Abstract
The methods and rationale used to establish reliability and validity of functional status assessments (FSAs) were reviewed with specific reference to clients with cerebrovascular disease. There exists some confusion in the literature regarding the evaluation of impairment versus the assessment of disability. The impairments rated by some FSAs included measures of muscle tone, reflex changes, and abnormal synergies. In contrast, the assessments of disability addressed deficits related to ambulation, transfers, and other activities of daily living. A clear relationship between impairment and disability has not yet been established. The majority of studies described reliability by reporting some correlational measure, but only three of six studies measured agreement between raters. Criterion-related validity was the most widely utilized form of validity testing described in the studies reviewed. The use of criterion measures such as the extent of cerebral lesion or the pattern of electromyographic activity were found empirically to be weak indicators of function. Therefore, correlations of a proficiency index of activities of daily living with these criterion measures of function did not necessarily provide support for validity. It is recommended that future studies clarify the distinction between disability and impairment and report chance-corrected measures of agreement when describing the reliability of discrete outcome scales.