Physicians are frequently asked to render an evaluation of pulmonary disability. Examples include the cigarette smoker with severe emphysema who is no longer able to do his or her strenuous job, the auto body worker with isocyanate-induced asthma, the retired coal miner with pneumoconiosis, the business executive with severe sleep apnea interfering with his or her ability to function effectively in the office, and the asbestos worker with lung cancer. An approach to the evaluation of these patients will be presented here. The evaluation and management of the specific conditions noted above are reviewed separately. (See appropriate topic reviews).
Although the terms "impairment," "disability," and "handicap" are often used interchangeably by doctors and patients, these terms have precise and distinct definitions with regard to disability evaluation.
Impairment — According to the World Health Organization (WHO), impairment refers to "any loss or abnormality of psychological, physiological, or anatomical structure or function" . When possible, impairment of pulmonary function is measured by quantitative means such as spirometry, diffusing capacity for carbon monoxide (DLCO or Transfer factor), arterial blood gases, and integrated cardiopulmonary exercise testing. Assessment of bronchodilator response and nonspecific bronchial hyperresponsiveness (eg, by methacholine inhalation testing) are also used in special circumstances, such as asthma. Thus, the assessment of impairment is primarily the responsibility of a clinician familiar with these physiologic parameters of breathing function . (See "Overview of pulmonary function testing in adults" and "Bronchoprovocation testing".)
Disability — The WHO definition for disability refers to "any restriction or lack of ability to perform any activity within the range of 'normal' for a human being" . The American Thoracic Society (ATS) definition refers to the "total effect of an impairment on a patient's life" [3-5]. Thus, disability is not only assessed by objective quantitative measures of pulmonary function, but also incorporates such diverse factors as age, gender, education, and both economic and social environment. Two individuals with the same degree of physiologic impairment may have quite different levels of disability, based upon the requirements for their vocational and avocational activities. Disability assessments must also take into account those personal characteristics that may affect an individual's ability to retrain for alternative work.
Handicap — The WHO definition for handicap is "disadvantage resulting from an impairment/disability that limits/prevents fulfillment of that person's normal role depending on sex, age, social, and cultural factors" . Thus, this definition overlaps with the ATS definition of disability.