Goal & Objectives: Our goal in developing the Changing Needs and Life Circumstances interview protocol was to design a survey instrument that would systematically measure (1) variations in the "natural course" of aging with physical disability and (2) identify the consequences of variations in timing, severity and socio-demographic characteristics for a broad range of quality of life indicators. These include: productivity, physical health, psychological well-being, social participation and need for, and utilization of, health-related services. The specific objective was to construct an instrument that would measure change over time and be: (1) one part quasi-epidemiological assessment of health and functional status, including the onset of secondary conditions; (2) one part needs assessment; and (3) one part identification of risk and resiliency factors associated with quality of life outcomes.

Conceptual Framework: Development of the instrument was guided by three theoretical perspectives: (1) the life course perspective on aging and disability, from the social sciences, which emphasizes the temporal structure of disability; (2) the biopsychosocial model of health from rehabilitation; and (3) the independent-living perspective, from disability studies, which emphasizes environmental factors.

Disabling Conditions: Five disabling conditions were selected for inclusion in the survey: cerebral palsy, post-polio, spinal cord injury, rheumatoid arthritis and stroke. These conditions were selected for both theoretical and practical reasons. On a theoretical level, they represent important variations in the average age of onset when disability occurs, ranging from birth and childhood with C.P. and Polio, to young-adulthood with SCI and R.A., and mid- to later life with both R.A. and Stroke. On a practical level, selection of these impairment groups was guided by the clinical strengths of Rancho Los Amigos Medical Center and our access to study populations.

Development: Constructing the Aging with Disability survey took two full years, working closely with our 12-member Consumer-Oriented Research Advisory Committee (CORAC), and involved the systematic evaluation of over 150 scales and instruments from the fields of rehabilitation and gerontology. Our original intent was to draw primarily on existing measures rather than create an entirely new instrument. Achieving this objective proved more difficult than anticipated, however, because of the lack of cross-disability research, in general, and, specifically, studies of change in function over the life course. Nevertheless, many of the questions in our protocol have been borrowed, either directly or with modification, from other studies. To document this, and for comparison purposes, the source of each borrowed item/scale is indicated in italics throughout the protocol.

Type of Data: Data generated from the survey consist of objective and subjective self-reports of both current status and prior condition, measured retrospectively for an earlier period in the disability trajectory. The specific reference points used for over-time comparisons vary by impairment group and, within group, by an individual's personal experience of disability. For example, the reference point for polio respondents is either the period of "physical best" (defined as time of maximum recovery when strength and endurance were the greatest) or, if no physical best, "five years ago". For R.A., because of the fluctuating nature of this condition, the options are more numerous and include: the most recent period of "remission" (defined as the virtual absence of arthritis-related symptoms of pain and swelling), the most recent "good period" (defined as period of relative stability with mild disease active), or the most recent "bad period" (defined as period of rapid disease activity); or, if none of these apply, "five years ago." Reference points for SCI are similar to those used for polio.

Contents: Version 1 of the interview protocol is organized into six major content areas: Part I, History of Disability; Part II, Demographic Characteristics; Part III, Physical Health Status and Services; Part IV, Function, Technology and Accessibility; Part V, Social Issues;, and Part VI, Psychology Well-Being and Lifestyle Practices (see the Table of Contents on pages i - ii of the protocol for a detailed listing of the sections and sub-sections within each part). With the exception of Part I, which is customized for each impairment group (see color coding of pages) to reflect differences in the temporal structures or trajectories of these three disabling conditions, the overall content of the interview (Parts II - VI) is the same for all respondents. However, within each part, we utilize an extensive branching system to capture variations in the life circumstances of respondents both within and between impairment groups. As a result of this branching, not all questions in each part or section are asked of all respondents.

Administration: With few exceptions, all surveys are conducted in the respondent's home or residence and administered by one of three trained research assistants, the project coordinator or principal investigator. To accommodate the cross-ethnic comparisons in our overall research design, two of the five data collectors are bilingual in English and Spanish.

Sampling Design & Subject Recruitment: All participants are randomly selected from either a county hospital-based population (Rancho Los Amigos Medical Center) or a community-based subject pool, using a 2x2x2 sampling design. The stratifying factors in this design consist of: gender or race/ethnicity (Hispanic vs. Non-Hispanic), gender for polio and ethnicity for rheumatoid arthritis; age of initial onset or duration of disability (age for polio duration for R.A.); and chronological age at time of entry into the subject pool (all groups). Because of inherent differences in the epidemiological characteristics of each disabling condition (e.g., the sex ratio for rheumatoid arthritis is at least 3-to-1 females to males and the incidence of post-polio is much higher for non-Hispanics whites than for any other race/ethnic group), as well as biases in the subject pools (e.g., the hospital pool is biased in favor of lower socio-economic status), the specific combination and levels of stratifying factors used varies by impairment group. The Rancho subject pool is complete with approximately 1700 individuals, not counting spinal cord injury, and was constructed by reviewing the medical records of all polio, R.A., C.P. and Stroke patients seen at the hospital within a five year period (1989 to 1994). The community-based subject pool, which is still being constructed, is based on volunteers recruited from solicitation to disability-related support groups and organizations, strategically selected physicians (primarily rheumatologists), radio public service announcements and word-of-mouth among consumers.

Eligibility Criteria: Although the specific eligibility criteria used to determine inclusion in either of the two subject pools vary by impairment group, general qualifications are based on chronological age, duration of disability, country of residence at time of initial onset, and the presence of some residual impairment. (See the color coded cover pages for all three versions of Part I for a listing of the exact criteria used for each group).

Research Design: The Aging-with-Disability study uses an overall group comparison design, and relies on a cross-sequential framework for both sample selection and data analysis in order to separate out "aging" effects, based on differences in chronological age, from "duration of disability" effects.

For more information on the Aging with Disability Study contact Margaret L. Campbell, PhD, at (310) 401-7402 or by E-mail at <mic@almaak.USC.edu>.