Gait characteristics in preclinical Alzheimer’s disease: Preliminary results of the RADAR‐AD study

Background The Remote Assessment of Disease and Relapse – Alzheimer’s Disease (RADAR‐AD) study is assessing functional decline in Alzheimer’s Disease (AD) using remote monitoring techniques (RMT’s). RMT’s allow for continuous and objective monitoring of function, potentially improving the sensitivity of assessment in AD. Gait is an important functional domain to maintain independent living. Yet, relatively little is known on gait impairments in the pre‐symptomatic stages of AD. Therefore, the aim of this study is to compare outcomes of in‐clinic gait assessments, using high frequency inertial measurement units, between healthy controls, preclinical AD patients, and cognitively impaired AD patients. Method We included early data from amyloid negative cognitively healthy participants (controls, n=9), amyloid positive cognitively healthy participants (preclinical AD, n=6) and amyloid positive cognitively impaired participants (n=3) participants (Table 1) from the RADAR‐AD study. Participants performed a one‐minute walking task, a one‐minute dual task (walking while counting backwards from 100) and timed up‐and‐go (TUG) task, while wearing GaitUp Physilog sensors 1 on the left foot, right foot, and right hip. Metrics provided by the sensors include gait speed, steps per minute, double support time, and TUG task completion time. Result Regression analyses with models corrected for age, sex, and education revealed no between‐group differences on the main outcomes. However, the preclinical AD group showed several interesting near‐significant trends that warrant further investigation (Figure 1). This included an apparent smaller difference in gait speed between the walking task and dual task compared to controls (β=‐10.78 (5.8), p=0.09), accompanied by a smaller difference in steps per minute (β=‐9.27 (5.05), p=0.09), and a larger difference in double support time (β=14.32 (7.28), p=0.07). Conclusion Although no between‐group differences in gait outcomes were found in this initial data, early near‐significant trends in the preclinical AD group appears to show altered gait patterns in particular during the dual task. These preliminary findings will be further investigated on possible pathological causality of such behavior as our dataset increases. Inclusion in the RADAR‐AD study is ongoing, and subsequent analyses will include larger sample sizes, more in‐depth analyses of gait behavior, and associations with rating scales of mobility. Reference: [1] https://research.gaitup.com/physilog/