Effect of treadmill walking on prefrontal cortex activation and dual-task performance in older adults

Background: Older adults have higher prefrontal cortex (PFC) activation and lower dual-task performance than younger adults because of age-related physical and cognitive functional impairments. Objective To investigate the effect of treadmill walking on PFC activation and dual-task performance in older adults. Methods A total of 20 older adults (mean age, 64.35 ± 2.74 years) and 20 younger adults (mean age, 30.00 ± 3.15 years) performed single- and dual-task walking in overground and treadmill conditions. A wearable functional near-infrared spectroscopy device and gait analyzer were used to analyze PFC activation and dual-task cost (DTC). Results In both groups, treadmill walking demonstrated reduced PFC activation while dual-task walking and reduced DTC compared to overground walking. Furthermore, despite a higher DTC in gait variability, correct response, total response, response index and a higher error score in older adults than in younger adults during overground walking, there was no difference in treadmill walking. The difference in PFC activation between single and dual tasks was also observed only in overground walking. There was no difference in PFC activation between the two age groups. Conclusions Older adults can maintain the similar level of dual-task performance as younger adults in treadmill walking, with PFC activation reduced. However, although older adults recruit PFC level similar to that in younger adults in overground walking, older adults show lower dual-task performance than younger adults due to inefficient use of PFC with aging. This indicates that treadmill and overground walking do not share similar activation patterns during dual-task walking.