Reliability and validity of the extended timed-get-up-and-go test in patients with bilateral vestibular loss

BACKGROUND: The aim of his study was to evaluate the reliability and validity of the Expanded Timed Get-up-and-Go (ETGUG) test in patients with bilateral vestibular loss (BVL). METHODS: 21 BVL patients (58 +/- 14 years) were recruited and measured twice by two raters. After a one hour break ETGUG was repeated by the first rater. 21 age matched controls (CON; 58 +/- 14 years) were measured once by the first rater. All time scores of the ETGUG for the separate tasks and gait speed calculated from tasks 3 and 5 were analysed to determine relative and absolute reliability, smallest detectable change (SDC) and discriminatory capabilities. RESULTS: The ETGUG scores showed good to excellent inter-rater (ICC2,1 = 0.85-0.97) and test-retest reliability (ICC3,1 = 0.86-0.98) following log-transformation for tasks 2-6. Task1 scored fair r = 0.46-0.68. The SDCs were small (SDC = 0.05-0.21 seconds). Bland-Altman plots demonstrated good agreement between the measurements. There were significant differences between BVL and CON in ETGUG scores for tasks 1, 3, 4, 5, 6 & overall time. Task 2 showed no difference between the groups. BVL patients walked slower compared to the age-matched controls. DISCUSSION: Good reliability of the ETGUG in BVL and an indication for the discriminatory capabilities for the separate tasks suggest that the ETGUG could facilitate the study of functional deficits in BVL patients. Good reliability, small measurement error and values of SDC warrant the further utilisation of the ETGUG for the evaluation of physical functioning in BVL patients.