Prefrontal cortex activation during a dual task in patients with stroke.

Dual tasks destabilize task performance as they involve competing demands for cognitive and physical resources. Several studies have reported that dual-task walking activates the prefrontal cortex (PFC), and recent studies have indicated a relationship between PFC and dual-task deterioration in healthy subjects. However, PFC activity during dual-task walking in stroke patients remains unclear. We investigated the association between PFC activity and dual-task interference on physical and cognitive performance in stroke patients. This study included 14 stroke patients and 14 healthy subjects who performed a calculation task while walking at a comfortable pace on the floor. PFC activity was assessed using wearable near-infrared spectroscopy. The calculation task and trunk linear accelerations were evaluated as measures of cognitive and physical performance. The dual-task deterioration on both physical and cognitive performance of stroke patients was significantly higher than in healthy subjects. PFC activation during dual-task walking was significantly lower in stroke patients. Although right PFC activation was negatively correlated with dual-task deterioration on physical performance in stroke patients, left PFC activation was negatively correlated with the dual-task cost on cognitive performance in healthy subjects. Thus, during dual-task walking, PFC activation might prioritize physical demands in stroke patients, but might prioritize cognitive demands in healthy subjects.