应用脑功能成像技术研究脑卒中运动想象疗法神经康复机制

发布时间：2018-08-19 06:14

【摘要】：近年来,运动想象(motor imagery,MI)疗法已经快速发展成为一种用于脑卒中偏瘫患者运动功能康复的新疗法。研究证明具有明显的肢体运动的运动执行(motor execution,ME)和没有明显肢体运动,精神上对运动执行进行排演的运动想象,两者在运动系统的脑功能区具有重叠性,同时证实了运动想像对于卒中患者的运动功能康复起着重要的作用。随着现代科学的发展,脑功能成像技术应用越来越广泛。本文采用功能磁共振成像(functional magnetic resonance imaging,f MRI)、弥散张量成像(diffusion tensor imaging,DTI)、功能近红外光谱成像(functional Near-infrared spectroscopy,f NIRS)技术研究了脑卒中运动想象疗法神经康复机制。其主要内容及研究结果包括以下四个部分:①比较研究了f MRI、DTI、f NIRS三种成像技术的基本原理,提出了基于多种脑功能成像技术多角度多层面地对运动想象认知过程的神经机制进行研究。f MRI能够从神经元活动的角度了解脑运动功能区的激活及脑区间的信息整合。DTI像能够直观的显示脑功能区之间的纤维连接,监测脑白质微结构的变化。新技术f NIRS研究脑的皮层活动,可以与f MRI的结果相印证,对运动想象的脑功能进行更为精确的分析。②融合f MRI、DTI、f NIRS技术研究健康老年人和青年人运动执行和运动想象的脑神经元活动。研究结果发现:1)老年人运动执行时,双侧的运动前区(premotor cortex,PMC),初级运动区(primary motor cortex,M1),辅助运动区(supp motor area,SMA)的激活明显比青年人更强更大,运动想象激活运动皮层随着年龄增大越来越困难。2)右手运动执行的有效连接网络,老年人连接强度大于青年人,且均为右侧脑区流向左侧脑区。3)运动想象有效连接网络,老年人的有效连接强于青年人,且有显著性差异的有效连接都位于对侧脑区。4)结构连接网络中老年人涉及运动、认知的脑组织结构及结构环路连接强度呈现下降的趋势。这些研究结果提示我们随着年龄增大,同侧脑区的抑制作用在减少,老年人为了完成同等水平的执行功能,需要招募更多的同侧脑区参与活动,因此在有效连接网络中,老年人的连接强度更强,连接条数更多。随着年龄增大,运动想象越来越困难,因此需要更多更强的信息交换才能激活运动皮层。结构网络中涉及运动皮层的连接降低,从一定程度上解释了老年人运动功能退化的原因。利用f NIRS研究了青年人运动执行和运动想象的脑功能区神经元的活动,与f MRI结果相符,为脑功能成像提供了一种新的研究方法。这些研究结果对于研究运动想象和脑老化的神经生理机制,对运动想象疗法和延缓老化等问题具有重要参考意义。③联合f MRI和DTI技术研究卒中患者运动系统脑功能异常的神经生理机制。研究结果发现:1)右手偏瘫患者患侧手运动执行时,对侧M1,PMC,SMA有显著激活,同侧脑区激活比较少,偏侧化明显;运动想象时双侧的M1,PMC,SMA具有很强的激活,偏侧化不明显。2)左手偏瘫患者患侧手运动执行时,运动皮层和非运动区域有明显激活;运动想象时运动区域激活比较少,非运动区域有明显激活。卒中患者的运动皮层网络具有一致性的结果:1)患侧手运动执行时,每个半球运动脑区之间有信息环路,但是半球脑区之间的有效连接很少。2)相较于对照组,偏瘫患者运动执行和运动想象的有效连接网络简单,连接强度弱,运动想象尤为严重。3)卒中患者的运动皮层之间,以及运动皮层和皮下核团结构连接明显降低。这些结果提示我们卒中患者患手侧为利手侧,运动想象脑功能区激活模式与健康人相似,激活运动功能区;患手侧为非利手侧时,非运动区域的激活可能与卒中患者的脑功能重塑有关。卒中患者由于脑部病变,涉及运动的脑组织结构连接强度明显降低,从而导致运动脑功能区激活困难,功能区之间的有效连接少,信息整合困难,不能很好的进行运动的控制和运动计划,从而造成了运动功能的障碍。总的来说,尽管卒中患者的运动控制,运动计划,运动执行等异常,但是运动想象可以提供一个有效的方式刺激卒中患者运动皮层的激活,活化原有的运动环路,促进运动功能的康复。④运动想象疗法临床应用研究。本文设计了与卒中患者日常康复训练内容一致的运动想象疗法指导语,对2例常规康复治疗、6例常规康复加运动想象疗法的右手偏瘫患者进行了纵向追踪,采集了治疗前,治疗4周后两次f MRI数据,同时进行了简化Fugl-Meyer(FMA)运动功能评定。研究结果发现经过一段时间的运动想象训练后,卒中患者通过运动想象更容易激活运动功能区,脑区激活模式明显优于早期,激活强度和激活的体素数更接近健康被试,并且功能康复的速度明显优于常规治疗患者。这一结果从功能影像方面研究了卒中患者康复过程中的运动皮层脑功能的动态变化,证明了运动想象疗法结合常规康复治疗,可以强化主动运动学习,促进患肢运动功能恢复,为临床运动想象疗法提供了理论依据。总的来说,本文利用多种脑功能成像技术,从脑功能定位(功能分离),脑功能网络(功能整合),脑结构网络(物质基础)融合分析研究了健康人的运动系统的脑功能神经机制。其次在基于健康人研究结果的基础上,继续对卒中患者的运动系统脑功能成像进行深入研究。最后根据影像学的研究结果,设计了卒中患者的运动想象疗法方案,进行了临床应用研究。本研究对运动想象疗法提供了影像学依据,并为运动想象疗法的效用情况、适应症选择提供了客观的观测指标,这对脑卒中的临床康复治疗具有十分重要的理论意义和实用价值。
[Abstract]:In recent years, motor imagery (MI) therapy has rapidly developed into a new therapy for motor function rehabilitation in stroke patients with hemiplegia. Studies have shown that there are obvious motor execution (ME) and mental rehearsal of motor execution without obvious physical movement. With the development of modern science, functional magnetic resonance imaging (f MRI) and diffusion tensor imaging (DTI) have been widely used in functional brain imaging. Diffusion tensor imaging (DTI) and functional near-infrared spectroscopy (f NIRS) techniques have been used to study the neural rehabilitation mechanism of motor imagery therapy for stroke. The main contents and results of the study include the following four parts: (1) The basic principles of three imaging techniques, namely, f MRI, DTI and f NIRS, have been compared and studied. Neural mechanisms of motor imagery cognitive processes are studied from multiple perspectives and layers based on various brain functional imaging techniques.f MRI can understand the activation of brain motor functional areas and information integration of brain regions from the perspective of neuronal activity.DTI can visually display the fiber connections between brain functional areas and monitor the changes of white matter microstructure. The new technique f NIRS can be used to study the cortical activity of the brain, which can be confirmed by the results of F MRI, and to analyze the brain function of motor imagery more accurately. The activation of premotor cortex (PMC), primary motor cortex (M1) and supp motor area (SMA) was stronger and stronger than that of young people. The activation of motor cortex by motor imagery became more and more difficult with age. 2) The effective connection network of right-handed motor execution was stronger in the elderly than in the young. 