用于帕金森病脑功能状态检测的特征提取

发布时间：2018-02-28 09:27

本文关键词： 帕金森病脑功能状态相关分析因果分析双谱分析　出处：《中国科学院研究生院(长春光学精密机械与物理研究所)》2014年硕士论文　论文类型：学位论文

【摘要】：深部脑刺激（Deep Brain Stimulatin, DBS）技术是抑制和缓解帕金森病（Parkinson's Disease, PD）运动相关症状的有效手段，已经成为晚期帕金森病常用的治疗方式。目前，DBS技术一般指的是向特定大脑神经核团施加一定频率、幅度等参数的电脉冲刺激序列，调整基底神经节网络的过度同步化现象，有效改善帕金森静止性震颤等运动功能。现在应用中DBS的刺激方式为持续的电脉冲刺激序列，刺激效率较低，，并有较明显的副作用。正处于研究中的闭环DBS技术，试图识别、区分与帕金森病相关的不同脑功能状态，并在脑功能状态处于异常状态时施加准确剂量的电刺激，有效提升DBS临床刺激效率，节省刺激器功耗，改善治疗效果，已成为DBS技术的发展方向。本文从帕金森患者丘脑底核区域的局部场电位信号（Local Field Potential,LFP）入手，研究大脑信号与帕金森病相关脑功能状态的关系，寻找合适的方法量化LFP信号与脑功能状态的映射关系，为闭环DBS控制系统反馈环节做了理论方面的工作。首先，采集和筛选帕金森病静止性震颤相关的肌电信号(Electromyography,EMG)和局部场电位信号，研究与静止性震颤相关的神经活动在频域上能量分布的基本特征。采用功率谱分析方法，确定了与震颤相关的神经活动主要分布在0-40Hz频段内，并且Delta（0-4Hz）、Theta（4-8Hz）、Alpha（8-12Hz）和Beta（12-30Hz）四个子频段占据了绝大部分能量。其次，针对3-30Hz频段场电位信号，采用时频分析手段考察该频段内不同频率成分随时间变化的动态特征，将与疾病状态相关的神经活动范围缩小为3-20Hz。短时傅里叶变换分析3-20Hz震颤状态的场电位信号，发现Delta、Theta、Alpha和低Beta频段内存在具有同步变化规律的多个频率成分，并且各个成分的中心频率之间成倍数关系；静息状态不具备明显的同步现象。再次，研究震颤状态3-20Hz多个倍频成分保持同步变化规律的内在机制，分析震颤状态下保持同步变化的多个倍频成分幅度之间的线性耦合关系。采用基于Hilbert变换的跨频率相关分析研究多倍频成分两两之间的互相关关系，揭示了多个倍频成分在震颤状态的统计相关性明显高于静息状态。对多倍频成分的时域Granger因果分析显示，震颤状态下Delta对Theta、Delta对Alpha、Theta对Alpha、Alpha对低Beta的产生有更强的因果驱动关系，一定程度上解释了相关分析中的统计相关性。最后，研究3-20Hz频段多倍频成分的非线性耦合关系，采用高阶统计量手段检测出多倍频成分间二次相位耦合作用的存在，根据震颤和静息状态具有的二次相位耦合作用的不同分布和耦合强度等特征可区分震颤状态和静息状态对应的丘脑底核功能状态。本文从复杂的神经活动中逐渐确定了与帕金森病震颤症状的神经波动成分，研究这些神经波动成分间线性耦合和非线性耦合的交互作用，基本实现了对帕金森病震颤和静息两个状态的丘脑底核区域神经活动分类。本文关于帕金森病静止性震颤脑功能状态检测的工作有助于闭环深部脑刺激技术的发展。
[Abstract]:Deep brain stimulation ( DBS ) is an effective means of inhibiting and relieving the symptoms associated with Parkinson ' s disease ( PD ) . This paper starts with the local field potential ( LFP ) of the thalamosal nucleus region of Parkinson ' s disease , and studies the relationship between brain signals and brain functional states of Parkinson ' s disease , and looks for a suitable method to quantify the mapping relationship between LFP signal and brain functional state , which provides theoretical work for the feedback link of the closed - loop DBS control system . First , EMG and local field potential signals related to Parkinson ' s disease were collected and screened . The basic features of energy distribution in the frequency domain were studied by means of power spectrum analysis . The main distribution of nerve activity related to tremor was determined in the range of 0 - 40 Hz , and the four sub - bands of Delta ( 0 - 4Hz ) , Theta ( 4 - 8Hz ) , Alpha ( 8 - 12Hz ) and Beta ( 12 - 30Hz ) occupied most of the energy . Secondly , a time - frequency analysis method is used to study the dynamic characteristics of different frequency components in the frequency band with time variation for the 3 - 30Hz band field potential signal , and the range of neural activity related to the disease state is reduced to 3 - 20Hz . The short - time Fourier transform analysis analyzes the field potential signal with the state of 3 - 20Hz . It is found that there are multiple frequency components with synchronous change law in the delta , Theta , Alpha and low Beta bands , and the center frequency of each component is multiple ; the resting state does not have obvious synchronization phenomenon . In this paper , the correlation between multiple frequency doubling components in the state of tremor is studied , and the correlation between the amplitudes of multiple frequency doubling components in the state of tremor is analyzed . The correlation between the amplitude of multiple frequency components in the state of tremor is analyzed . The results show that the statistical correlation between the multiple frequency components in the state of tremor is higher than that of rest . Finally , the nonlinear coupling relationship of multi - frequency components in the 3 - 20Hz frequency band is studied , and the existence of the secondary phase coupling between the multi - frequency components is detected by means of high - order statistics , and the state of the functional states of the thalamus and the nucleus of the thalamus corresponding to the resting state can be distinguished according to the characteristics such as the different distribution and coupling strength of the secondary phase coupling effect of the tremor and the resting state . In this paper , the nerve fluctuation component of Parkinson ' s disease is gradually determined from complex nerve activity , and the interaction of linear coupling and non - linear coupling between these nerve wave components is studied , and the neuroactive classification of the thalamosal nucleus region of Parkinson ' s disease tremor and resting state is basically realized . The work of this paper is helpful to the development of the closed - loop deep brain stimulation technique .

【学位授予单位】：中国科学院研究生院(长春光学精密机械与物理研究所)
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R742.5

【共引文献】