脑组织氧合振荡与血压脉动的多频段相位耦合特性分析

Abnormal blood pressure has an important impact on the brain, such as hypertension is the most important risk factor for stroke, but also an important cause of cognitive decline and dementia. The interaction of cerebral vessels with neurons and glial cells constitutes a functional unit of neurovascular coupling. Brain tissue oxygen oscillations reflect the neural activity of the brain. Phase coupling is an effective method to measure the interaction between system oscillations. Measurement of brain tissue oxygenation by near -infrared spectroscopy (NIRS) is a mobile and portable technique for evaluating dynamic brain function. In this project the multi-channel brain tissue oxygenation signal and arterial blood pressure will be simultaneous measured and time series analysis of phase information between them will be extracted by wavelet analysis. Then coupling function between the blood pressure and brain tissue oxygen phase oscillation will be established based on dynamic Bayesian inference to analyze the interaction of blood pressure and brain tissue oxygen oscillation. Therefore, the effects of abnormal blood pressure on brain function can be investigated. Finally, combined with diffusion tensor imaging and functional magnetic resonance, the phase coupling model will be validated. The test subjects include healthy elderly, patients with hypertension and patients with cognitive disorder. The interaction is helpful to understand the development of brain dysfunction in hypertensives, and provide scientific evaluation for brain dysfunction at early risk; in turn, the research results will help develop a more reasonable rehabilitation measure method.

高血压是脑卒中最重要的危险因素，也是认知衰退和痴呆的重要原因。动脉血压脉动通过脑血管血流调节传递到大脑皮层，引发脑组织氧合振荡的变化。脑组织氧合振荡变化反映大脑皮层自发或诱发的神经性、代谢性等活动。近红外光谱法测量脑组织氧合参数是目前正快速发展的移动便携的脑功能评估技术。该项目提出通过同步测量多通道脑组织氧合和动脉血压信号，利用小波分析法提取脑氧振荡与血压脉动相位时间序列信息，建立二者相位耦合函数；然后，基于动态贝叶斯推理，估计二者耦合强度与传递方向系数，以此分析脑组织氧合振荡与血压脉动的相互作用，研究血压异常对脑功能的影响；最后，结合弥散张量成像和功能性磁共振成像等技术，测试分析高血压患者以及轻度脑认知障碍患者脑结构及功能连接特性，验证相位耦合模型的有效性。该课题的开展，有助于揭示血压脉动和大脑皮层神经血管耦合的相互作用机制，为脑功能障碍早期风险评估及康复训练提供科学的评价手段。

本项目总体研究目标为建立血压-脑氧振荡的相位耦合模型，分析风险因素对血压-脑氧振荡耦合的影响，揭示血压脉动与脑氧振荡的相互作用机制，为脑功能障碍早期风险评估及康复训练提供科学的评价手段。针对这一目标，该项目采用基于相位耦合函数的方法来研究功能性的大脑和血压之间的相互作用，确定因果联系及其相互作用机制。首先，通过优化数据处理方法，提取出更加纯净的脑血氧信号，应用动态贝叶斯推论，建立血压-脑氧振荡多频段相位耦合模型，研究血压脉动与脑氧振荡的相互作用机制；然后，应用血压-脑氧振荡多频段相位耦合模型，分析了高血压这一风险因素对血压-脑氧耦合的影响，发现高血压患者血压与脑氧振荡之间存在更强的耦合关系，表明高血压患者脑氧变化更易受到血压变化的影响。研究结果可作为高血压患者脑血流自主调节（CA）功能受损的证据。其次，研究了风险因素姿势性变化和年龄对血压-脑氧振荡多频段相位耦合，揭示老年人姿势性变化对脑功能的影响；再次，应用血压-脑氧振荡多频段相位耦合模型，研究了脑认知障碍患者血压-脑氧相位的耦合特性，同时结合功能性磁共振成像等技术，测试分析了高血压患者及轻度脑认知障碍患者功能连接特性，验证了基于近红外光谱的相位耦合模型评估脑功能障碍风险的有效性；最后，应用多频段血压-脑氧振荡相位耦合模型，研究了临床干预治疗（针灸、气动压力干预）对血压-脑氧耦合的影响及疗效。通过分析高血压患者在针灸治疗以及脑卒中患者在气动压力干预过程中血压-脑氧振荡相位耦合的变化，分析了临床干预治疗的有效性，为患者康复干预提供科学的评价手段。