assistive device use, there has been a proliferation of questions, using diverse terminology and varying levels of detail. Based on the pilot test, the research team recommended avoiding the terms special, assistive technology, and assistive devices, and instead using the phrase items that make your daily activities easy, safer, or so you can do them on your own; naming specific devices and providing definitions as needed; giving specific time frames for use (e.g., in the last 30 days); and not restricting questions to people who report having difficulty. For nonmobility devices, they recommend asking In the last 30 days have you used (name item). For mobility devices, they recommended a series of questions to capture frequency of use by task and location. For example:

The entire assistive device use section takes approximately two minutes to administer.

Global Versus Specific Questions. The research team also investigated whether items that asked simultaneously about the use of multiple devices identified assistive technology users with the same accuracy as the full module. The pilot found that these did not do so consistently across types of devices. A global item for mobility related technology (In the last 30 days have you used a cane, walker, wheelchair, or scooter?) had high sensitivity and specificity compared to individual items (0.94 and 0.99, respectively), but global items that referred to home features had much lower predictive power.

Effectiveness of Assistive Technology. Finally, with respect to measures of effectiveness, existing tools are generally clinical assessments about a specific piece of equipment; survey questions have most often evaluated satisfaction with or need for more assistive technology. The research team pilot tested two sets of effectiveness questions. The first set asked about difficulty with specific tasks using the specific devices or features named earlier in the interview but without assistance from another person. For example:

The residual difficulty module takes approximately 1½ minutes. These items had far fewer behavior problems than well established functional limitation items. The items also scale extremely well (Cronbach’s alpha=0.8).

A second set of effectiveness items asked individuals to report about specific outcomes related to their assistive technology. Three of the six items (which took approximately 30 seconds to administer) performed exceptionally well: Because you use these items how much safer do you feel when you do your daily activities? Because you use these items how much more control do you have over your daily activities? Because you use these items how much more often do you take part in activities that you enjoy? Preliminary structural equation models suggest that these three items scale well and correlate with the intensity of assistive technology use and the extent of functional limitations, but not with the amount of personal help.

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