Abstract
Increasing cerebral oxygenation, more precisely the overactivation of the prefrontal cortex (PFC), reflects cortical control of gait in stroke disease. Studies about the relationship between brain activation and the functional status in stroke patients remain scarce. The aim of this study was to compare brain activation, gait parameters, and cognitive performances in single and dual tasks according to the functional status in subacute stroke patients. Twenty-one subacute stroke patients were divided in two groups according to Barthel Index (“low Barthel” and “high Barthel”) and randomly performed ordered walking, cognitive task (n-back task), and dual tasks (walking + n-back task). We assessed gait performances (speed, variability) using an electronic walkway system and cerebral oxygenation (ΔO2Hb) by functional near-infrared spectroscopy. Patients with better functional status (high Barthel) showed a lower PFC activation (ΔO2Hb) and better gait parameters in single and dual tasks compared to low-Barthel patients, who exhibited decreased gait performances despite a higher PFC activation, especially in the unaffected side (P < 0.001). PFC overactivation in less functional subacute stroke patients may be due to the loss of stepping automaticity. Our results underline the interest of proposing rehabilitation programs focused on walking, especially for patients with low functional capacity.
Highlights
Stroke is associated with gait disorders, mainly characterized by a decreased gait speed [1] and a greater variability [2]
lower BI between and 90 (LoB) patients exhibited a higher activation than higher BI between and 100 (HiB) in STmot for O2Hb (3.13 ± 1.67 vs. 1.48 ± 1.67 μmol L−1, P = 0.025, Figure 1A) and for O2Hb-unaffected (1.70 ± 0.85 vs. 0.63 ± 0.92 μmol L−1, P = 0.011, Figure 1B) and in dual task (DT) for
Speed was higher, and gait variability was lower in HiB patients than in LoB in STmot (P = 0.0017 and P = 0.0016, respectively) and in DT (P = 0.0018 and P = 0.0013, respectively) (Table 1)
Summary
Stroke is associated with gait disorders, mainly characterized by a decreased gait speed [1] and a greater variability [2]. Walking is further affected by challenging conditions such as simultaneous cognitive and motor tasks [e.g., dual task (DT)] [3]. In stroke patients, this increased cognitive demand of walking during DT was underlined by the key role of the prefrontal cortex (PFC) [4], whose activation can be assessed by functional near-infrared spectroscopy (fNIRS) [5]. Studies using fNIRS reported a greater brain activity in the PFC during DT than in single task (ST) in Stroke, Functional Status, and Cerebral Oxygenation.
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