Activities of daily living (ADLs) are self-care activities that are important for health maintenance and independent living. ADLs comprise a broad spectrum of activities, traditionally classified as basic and instrumental ADLs (BADLs and IADLs, respectively). BADLs, also called physical or self-maintenance ADLs, are life-sustaining self-care activities such as feeding, grooming, bathing, dressing, toileting, and ambulation. IADLs are more complex activities that are necessary for independent living, such as using the telephone, preparing meals, shopping, managing finances, taking medications, arranging appointments, and driving. These activities are important for participating in one’s usual work, social, or leisure roles.
The evolution of the concept of ADLs is reflected in the development of instruments to measure these abilities (McDowell & Newell, 1996). Measures of BADLs were first developed in the 1940s and 1950s, primarily out of the needs to assess fitness for military duty in World War II and to determine the required levels of care for institutionalized older adults and those with chronic illnesses. These early measures include the PULSES profile, the Barthel Index, and the Katz Index of ADL, among others. Later, in the 1960s and 1970s, there was increased interest in caring for older and disabled individuals in the community, and this spawned the need for tools to measure IADLs that are important for independent living. Some of the first of these measures were Lawton and Brody’s IADL Scale and the Disability Interview Schedule.
ADLs are of interest across various health disciplines. Current knowledge in this area is based on research conducted by psychologists, occupational therapists, nurses, psychiatrists, neurologists, and social workers, among others.
Relevance to Neuropsychology
For the neuropsychologist, an understanding of the patient’s level of independence in ADLs, and in particular IADLs, is of interest for several reasons. The diagnosis of a number of cognitive and mental disorders requires an appraisal of the patient’s functional ability (American Psychiatric Association, 2000). For example, impairment in adaptive or functional ability is a diagnostic criterion for mental retardation and for schizophrenia. Impaired daily functioning is also required for the diagnosis of dementia and is one of the defining differences between dementia (in which IADLs are impaired) and mild cognitive impairment (in which IADLs are intact or minimally affected).
Increasingly, the evaluation of daily functioning is also used to identify appropriate treatments for cognitive and mental disorders. In particular, an important part of determining the effectiveness of behavioral or pharmacological interventions is measuring the impact of the intervention on the patient’s daily functional ability, in addition to cognitive or affective outcomes.
Assessment of ADLs
Assessment of ADLs can be accomplished in a number of ways. Real-world observation of the patient in his or her own home provides relevant, objective information about daily function. However, this method is obviously time and labor intensive, and there are practical limits to the number of behaviors that can be observed within a given time period. An alternative is the use of performance-based measures, which require the patient to complete functional tasks – such as preparing a meal, using the telephone, or making personal financial transactions – that are presented in a standardized way in the laboratory or clinic. A number of such instruments have been developed to measure single or multiple functional domains. Tests include the Direct Assessment of Functional Status, the Independent Living Scales, the Structured Assessment of Independent Living Skills, the Medication Management Abilities Assessment, and many others.
The use of questionnaires administered either on paper or by interview allows the sampling of a large number of behaviors in a short period of time. Self-report questionnaires may be appropriate for use with cognitively-normal or mildly impaired populations. In the evaluation of dementia and other cognitive disorders, however, self-reported abilities may be difficult to interpret because of disease-related decreases in self-awareness. The use of informant-based questionnaires avoids this limitation, although informants can also be biased in their reports and may not always be available. Nevertheless, this is one of the most common methods for measuring IADLs, and a large number of informant-based questionnaires exist, such as the Lawton-Brody IADL Scale, the Bristol ADL Scale, and the ADL questionnaire.
The choice of which particular method of assessment to be used will depend, in addition to practical considerations such as time, on the purpose of the assessment. Real-word observations and performance-based measures provide information about what the person is capable of doing. Questionnaires, on the other hand, measure what the individual is actually doing in his or her day-to-day life.
Although there are a large number of relevant instruments that have been developed to assess ADLs, they vary in terms of how well their psychometric properties have been characterized. Systematic literature reviews (e.g., Moore, Palmer, Patterson, & Jeste, 2007; Sikkes, de Lange-de Klerk, Pijnenburg, Scheltens, & Uitdehaag, 2009) indicate that, for many of these measures, there is a need for better theoretical justification of the content of the instrument, additional information about test validity and reliability, indication of what constitutes a meaningful change over time, information about the relation between test performance and actual real-world functioning, and the development of comprehensive normative data.