| Objective: To explore the balance performance and cortical activation characteristics in elderly and young individuals under different sensory strategies while performing cognitive-balance dual tasks. Methods:A total of 19 healthy young individuals and 20 healthy elderly individuals were recruited from the community. The participants naturally stood on a dynamic and static balance apparatus, wearing functional near-infrared spectroscopy (fNIRS) caps to measure cortical activity. They completed three tasks.Task 1 involved standing on a stable surface with eyes closed while performing serial subtraction by sevens.Task 2 involved standing on an unstable surface with eyes open while performing serial subtraction by sevens.Task 3 involved standing on an unstable surface with eyes closed while performing serial subtraction by sevens. The bilateral sensorimotor cortex（SMC）, premotor cortex（PMC）, and prefrontal cortex（PFC） were set as regions of interest (ROIs). The overall stability index (OSI) was used to measure balance ability, and the cortical activation β value was used to measure the degree of cortical activation. Results: In Task 1, the OSI of the elderly group was significantly higher than that of the young group (P<0.05), indicating poorer balance performance. There was no significant difference in the β values between the young and elderly groups, suggesting similar levels of cortical activation. In Task 2, there was no significant difference in OSI between the young and elderly groups. However, the β values of the right sensorimotor cortex (rSMC), right premotor cortex (rPMC), and left prefrontal cortex (lPFC) in the elderly group were significantly higher than those in the young group (P<0.05), indicating increased cortical activation in these areas for the elderly. In Task 3, the-re was no significant difference in OSI between the two groups, but the β values of the rSMC and rPMC in the elderly group were significantly higher than those in the young group (P<0.01). Conclusion: The findings suggest that under dual-task conditions, the elderly rely more on visual input to maintain balance compared to the young. As the complexity of sensory strategies in-creases, the elderly show compensatory increases in cortical activation to enhance the central nervous system’s processing ability for sensory strategy changes. However, due to brain aging and the decline in cortical function, the elderly reach the upper limit of cortical resource utilization more easily. |
