Mobile EEG Reveals Age-Dependent Cognitive-Motor Interference with Increasing Motor Task Complexity- a...

This study examined age-related differences in behavior and brain dynamics underlying cognitive-motor interference (CMI) during motor dual-tasks (DT) with increasing motor task complexity. Behavioral performance and electrocortical activity were assessed in 19 younger adults (11 males, 8 females; 25.5 ± 2.3 years) and 11 older adults (6 males, 5 females; 72.6 ± 4.6 years) using mobile electroencephalography (EEG). Participants performed an oddball choice-reaction task under three conditions: sitting, standing, and treadmill walking. Event-related potential (ERPs; P1, N1, P3) amplitudes and latencies, response times, postural sway, and gait parameters were recorded to evaluate CMI. Data were analyzed using repeated-measures ANOVAs with within-subject factors of motor condition and stimulus type and age group as a between-subject factor. Older adults exhibited reduced step length compared to younger adults, but no DT-related changes in gait or postural sway were observed. Response times were generally slower in older adults and increased from sitting to standing and walking whereas younger adults showed slowing only from sitting to standing. Early sensory ERP components (P1, N1) demonstrated increased amplitudes with higher motor demands. The P3 component was reduced in amplitude in both groups during walking, with delayed latencies in older adults. For both groups, P3 latencies were associated with prolonged response times. Our findings suggest that this slowing during walking reflects altered cognitive resource allocation, characterized by delayed central information processing and enhanced early visual processing, rather than impaired peripheral motor coordination.