comparative analysis of balance control strategies and center of pressure complexity in parkinson's disease and healthy individuals

Background: balance impairment is a prominent and disabling feature of parkinson’s disease (pd), contributing to reduced mobility and increased fall risk. a clearer understanding of postural control strategies and the balance variables most sensitive to pd may help in designing targeted interventions. this study aimed to compare balance-related measures and postural regulation strategies between individuals with pd and neurologically healthy adults.methods: using g*power, the required sample size was estimated, and participants were recruited through purposive and convenience sampling. fifteen individuals with pd and seventeen healthy controls completed the protocol. postural control was assessed with a kistler force platform across four standing conditions that manipulated surface stability and vision. center of pressure (cop) data were collected for 20 seconds at 1000 hz. variables in both ap and ml directions were analyzed, including spatial measures (cop displacement, sway, rms), quantitative measures (acceleration, velocity), and complexity (sample entropy). a sit-to-stand (sts) task was also evaluated.results: manipulating the base of support (bos) significantly affected spatial cop measures and complexity in both groups (p<0.05). during the sts task, quantitative variables were higher in controls compared to the pd group (p<0.05). complexity values were consistently higher in individuals with pd across all conditions (p<0.05).conclusions: overall, the increased sway magnitude and elevated irregularity in the pd group suggest reliance on more conscious and less automatic postural control strategies, reducing adaptability to environmental changes and potentially elevating fall risk under unstable conditions. moreover, complexity and quantitative sts measures appear sensitive to pd, while spatial variables show strong responsiveness to bos manipulation and visual dependence across balance tasks.