Postural sway, falls, and cognitive status: a cross-sectional study among older adults.

BACKGROUND: Cognitive impairment-related changes in postural sway increase fall risk among older adults. Better understanding this association could be helpful for fall prevention.

OBJECTIVE: To examine the center-of-pressure (COP) velocity association with cognitive status and history of falls, in cognitively healthy individuals (CHI), patients with mild cognitive impairment (MCI), and with mild-to-moderate Alzheimer's disease (MMAD).

METHODS: Six hundred and eleven older community-dwellers (77.2 ± 7.9 years; 51.8% men) were separated into CHI, MCI, and MMAD participants. By computing the average absolute maximal velocity (AAMV), the bounding limits of COP velocity dynamics were determined while participants were asked to maintain quiet stance on a force platform with eyes open or with eyes closed. Age, gender, history of falls, body mass index, medications, handgrip strength, Timed Up & Go score were used as covariates.

RESULTS: The multivariate ANCOVA, with AAMV in eyes open and eyes closed conditions as dependent variables, showed that the highest AAMVs that bound the COP velocity dynamics of postural sway were associated with cognitive impairment (p = 0.048) (i.e., lowest limits in CHI and MCI as compared with MMAD) and falls (p = 0.033) (i.e., highest limits in fallers).

CONCLUSIONS: These findings identified the bounding limits of COP velocity as a hallmark feature of cognitive impairment-related changes in postural sway, in particular for MMAD. This point is of special interest for clinical balance assessment and fall prevention in MMAD patients in order to plan long-term targeted fall-prevention programs.