Age Moderates Differences in Performance on the Instrumented Timed Up and Go test between People with Dementia and their Informal Caregivers.

Abstract

Introduction The instrumented Timed Up and Go test (iTUG) affords quantification of the subelements of the Timed Up and Go test to assess falls risk and physical performance. A miniature sensor applied to the back is able to capture accelerations and velocities from which the sub-elements of the iTUG can be quantified. This study is the first to compare iTUG performance between people with dementia (PWD) and their age matched caregivers. The aims of this study were to explore how age moderates the differences in performance on the instrumented Timed Up and Go test between PWD and their informal caregivers. Methods Eight-three community dwelling older PWD and their informal caregivers were recruited for this cross sectional, observational study. Participants were grouped by age; <70 years, 70-79 years and 80+ years old. Participants wore an inertial sensor while performing the iTUG in their home. The performance of the sub-elements sit to stand, walking and turning were captured through an algorithm converting accelerations and velocities into performance metrics such as duration and peak velocity. Performance for PWD were compared to caregivers for each age matched group and multiple regression models incorporating age, gender and presence or absence of dementia were computed. Results PWD took longer to turn in <70 year group, suggesting this may be an early indicator of functional decline in this age group. PWD took longer to complete the whole iTUG compared to caregivers in the 70-79 year old group. In the 80+ year old group PWD took longer to complete both walking phases, sit-to-stand and the full iTUG along with displaying slower turning velocity. Multiple regression models illustrated that gender failed to contribute significantly to the model, but age and presence of dementia explained around 30% of the variance of time to complete walking phases, total iTUG and turning velocity. Conclusions Differences were evident in performance of the iTUG between PWD and caregivers even after controlling for age. Age moderates the differences observed in performance.