3) The effective connectivity of motor imagery was stronger in the elderly than in the young, and the effective connectivity with significant differences was located in the contralateral brain area. 4) The elderly involved in motor activity in the structural connectivity network, and the cognitive brain structure and the strength of structural loop connectivity showed a downward trend. The results suggest that the inhibition of ipsilateral brain area decreases with age. In order to perform the same level of executive function, the elderly need to recruit more ipsilateral brain areas to participate in activities. Therefore, in an effective connection network, the elderly have stronger connection strength and more connections. More and more information exchange is needed to activate the motor cortex. Decreased connectivity involving the motor cortex in the structural network may explain the deterioration of motor function in the elderly to some extent. Energy imaging provides a new method for studying the neurophysiological mechanism of motor imagery and brain aging, and has important reference value for motor imagery therapy and delaying aging. Now: 1) The contralateral M1, PMC and SMA were significantly activated in the right hand hemiplegic patients, while the ipsilateral brain area was less activated and hemiplegic was obvious; the bilateral M1, PMC and SMA were strongly activated in the motor imagery, but the hemiplegia was not obvious. The motor cortical network of stroke patients showed consistent results: 1) There were information loops between each hemispheric motor cortex, but there were few effective connections between the hemispheric motor cortex. 2) Compared with the control group, hemiplegic patients performed motor and motor activities. These results suggest that the active pattern of motor imagery brain area is similar to that of healthy people, activating motor work. The activation of non-motor areas may be related to the remodeling of brain function in stroke patients when the affected hand side is the disadvantaged hand side. Generally speaking, although there are abnormalities in motor control, motor planning and motor execution in stroke patients, motor imagery can provide an effective way to stimulate the activation of motor cortex, activate the original motor circuit and promote motor function. Rehabilitation. 4. Clinical application of motor imagery therapy. In this paper, we designed the instructions of motor imagery therapy which are consistent with the daily rehabilitation training of stroke patients. Simplified Fugl-Meyer (FMA) motor function assessment was performed. The results showed that after a period of exercise imagery training, stroke patients were more likely to activate motor function areas through motor imagery. The activation patterns of brain regions were significantly better than those in the early stage. The activation intensity and the number of active voxels were closer to the healthy subjects, and the speed of functional rehabilitation was obvious. The results showed that motor imagery therapy combined with routine rehabilitation therapy could strengthen active motor learning and promote the recovery of motor function of affected limbs, which provided a theoretical basis for clinical motor imagery therapy. Generally speaking, this paper uses a variety of brain functional imaging techniques to study the brain functional and neural mechanisms of the motor system in healthy people from the aspects of brain functional localization (functional separation), brain functional network (functional integration) and brain structural network (material basis). Finally, according to the results of the imaging study, a scheme of motor imagery therapy for stroke patients was designed and its clinical application was studied. This study provides the imaging basis for motor imagery therapy, and provides an objective observation index for the effectiveness of motor imagery therapy and the selection of indications. The clinical rehabilitation treatment of stroke is of great theoretical significance and practical value.
【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R743.3

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