Age Moderates Differences in Performance on the Instrumented Timed Up and Go Test Between People With Dementia and Their Informal Caregivers

Background and Purpose: The instrumented Timed Up and Go test (iTUG) affords quantification of the subelements of the Timed Up and Go test to assess fall risk and physical performance. A miniature sensor applied to the back is able to capture accelerations and velocities from which the subelements 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 iTUG 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: younger than 70 years, 70 to 79 years, and 80 years and older. Participants wore an inertial sensor while performing the iTUG in their home. The performance of the subelements 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 was compared with caregivers for each age-matched group, and multiple regression models incorporating age, gender, and presence or absence of dementia were computed. Results: People with dementia took longer to turn in the younger than 70-year group, suggesting this may be an early indicator of functional decline in this age group. People with dementia took longer to complete the whole iTUG compared with caregivers in the 70- to 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.