impaired. The combined findings of these studies4–6 and the previously noted clinical observation suggest that test-retest reliability of physical and functional performance measures with individuals with AD may be influenced by level of dementia.
The purposes of this research were: (1) to determine test-retest reliability of data for the TUG, the 6MWT, and gait speed with individuals with AD; (2) to determine MDC scores for each of the outcome measures; and (3) to identify performance differences between participant groups stratified by level of dementia.
The existing literature guided the choice of outcome measures for the present study. We hypothesized that the test-retest reliability of the clinical tools would decrease with increased level of dementia, such that the measures would be reliable for use with individuals with mild to moderate AD, but not for use with individuals with moderately severe to severe AD. We also hypothesized that, when stratified by level of dementia, the participants who were less cognitively impaired would perform better on the clinical tests
compared with the participants who were more cognitively impaired.