?-Amyloid Burden Predicts Lower Extremity Performance Decline in Cognitively Unimpaired Older Adults.

ABSTRACT:

Background

Motor slowing is associated with risk of Alzheimer's disease. Whether ?-amyloid (A?) burden is associated with motor decline, independent of cognitive decline, is unknown.

Methods

About 59 cognitively unimpaired older participants had baseline PET-PiB scans and repeated measures of lower (usual gait speed, 400-m time, Health ABC Physical Performance Battery (HABCPPB) score, total standing balance time) and upper (mean tapping time) extremity performance during a mean follow-up of 4.7 years. Linear mixed effect models examined the relationship between baseline A? burden and motor decline, adjusting for age, sex, body mass index, cardiovascular risk, APOE ?4 status, memory decline, depressive symptoms, ankle-arm index, processing speed, executive function, and cerebrovascular disease.

Results

Higher mean cortical A? burden was associated with greater declines in gait speed and HABCPPB score and a greater increase in 400-m time. Higher A? of putamen was associated with declines in all lower extremity measures, including balance. Higher A? of dorsolateral prefrontal cortex and lateral temporal lobe was associated with declines of gait speed and 400-m time, and of precuneus with a greater increase in 400-m time. Associations remained similar after further adjustment.

Conclusions

In cognitively unimpaired older adults, A? burden overall and in specific brain regions are risk factors for lower extremity motor decline, independent of memory function. These findings provide the first empirical evidence that A? burden is a risk factor for mobility decline in older adults.

SUBMITTER: Tian Q 

PROVIDER: S-EPMC6075426 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature