Cerebral amyloid deposition and dual-tasking in cognitively normal, mobility unimpaired older adults

Abstract

Background: We examined relationships between cerebral amyloid-beta (A?) and cognitive-gait dual-task performance in 27 cognitively normal, mobility unimpaired elders. Methods: We assessed A? on Pittsburgh Compound B (PiB)-PET. We measured gait speed separately and while performing working-memory, response-inhibition, motor-sequencing, and phone-dialing tasks. We compared dual-task costs on gait and cognitive performance in high-A? (PiB(+)) and low-A? (PiB(?)) groups and examined the association between A? and dual-task performance decrements. Results: PiB(+) (n = 16) were comparable with the PiB(?) (n = 11) individuals on demographics, general cognitive and physical performance, and key brain MRI characteristics. PiB(+) group demonstrated greater dual-task costs on gait speed on all cognitive tasks (p < .05) except on response inhibition. Dual-task costs on cognition were similar between groups. Overall, A? was associated with dual-task decrement on gait speed but not on dual-task decrement on cognitive performance. Conclusions: Preliminary evidence indicates that cerebral A? is associated with gait slowing on dual-tasking in healthy older adults.