BACKGROUND: Dual-task (DT) walking poses great challenges to gait control in older adults with mild cognitive impairment (MCI). However, the integrated adaptive characteristics of cortical, muscular, and gait responses under DT interference remain insufficiently elucidated. OBJECTIVE: This study aimed to compare gait performance, cortical activation, and muscle activation characteristics between older adults with MCI and cognitively intact controls during DT walking. METHODS: A total of 25 MCI older adults and 25 cognitively intact controls were recruited and completed single-task (ST) and DT walking tests. The DT condition involved performing a continuous subtraction task (subtracting 3 from a random number between 400 and 500) while walking. Data were collected using functional near-infrared spectroscopy, a 3D motion capture system, and surface electromyography to quantify cortical activation, gait parameters, and lower-limb muscle activation. RESULTS: Under the DT walking condition, the MCI group showed significant gait impairments, including decreased gait speed, increased step width, and altered gait variability. Among the examined bilateral cortical regions, significant Group × Task interaction effects in cortical activation were observed in the left prefrontal cortex, left primary motor cortex, and left supplementary motor area, indicating altered task-related cortical activation patterns in older adults with MCI during DT walking. In addition, rectus femoris activation was significantly higher in the MCI group than in controls during DT walking. CONCLUSION: DT walking induced noticeable gait impairments in older adults with MCI, which were accompanied by adjustments in cortical control patterns and increased muscular activation. However, these potential compensatory responses, characterized by increased muscle activation and altered cortical regulation, appeared insufficient to fully mitigate the negative effects of cognitive load on gait performance, suggesting reduced gait automaticity in older adults with MCI. TRIAL REGISTRATION: ChiCTR2500105909, 7/14/2025.
Li et al. (Mon,) studied this question.