Department of Biomedical Engineering & Biomedical Simulations Resource, University of Southern California, United States.
Department of Biomedical Engineering & Biomedical Simulations Resource, University of Southern California, United States.
Med Eng Phys. 2014 May;36(5):628-37. doi: 10.1016/j.medengphy.2014.02.025. Epub 2014 Mar 31.
In our previous studies, we have introduced model-based "functional biomarkers" or "physiomarkers" of cerebral hemodynamics that hold promise for improved diagnosis of early-stage Alzheimer's disease (AD). The advocated methodology utilizes subject-specific data-based dynamic nonlinear models of cerebral hemodynamics to compute indices (serving as possible diagnostic physiomarkers) that quantify the state of cerebral blood flow autoregulation to pressure-changes (CFAP) and cerebral CO2 vasomotor reactivity (CVMR) in each subject. The model is estimated from beat-to-beat measurements of mean arterial blood pressure, mean cerebral blood flow velocity and end-tidal CO2, which can be made reliably and non-invasively under resting conditions. In a previous study, it was found that a CVMR index quantifying the impairment in CO2 vasomotor reactivity correlates with clinical indications of early AD, offering the prospect of a potentially useful diagnostic tool. In this paper, we explore the use of the same model-based indices for patients with amnestic Mild Cognitive Impairment (MCI), a preclinical stage of AD, relative to a control subjects and clinical cognitive assessments. It was found that the model-based CVMR values were lower for MCI patients relative to the control subjects.
在我们之前的研究中，我们引入了基于模型的“功能性生物标志物”或“生理标志物”，它们有望改善早期阿尔茨海默病（AD）的诊断。所倡导的方法利用基于个体特定数据的大脑血液动力学动态非线性模型来计算指数（作为可能的诊断生理标志物），这些指数量化了每个个体的脑血流自动调节到压力变化（CFAP）和脑 CO2 血管舒缩反应性（CVMR）的状态。该模型是根据平均动脉血压、平均脑血流速度和呼气末 CO2 的逐拍测量值进行估计的，这些测量值可以在休息条件下可靠且无创地进行。在之前的一项研究中，发现量化 CO2 血管舒缩反应受损的 CVMR 指数与早期 AD 的临床指征相关，为潜在有用的诊断工具提供了前景。在本文中，我们探索了使用相同的基于模型的指数来评估遗忘型轻度认知障碍（MCI）患者，MCI 是 AD 的临床前阶段，与对照组和临床认知评估相对比。结果发现，与对照组相比，MCI 患者的基于模型的 CVMR 值较低。
