Gait speed-related changes in electrocortical activity in younger and older adults

Preferred and maximum walking speeds decline as we age, and the decline has been associated with worsening health. Slowing of gait in older individuals is correlated with biomechanical and neural factors, but historically it has been difficult to measure whole brain activity during walking. Recent advances in mobile brain imaging with high-density electroencephalography (EEG) allow for separation and localization of electrical brain activity during walking. We studied younger (N = 31) and older (N = 59) adults walking on a treadmill at different speeds (0.25-1.0 m/s) while we recorded electrocortical dynamics with EEG. We hypothesized that faster walking speeds would result in greater sensorimotor and posterior parietal theta-band (4-7 Hz) spectral power and lower beta-band (13-30 Hz) spectral power compared to slower walking speeds for older adults, consistent with previous studies on younger adults. Additionally, we used a standardized test of physical function to group older adults into high-functioning [Short Physical Performance Battery (SPPB) ≥ 10] and low-functioning (SPPB < 10) groups for comparison. In agreement with our hypotheses, sensorimotor and posterior parietal theta power increased and beta power decreased at faster walking speeds. We also found that left posterior parietal, mid cingulate, and cuneus exhibited differences in theta power at faster speeds between younger and older adults. The results suggest that older and younger adults activate cortical areas throughout the brain while walking at different speeds and older adults, particularly those with lower mobility, recruit greater cognitive resources in parietal cortex compared to younger adults. These results could inform stimulation protocols targeting parietal cortex.NEW & NOTEWORTHY Older and younger adults show widespread EEG beta power decreases at faster walking speeds compared to slower walking speeds. Older adults differentially alter EEG theta power while walking compared to younger adults. Prior studies with functional near-infrared spectroscopy (fNIRS) have documented differences in prefrontal activation in older adults walking compared to younger adults, but our results show cortical changes within speed and age outside of the prefrontal cortex.