Influence of Cognitive Function on Postural Control in Physically Independent Older Women: A Time and Time-Frequency Domain Analysis

Background and Purpose This study aimed to investigate whether different levels of cognitive impairment influence postural control (PC) in physically independent older women, using time domain and time-frequency domain analyses. Understanding this relationship is essential for developing targeted interventions to reduce fall risk in aging populations. Methods A cross-sectional study included 129 women aged ≥ 60 years (mean age: 69), who were physically independent and had not engaged in structured exercise for at least three months. Participants were classified into three groups based on Montreal Cognitive Assessment (MoCA) scores: normal cognition (NC), mild cognitive impairment (MCI), and advanced cognitive impairment (ACI). PC data were analyzed using two distinct methods: time domain analysis and time-frequency domain analysis. The time-frequency analysis categorized postural sway into three frequency bands: low (0.05–0.5 Hz), medium (0.5–1.5 Hz), and high (1.5–10 Hz). Group differences were assessed using one-way ANOVA, preceded by Levene’s test for homogeneity of variances. When variance assumptions were violated, data were log-transformed (base 10) to meet normality requirements. Post hoc comparisons were conducted using the Sidak test. Additionally, effect size was calculated using partial eta squared to evaluate the clinical relevance of the findings. Results Time-domain analysis revealed that participants with better cognitive function exhibited reduced postural sway in BSEO, BIUS, and BIVR conditions. No statistically significant differences were observed in time-frequency domain analysis; however, different frequency band distribution patterns were noted. Lower frequency bands (visual-vestibular system) were predominant in less challenging tasks, while cerebellar (medium frequency) and proprioceptive (high frequency) systems were more active in complex conditions. Clinical relevance analysis confirmed that better cognitive function was associated with improved PC across both analysis methods. Conclusion Cognitive status influences PC, with variations depending on task complexity and analysis method. These findings underscore the importance of incorporating cognitive assessments into balance evaluations and fall prevention strategies for older adults.