After a stroke, people commonly experience problems with balance and also feel very tired, or fatigued. These issues can affect their physical therapy. The reasons for this are complex and involve both physical movement difficulties and changes in how the brain works. A region at the front of the brain called the prefrontal cortex is involved in controlling movement, but not much is known about its activity during common balance exercises or how it connects to fatigue after a stroke.

This study aimed to learn more about the prefrontal cortex's activity during standing balance tasks. Researchers wanted to know if brain activity levels changed with different tasks, if the activity was uneven between the brain's two sides, and if there was a link between brain activity and fatigue.

The study included nine people who had weakness on one side of their body due to a stroke. The researchers used a technique called functional near-infrared spectroscopy, which uses light to measure brain activity, placing it over both sides of the prefrontal cortex. Participants were measured while doing two balance tasks. Their fatigue was also measured using a questionnaire called the Fatigue Severity Scale.

The results showed that the prefrontal cortex was more active when participants stood in a more challenging position (with one foot partially in front of the other) than when they stood normally on two feet. This indicates the brain was working harder. Both sides of the prefrontal cortex were active during both balance tasks. Participants who reported greater fatigue also showed more brain activity on the side of the prefrontal cortex that was affected by the stroke compared to the unaffected side.

The study concludes that the prefrontal cortex may become more active when a person performs more difficult balance postures after a stroke. This could signal that the brain is working to make up for the injury. This increased brain activity may also be linked to higher levels of fatigue.