Cortical Activity During Postural Recovery Under Dual-task Conditions: A Quantitative EEG Study

Introduction: This study aimed to investigate the cortical activity differences between healthy older adults and younger individuals during postural adjustments in response to external perturbations under both single-task (ST) and dual-task (DT) conditions. Methods: Nineteen young adults (mean age: 24.25±3.15) and 20 older adults (mean age: 65.55±4.67 years) were recruited. Participants stood barefoot while a load (3% body weight) was unpredictably released, inducing postural perturbations. In DT trials, participants performed a cognitive task (counting backward) while maintaining balance. Quantitative electroencephalography was recorded from 32 channels, focusing on cortical regions involved in postural control (e.g. motor and sensorimotor cortices). Alpha (8-12 Hz) and beta (12.5-25 Hz) absolute power in specific brain regions (C3, C4, Fz, Cz, Pz) were analyzed using a 3-way mixed-design analysis of variance. Results: Older adults exhibited significantly higher alpha power in sensorimotor areas (C4, Pz) during DT conditions, compared to younger adults. Group×condition interactions revealed greater beta power in the frontal and central regions (F4, C4) in older adults under DT conditions. Post hoc analysis indicated significantly greater beta power in older adults during DT than in younger individuals. Conclusion: These findings suggest that older adults rely more on cortical resources for postural recovery, particularly under cognitively demanding DT conditions. The increased alpha and beta power in cortical regions reflects a shift towards compensatory cortical strategies, likely due to age-related declines in automatic postural control mechanisms. Understanding these neural changes can inform fall prevention strategies targeting both cognitive and motor functions in older adults.