LAUSR

OBJECTIVE To evaluate the test-retest and concurrent validity of the L-test in a group of participants with mild to moderate Parkinson's disease. The L-test is an extended version of the Timed up and Go test, incorporating a longer walking distance and turns in two directions. DESIGN Cross-sectional. SETTING Community. PARTICIPANTS 16 participants (13 male), mean age 75 (SD 6.7) mean duration since diagnosis 7.1 years (±2.8). Disease severity was mild to moderate on the Hoehn and Yahr scale (mean 2.1; mode 2; range 1-3). 14 participants (12 male) completed the study. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES A Bland and Altman plot examined the agreement between first and second testing occasion of the L-test. Intra-class correlation coefficients (ICC) assessed the test-retest reliability. Concurrent validity was established by correlating the L-test with the Timed up and Go test (TUG). The Minimal Detectable Change with 95% confidence interval (MDC95) was calculated to determine the true change not due to chance. RESULTS The L-test showed excellent test-retest reliability on the Bland & Altman plot and the ICC. There was a high degree of agreement between measurements taken on days 1 and 2. The L-test correlated strongly with the Timed up and Go test on both measurement days with r=0.97 (p<0.001) and r=0.96 (p<0.001). The MDC95 was 5.31seconds. CONCLUSIONS The L-test is a reliable and valid outcome measurement for the assessment of walking ability in participants with mild to moderate Parkinson's disease.