Functional Mobility and Its Relationship With Cognition in Older Adults With Normal Cognition, Motoric Cognitive Risk Syndrome, and Mild Alzheimer's Disease.

Abstract

Background and purpose: Motoric cognitive risk syndrome (MCR) is a predementia syndrome and is a strong predictor of Alzheimer's disease (AD). Functional mobility, such as balance, sit-stand transitions, and turning, has not been clearly investigated in this population. This study aimed to compare functional mobility among older adults with normal cognition (NC), MCR, and mild AD. Cognitive-motor interactions were also investigated in all the groups.

Methods: This cross-sectional study included 91 older adults, including 36 with NC, 32 with MCR, and 23 with mild AD. A battery of neuropsychology tests encompassing several domains, including general cognition, executive function, attention, episodic memory, visuospatial performance, and language, was administered, and functional mobility tasks, including the Short Physical Performance Battery (SPPB) and the Timed Up and Go Test (TUG), were also carried out. Differences between groups were analyzed with MANCOVAs (post hoc Bonferroni correction). Partial correlation analysis adjusted for age and education levels was used to examine correlations between functional mobility and cognitive function in each group. Canonical correlation analyses were used to determine the extent of the relationship between a set of cognitive variables (executive function, attention, and visuospatial performance) and a set of functional mobility variables (the SPPB and TUG) in the NC, MCR, and mild AD groups.

Results and discussion: The SPPB and TUG performance of the MCR and mild AD groups was significantly worse than that of the NC group. Visuospatial performance and depression were significantly correlated with functional mobility in the MCR group, while depression was the only specific cognitive aspect associated with functional mobility in the mild AD group. Canonical analysis demonstrated a significant relationship between cognition and mobility, explaining approximately 28.4% of the variance, in the NC group. However, the other two groups showed no significant correlation between cognition and mobility.

Conclusions: In addition to slow gait, deficits in sit-stand transitions and turning were also observed in the MCR and mild AD groups. We also found that motor-cognitive interactions may differ according to the level of cognitive impairment. Future studies should comprehensively assess functional mobility for different cognitive impairment populations.