The Acute Effects of Aerobic Exercise on Cognitive Control among People with Chronic Stroke

Background: Over half of stroke survivors have cognitive impairment, which impedes rehabilitation and functional recovery. Evidence suggests a single session of aerobic exercise improves cognitive functions among healthy adults. Whether this holds true for stroke survivors is unclear. The objective of this study was to examine whether one session of moderate-intensity aerobic exercise improves the cognitive control and attention of stroke survivors. Methods: Nine people with chronic stroke (>= 6 months poststroke) performed a modified Eriksen Flanker task with concurrent electroencephalography (EEG) before and immediately, 20 minutes, and 40 minutes after 20 minutes of moderate-intensity exercise and after 20 minutes of rest. The sessions were in randomized order. Accuracy and response time were recorded for congruent and incongruent stimuli. Differences in accuracy, response time, and event-related potentials (P300, reflective of decision making) were analyzed using repeated measures analysis of variance. Results: Improvements in EEG measures were noted after exercise. P300 amplitude at Fz was greater 40 minutes after exercise compared with after rest (P = .007). P300 latency was also shorter at 20 minutes after exercise compared with after rest for both congruent (465.8 milliseconds versus 500.0 milliseconds; P = .02) and incongruent (468.0 milliseconds versus 532.0 milliseconds; P = .003) conditions at the central electrode on the lesional side. Differences in behavioral performance after exercise were not significant. Conclusions: Preliminary results suggest that aerobic exercise improves cortical processes underlying cognitive control and attention 20-40 minutes postexercise. Future research should confirm results in a larger sample and examine whether attention-demanding rehabilitation in this window has improved outcomes.