Emory University, Atlanta, GA, USA.
Georgia Institute of Technology, Atlanta, GA, USA.
J Alzheimers Dis. 2018;63(2):645-654. doi: 10.3233/JAD-180036.
Mental stress has been linked to various chronic diseases including Alzheimer's disease, but the mechanisms underlying cognitive decline with mental stress are unknown. Reduced cardiovascular response to stress is associated with cardiovascular disease, and the latter is associated with cognitive impairment. We measured electrodermal activity, blood pressure, and cardiac hemodynamics in cognitively normal and mild cognitive impairment (MCI) adults (n = 76, mean age = 58 years, 46% MCI) during rest, a math test, and face-name recall tasks to derive the following cardiovascular indicators: mean arterial pressure, heart rate, stroke volume and cardiac output. These indicators were compared between the two groups. Cerebral blood perfusion via arterial spin-labeling MRI was measured in a subgroup who underwent an MRI scan (n = 30). Following exposure to mental stress, a decrease in stroke volume (p = 0.024) and cardiac output (p = 0.005) was found in the MCI group, but an increase in both parameters in the cognitively normal group. This difference was largest during face-name recall (standardized difference in stroke volume = -0.50, p = 0.029, and in cardiac output = -0.52, p = 0.023). Cardiac output during mental stress, but not at rest, decreased with cerebral perfusion (normal: p = 0.078, β= 1.97, R2 = 0.090; MCI: p = 0.007, β= 2.02, R2 = 0.008). No significant difference was found between the two groups at rest. This preliminary study suggests that individuals with MCI have an insufficient cardiac output, and in turn lower cerebral perfusion in response to mental stress.
精神压力与包括阿尔茨海默病在内的各种慢性疾病有关，但精神压力导致认知能力下降的机制尚不清楚。心血管对压力的反应降低与心血管疾病有关，后者与认知障碍有关。我们在认知正常和轻度认知障碍（MCI）成年人（n=76，平均年龄 58 岁，46%为 MCI）中测量了皮肤电活动、血压和心脏血流动力学，以得出以下心血管指标：平均动脉压、心率、每搏输出量和心输出量。在两组之间比较了这些指标。在进行 MRI 扫描的亚组中（n=30），通过动脉自旋标记 MRI 测量了脑血流灌注。在 MCI 组中，在精神压力后发现每搏输出量（p=0.024）和心输出量（p=0.005）下降，但在认知正常组中这两个参数均增加。在面孔名称回忆期间，这种差异最大（标准化每搏输出量差异=-0.50，p=0.029，心输出量差异=-0.52，p=0.023）。在精神压力下，而不是在休息时，心输出量随着脑灌注而降低（正常：p=0.078，β=1.97，R2=0.090；MCI：p=0.007，β=2.02，R2=0.008）。在休息时，两组之间没有发现显著差异。这项初步研究表明，MCI 个体在精神压力下，心输出量不足，进而脑灌注降低。
