Functional Ability

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In the course of daily life, people get out of bed, take baths or showers, use the toilet, dress, prepare meals, and eat. These types of basic functions allow people to socialize, work, or engage in a myriad of other productive and social activities. In the lexicon of gerontology, these fundamental self-care activities have been labeled activities of daily living, or ADLs. Although mundane and ordinary to most of us, the capacity to perform such activities has been confirmed in numerous studies to have broad implications for functioning, reflecting a person's ability to live independently in the community.

Disability or functional impairment refers to a person's inability to perform these and other basic tasks without assistance, whether due to aging, illness, accident, or conditions at birth. Long-term care services are designed to compensate for an individual's disabilities or functional impairments, or, when possible, to restore or improve functional abilities. In an important sense, functional limitations are the raison d'etre for long-term care.

Two basic levels of functional ability are recognized. The most basic ADLs in the areas of personal care and mobility (e.g., eating, bathing, dressing, using the toilet, and transferring from bed or chair) are distinguished from more complex role activities, such as taking medication, managing money, and grocery shopping, which have come to be known as instrumental ADLs (IADLs). The basic ADLs were first proposed in 1959 as a cluster of basic physical functions that are useful benchmarks for gauging the effects of rehabilitation. IADL measures were developed in the late 1960s. The IADLS are more heterogeneous than ADLs, and include activities necessary to live independently in the community, such as using a telephone, taking medications, managing money, grocery shopping, meal preparation, shopping, light and heavy housework, doing laundry, using local transportation, and remembering appointments.

The consequences of an assessment of functional ability are extremely personal, and yet they also contain broad policy and practice implications. For many older adults who have entered the formal service system for help, the results often require coming to grips with a loss of, or decline in, functioning in one or more areas where previously they had been independent. At the same time, the use of functional impairment as an eligibility criterion for long-term care services is widespread. Impairment eligibility standards vary from state to state, but are usually defined as needing assistance in two or three ADLs. Most states have created their own ADL measures, although these usually rely on other previously established measures.

A number of comprehensive reviews of functional ability have been completed. Among recent reviews, Mary G. Kovar and M. Powell Lawton provide an excellent review of functional disability (in M. Powell Lawton and Jeanne A. Teresi's edited volume Focus on Assessment Techniques [1994]), and Laurence G. Branch and Helen Hoenig offer a succinct review of measures of physical functioning in Generations (1997). Another review that has stood the test of time is Rosalie and Robert Kane's Assessing the Elderly: A Practical Guide to Measurement (1981).

Measuring functional ability poses a variety of challenges. One important issue is that environmental factors strongly influence responses to ADL and IADL measures. For example, someone who uses a wheelchair may be perfectly able to drive or use local transportation, but may be unable to leave the house due to an inability to negotiate stairs. Whether an individual has difficulty getting to and using the toilet may depend on whether there is a toilet easily accessible, and on whether there are physical aids such as grab rails. In some residential settings, a resident may have the capacity to cook, but have no opportunity to do so. A resident may be able to bathe independently, but may live in a facility in which the rules require that all residents receive assistance with bathing. Asking about a respondent's latent ability to perform a task ("Can you. . .?") has the advantage of addressing barriers in the environment or other contextual factors that may inhibit performance, but such an approach sometimes gives a misleading impression of the respondent's actual performance of ADL tasks. People may not do what they are physically capable of doing because of preferences or cultural reasons. Asking what ADL tasks someone actually does ("Do you. . .?") can provide a better picture of what supports are needed to promote functional ability.

One of the most important dimensions of function ability is dependence. Dependence indicates whether an individual needs or uses the assistance of another person or special equipment to accomplish the task. Dependency, by its very nature, implies the use of formal or informal services that are used in response to disability. One of the most common approaches to determine dependency is to assess how much assistance or help a person requires to perform an activity. Each activity can be rated on a three-point scale of independence: (1) no assistance required, (2) partial assistance required, and (3) total assistance required (or does not do the activity). Another approach is used to assess how difficult or "hard" it is to perform a task or activity. For example, in the Longitudinal Study of Aging (LSOA), a large probability study of the noninstitutionalized elderly, respondents were asked the following question for each activity: "Because of a health or physical problem, do you have any difficulty performing [the activity]." Respondents who reported having some difficulty were asked: "By yourself, and without using special equipment, how much difficulty do you have [performing the activity]: some, a lot, or are you unable to do it?" Respondents were considered functionally impaired if they reported some difficulty or assistance needed in performing one or more tasks.

For programs wishing to assess functional ability, it is preferable to use one of the many already established scales that have been proven to be valid and reliable. Beyond that, a number of additional steps can be taken to improve the accuracy of the assessment and the utility of the results. For example, it is helpful to explicitly include the type of wording that could be used to address the client or respondent in order to standardize the way the questions are asked. It is also important to clearly define in nontechnical language key words or phrases such as activities of daily living, grooming, and transferring. Assessors too often assume that respondents understand these terms and use them during the course of the assessment, when in fact they are technical terms that may not be clearly understood. Program staff may also need more information than the choices provided in standardized measures. If a client has problems in using the toilet, it will be important to know whether the person has bowel or bladder incidents, whether these occur during the day or night, and how often. This issue can be addressed by allowing space next to each item for comments to describe the problem and what type of assistance is needed, or this type of information can be built into the wording of the items. Additionally, programs may need to add items that address particular service issues or concerns. For example, some IADL measures distinguish between answering the telephone and making a telephone call, and between light housework and heavy housework, and others have added items about laundry, using local transportation, and remembering appointments.

Accurately assessing the functional ability of older adults is a major challenge. The wide use of measures of functional ability belies the difficult measurement issues involved. When properly used, these measures can assure that frail older adults receive the assistance they need to live independently, consistent with their values and preferences. However, all persons are at risk from assessments that they think are accurate, but are not. Clients and their families rely on the accuracy of assessment protocols, and there is a natural tendency to trust formally sanctioned assessments. The term functional assessment has a ring of scientific legitimacy, and the results are presumed to be accurate, but this is not always so. Programs use measures of functional ability to determine eligibility for services, and sometimes to justify the need for other important tests, treatments, or interventions. How well this assessment is made has profound implications for the person assessed and for public policy.

Scott Miyake Geron

See also Assessment; Frailty; Long-Term Care.


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