Neuroscience Research Australia, New South Wales, Australia; School of Population Health, Faculty of Medicine, University of New South Wales, New South Wales, Australia; School of Physiotherapy, Division of Health Sciences, University of Otago, Dunedin, New Zealand.
Neuroscience Research Australia, New South Wales, Australia; School of Population Health, Faculty of Medicine, University of New South Wales, New South Wales, Australia.
Gait Posture. 2022 Jan;91:247-253. doi: 10.1016/j.gaitpost.2021.10.038. Epub 2021 Oct 30.
People with Parkinson's disease (PD) have difficulties adapting their gait. While underlying neural mechanisms involving the prefrontal cortex (PFC) have been studied across various complex walking tasks, less is known about the premotor cortex (PMC) and supplementary motor area (SMA), key cortical regions for motor planning. This study compared frontal cortical regions activation patterns using functional near-infrared spectroscopy (fNIRS), between people with PD and healthy controls (HC) during gait adaptability tasks.
Forty-nine people with PD (mean (SD) age: 69.5 (7.9) years) and 21 HC (69.0 (5.9) years) completed a simple walk and three randomly presented gait adaptability tasks: (i) stepping on targets, (ii) avoiding obstacles and (iii) negotiating both targets and obstacles. Cortical activity in the dorsolateral PFC (DLPFC), SMA and PMC were recorded using fNIRS. Step length, velocity and accuracy and cortical activity were contrasted between the groups and walking conditions.
Compared with the HC, the PD group exhibited greater PMC activation and walked significantly slower and took shorter steps in all conditions. A statistically significant group by condition interaction indicated an increase in DLPFC cortical activation in the HC participants when undertaking the obstacle avoidance task compared with the simple walk but no increase in cortical activation in the PD group when undergoing this more challenging gait task.
Our findings suggest people with PD have little or no DLPFC, SMA and PMC capacity beyond what they need for simple walking and in consequence need to slow their gait velocity to meet the demands of target stepping and obstacle avoidance tasks. Such behavioral and neural patterns appear consistent with concepts of compensatory over-activation and capacity limitation.
帕金森病（PD）患者在行走时存在困难。尽管涉及前额叶皮层（PFC）的潜在神经机制已经在各种复杂的行走任务中进行了研究，但对于运动规划的关键皮质区域——运动前皮层（PMC）和辅助运动区（SMA），人们知之甚少。本研究使用功能近红外光谱（fNIRS）比较了 PD 患者和健康对照组（HC）在行走适应性任务中前额皮质区域的激活模式。
49 名 PD 患者（平均（SD）年龄：69.5（7.9）岁）和 21 名 HC（69.0（5.9）岁）完成了简单行走和三个随机呈现的行走适应性任务：（i）踏准目标，（ii）避开障碍物和（iii）同时避开目标和障碍物。使用 fNIRS 记录背外侧前额叶皮层（DLPFC）、SMA 和 PMC 的皮质活动。对比组间和行走条件下的步长、速度和准确性以及皮质活动。
与 HC 相比，PD 组在所有条件下 PMC 的激活程度更高，行走速度更慢，步幅更短。组间条件交互作用的统计显著表明，与简单行走相比，HC 参与者在进行障碍物回避任务时 DLPFC 皮质激活增加，但 PD 组在进行更具挑战性的行走任务时皮质激活没有增加。
我们的研究结果表明，PD 患者在简单行走以外的 DLPFC、SMA 和 PMC 能力很少或没有，因此需要降低行走速度以满足踏准目标和回避障碍物任务的要求。这种行为和神经模式似乎与代偿过度激活和能力限制的概念一致。
