Holtzer Roee, Schoen Chelsea, Demetriou Eleni, Mahoney Jeannette R, Izzetoglu Meltem, Wang Cuiling, Verghese Joe
Department of Neurology, 1225 Morris Park Avenue, Van Etten, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
Ferkauf Graduate School of Psychology of Yeshiva University, Bronx, NY, USA.
Eur J Neurosci. 2017 Mar;45(5):660-670. doi: 10.1111/ejn.13518. Epub 2017 Jan 19.
The ability to walk is critical for functional independence and wellbeing. The pre-frontal cortex (PFC) plays a key role in cognitive control of locomotion, notably under attention-demanding conditions. Factors that influence brain responses to cognitive demands of locomotion, however, are poorly understood. Herein, we evaluated the individual and combined effects of gender and perceived stress on stride velocity and PFC Oxygenated Hemoglobin (HbO ) assessed during single and dual-task walking conditions. The experimental paradigm included Normal Walk (NW); Cognitive Interference (Alpha); and Walk-While-Talk (WWT) tasks. An instrumented walkway was used to assess stride velocity in NW and WWT conditions. Functional Near-Infrared-Spectroscopy (fNIRS) was used to quantify PFC HbO levels during NW, Alpha and WWT. Perceived task-related stress was evaluated with a single 11-point scale item. Participants were community residing older adults (age = 76.8 ± 6.7 years; %female = 56). Results revealed that higher perceived stress was associated with greater decline in stride velocity from single to dual-task conditions among men. Three-way interactions revealed that gender moderated the effect of perceived stress on changes in HbO levels comparing WWT to NW and Alpha. Attenuation in the increase in HbO levels, in high compared to low perceived stress levels, from the two single task conditions to WWT was observed only in men. Thus, older men may be more vulnerable to the effect of perceived stress on the change in PFC oxygenation levels across walking conditions that vary in terms of cognitive demands. These findings confer important implications for assessment and treatment of individuals at risk of mobility impairments.
行走能力对于功能独立性和健康至关重要。前额叶皮质（PFC）在运动的认知控制中起着关键作用，尤其是在需要注意力的情况下。然而，影响大脑对运动认知需求反应的因素却知之甚少。在此，我们评估了性别和感知压力对单任务和双任务行走条件下评估的步幅速度和PFC氧合血红蛋白（HbO）的个体及综合影响。实验范式包括正常行走（NW）；认知干扰（Alpha）；以及边走边说（WWT）任务。使用仪器化的人行道在NW和WWT条件下评估步幅速度。功能近红外光谱（fNIRS）用于量化NW、Alpha和WWT期间PFC HbO水平。使用一个11点量表项目评估与任务相关的感知压力。参与者为居住在社区的老年人（年龄 = 76.8 ± 6.7岁；女性占56%）。结果显示，在男性中，较高的感知压力与从单任务到双任务条件下步幅速度的更大下降相关。三因素交互作用表明，在比较WWT与NW和Alpha时，性别调节了感知压力对HbO水平变化的影响。仅在男性中观察到，与低感知压力水平相比，高感知压力水平下从两个单任务条件到WWT时HbO水平增加的衰减。因此，在不同认知需求的行走条件下，老年男性可能更容易受到感知压力对PFC氧合水平变化的影响。这些发现对评估和治疗有行动障碍风险的个体具有重要意义。
