Abstract
Human cognitive-motor performance largely depends on how brain resources are allocated during simultaneous tasks. Nonetheless, little is known regarding the age-related changes in electrocortical activity when dual-task during walking presents higher complexity levels. Thus, the aim of this study was to investigate whether there are distinct changes in walking performance and electrocortical activation between young and older adults performing simple and complex upper limb response time tasks. Physically active young (23 ± 3 years, n = 21) and older adults (69 ± 5 years, n = 19) were asked to respond as fast as possible to a single stimuli or a double stimuli appearing on a touch screen during standing and walking. Response time, step frequency, step frequency variability and electroencephalographic (EEG) N200 and P300 amplitudes and latencies from frontal central and parietal brain regions were recorded. The results demonstrated that older adults were 23% slower to respond to double stimuli, whereas younger adults were only 12% slower (p < 0.01). The longer response time for older adults was accompanied by greater step frequency variability following double-stimuli presentations (p < 0.01). Older adults presented reduced N200 and P300 amplitudes compared to younger participants across all conditions (p < 0.001), with no effects of posture (standing vs walking) on both groups (p > 0.05). More importantly, the P300 amplitude was significantly reduced for older adults when responding to double stimuli regardless of standing or walking tasks (p < 0.05), with no changes in younger participants. Therefore, physically active older adults can attenuate potential walking deficits experienced during dual-task walking in simple cognitive tasks. However, cognitive tasks involving decision making influence electrocortical activation due to reduced cognitive resources to cope with the task demands.
Highlights
The combination of cognitive and motor tasks reduces the performance of at least one of the two tasks regardless of age, as it is related to the allocation of resources during simultaneous tasks (Malcolm et al, 2015; Vasquez et al, 2016)
There was a stimulus x group interaction [F(1, 38) = 38.00, p < 0.0001, ηp2 = 0.826, Figure 2], demonstrating that double stimuli from older adults was ∼23% slower when compared to single stimuli from older adults (p = 0.0001), as well as compared to single stimuli (∼40%, p = 0.00001) and double stimuli for young adults (∼31% p = 0.0001)
When the response time was analyzed for each group separately, it was found that the response time during double stimuli was longer when compared to single stimuli for young adults [F(1, 20) = 58.85, p < 0.0001, ηp2 = 0.746]
Summary
The combination of cognitive and motor tasks reduces the performance of at least one of the two tasks regardless of age, as it is related to the allocation of resources during simultaneous tasks (Malcolm et al, 2015; Vasquez et al, 2016). Such conditions can lead to reduced cognitive processing efficiency, reducing motor performance and the ability to react to unexpected events (Bayot et al, 2018; Gentili et al, 2018) This may be problematic for older adults during daily life situations that require walk and concurrent demanding cognitive tasks (Lindenberger et al, 2000). Despite physically active older adults can perform normal walking and simple precision stepping to young adults, they became slower than young adults when the complexity of the precision stepping task increased (Oliveira et al, 2018b) Such results suggest that even older adults that have an active physical lifestyle— an important factor to attenuate natural age-related decay in motor and cognitive performance—experience a greater decline in the performance of complex dual-tasks than young adults (Plummer et al, 2015). Little is known regarding the age-related changes in electrocortical activity when dual-task during walking presents different complexity levels
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
