Research Corner: Outcome Measures in Cardiopulmonary Physical Therapy: Focus on the Glittre ADL-Test for People with Chronic Obstructive Pulmonary Disease

Abstract

The primary goal of physical rehabilitation for people with chronic lung disease, including chronic obstructive lung disease (COPD), is to improve function. In terms of the International Classification of Functioning, Disability and Health (ICF),1 physical therapy typically focuses on improving activity, which may result in increased participation in pursuits that are meaningful to the individual. A commonly used and related concept is functional status. Keith2 described functional status as “physical function including activity restrictions and fitness; psychological function including affective and cognitive functioning, social function including limitations in usual roles or major activity, social integration, social contact, and intimacy.” There are 2 primary methods of assessing functional status—questionnaires and performance-based tests. The most frequently used tools are questionnaires. Generic questionnaires such as the Functional Status Questionnaire,3 Extended Activities of Daily Living scale,4 and the SF-365 are available. However, disease specific questionnaires such as the Chronic Respiratory Questionnaire,6 the St. George's Respiratory Questionnaire,7 and the Pulmonary Functional Status and Dyspnea Questionnaire8 are commonly used for people with chronic lung disease. Questionnaires are generally inexpensive, quick to administer, and allow patients to express their perception of their function. However, there are a number of disadvantages associated with the use of questionnaires.9–12 Specifically, patients' responses may be affected by social and personal expectations of the purpose of the questionnaire. Also, responses may change depending on a patient's cognition or psychological status. In some circumstances, patients may state that they are capable of completing a task but do not consider the time required to complete the activity. Without additional information that is difficult to quantify, a patient may appear to function well when this is not the case. Another difficulty associated with the use of questionnaires is that disease progression in people with a chronic disease may result in activity limitation that could decrease the symptoms of interest. Such a change could erroneously be interpreted as an improvement in health status. For instance, people who experience dyspnea while climbing stairs may stop doing this activity and take the elevator instead. When questioned, this person may no longer report dyspnea when climbing stairs. The person may not be trying to hide the truth, but may have forgotten the discomfort once it no longer occurs. Objective, performance-based tests avoid many of the difficulties noted above. The six-minute walk test (6MWT) is the most frequently used objective test of functional capacity for people with respiratory disease.13 Patients are told to walk as far as possible, in 6 minutes, over a 100 foot, level, indoor course. The psychometric properties of the test have been examined in detail and the test has been shown to be a reliable measure of the distance walked in people with COPD when it is conducted according to standardized guidelines.13,14 The length of the hallway used for the walk,15 the instructions given to the subject,16 the type and amount of encouragement given,16 and the number of learning trials17 have all been shown to affect test performance and reliability. The test is simple to administer and generally well accepted by patients but it does not assess how walking ability affects functional status or participation, as it is defined in the ICF model. Furthermore, it does not assess how dyspnea during unsupported arm activities8,18,19 such as making beds, shelving dishes and doing the laundry affects functional status. As the prevalence of COPD in women increases20–23 the definition and assessment of function will likely need to expand to include more of these activities of daily living (ADL). Most objective tests of physical performance, like the 6MWT, focus on mobility dysfunction or on people having severe limitations.24–27 In contrast, the Assessment of Motor and Process Skills (AMPS) is a 26 item test that measures the quality of a person's activities of daily living (ADL).28 Unfortunately, the test is time consuming to conduct and it would be exhausting for many people with COPD. Furthermore, the assessment of process ability that is an integral part of this test is not usually relevant for people with COPD. The AMPS has not been validated in people with COPD in whom dyspnea plays a significant role in limiting function. Thus the Glittre ADL test was developed to address the need for a more representative, objective assessment of function in people with COPD.12