Influence of cognitive function on postural control in physically independent older women: a time and time-frequency domain analysis

BACKGROUND AND PURPOSE: This study examined whether different levels of cognitive impairment influence postural control (PC) in physically independent older women, using complementary time domain and time-frequency analyses. Understanding these associations may help identify early markers of cognitive vulnerability and guide preventive strategies aimed at reducing fall risk in aging. METHODS: A cross-sectional sample of 129 women aged ≥ 60 years (mean age 69), physically independent and not engaged in structured exercise for at least three months, was categorized into three groups according to Montreal Cognitive Assessment (MoCA) scores: normal cognition (NC), mild cognitive impairment (MCI), and advanced cognitive impairment (ACI). PC was assessed through time domain variables, mean sway velocity (anteroposterior and mediolateral) and the area of the center of pressure (A-COP), and through time-frequency parameters categorized into low (0.05-0.5 Hz; visual-vestibular contribution), medium (0.5-1.5 Hz; cerebellar modulation), and high (1.5-10 Hz; proprioceptive contribution) frequency bands. Confirmatory analyses for the primary conditions (BSEO and BIUS) were performed using ANCOVA adjusted for age, body mass index (BMI), Charlson Comorbidity Index (CCI), and Falls Efficacy Scale (FES) scores. Exploratory outcomes were analyzed with one-way ANOVA, followed by Sidak-adjusted post hoc tests. Effect sizes were estimated using partial eta squared. RESULTS: Time domain analyses showed that women with better cognitive performance demonstrated better postural control, reflected by lower sway velocity, particularly in the BSEO and BIUS conditions. Exploratory analyses also identified group differences in the BIVR condition. Although the time-frequency analyses did not reveal statistically significant differences between groups, the descriptive patterns suggested that lower-frequency components were more evident during less demanding tasks, whereas medium and high frequency components appeared more prominent in more challenging conditions. Effect-size estimates supported the clinical relevance of time domain differences between cognitive groups. CONCLUSION: Cognitive status influences postural control in physically independent older women. Time domain measures, particularly sway velocity, were sensitive to poorer balance among those with cognitive impairment, while time-frequency parameters did not differentiate cognitive groups. These findings highlight the importance of incorporating cognitive screening into balance assessment and fall-prevention strategies in aging populations.