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1.
轻度认知障碍患者视空间功能的fMRI研究   总被引:9,自引:0,他引:9  
目的 :探索早期诊断Alzheimer病的方法。 方法 :对轻度认知障碍 (MCI)患者和正常对照各 9名在fMRI下进行指针位置辨别的视空间功能测试。结果 :MCI患者比正常对照的反应时间延长 ,正确率降低 ,脑激活图显示MCI患者比正常对照在双侧顶叶 ,颞枕交界处和视觉皮层的激活强度显著减弱 (P <0 .0 5 ) ,范围减小 ,而在右侧额中回的激活代偿性增强。结论 :MCI患者视空间功能受损 ,这可通过fMRI来加以检测。  相似文献   

2.
目的 运用核磁共振(MRI)技术探讨轻度认知障碍(MCI)老人与健康老人脑结构和功能的异同.方法 对14例MCI老人(MCI组)和15名健康老人(正常对照组)进行神经心理学检查,并应用基于体素的形态测量方法 ,测定两组的灰质体积,并用事件相关功能MRI技术,测定两组在执行情节记忆提取任务时相关脑区的功能变化.结果 (1)神经心理学:MCI组听觉词语记忆测试[(2.1±1.7)分]和画钟试验[(7.8±1.2)分]成绩差于正常对照组[分别为(9.2±1.3)分和(9.2±0.8)分;P<0.05].(2)结构影像:MCI组的灰质体积小于正常对照组,主要位于情节记忆相关脑区(P<0.001).(3)功能影像:MCI组与正常对照组任务正确率和反应时间的差别无统计学意义;MCI组激活降低的脑区主要是海马旁回,而增强激活的脑区主要是前额叶前侧、背外侧、右侧颞上回、右侧颞下回、枕叶皮层(P<0.005).结论 MCI组内侧颞叶记忆系统结构萎缩、功能下降,在任务难度适当的情节记忆提取任务中,MCI组动员额外脑区激活,以代偿颞叶内侧记忆系统的损害.  相似文献   

3.
目的:探索早期诊断Alzheimer病的方法.方法:对轻度认知障碍(MCI)患者和正常对照各9名在fMRI下进行指针位置辨别的视空间功能测试.结果:MCI患者比正常对照的反应时间延长,正确率降低,脑激活图显示MCI患者比正常对照在双侧顶叶,颞枕交界处和视觉皮层的激活强度显著减弱(P<0.05),范围减小,而在右侧额中回的激活代偿性增强.结论:MCI患者视空间功能受损,这可通过fMRI来加以检测.  相似文献   

4.
颞叶癫痫患者磁共振弥散张量成像及记忆损害的研究   总被引:1,自引:0,他引:1  
目的利用磁共振弥散张量成像技术(DTI)研究颞叶癫痫(TLE)患者脑内微观改变及记忆损害的相关脑区。方法对颞叶癫痫患者15例和健康对照者15例,进行DTI检查,利用韦氏记忆量表检测记忆功能。结果 TLE患者部分各向异性弥散(FA)值降低激活区域有颞叶、边缘叶、扣带回和岛叶,升高区有:额叶、顶叶、枕叶,表观系数(ADC)值升高激活区域在颞叶、额叶、枕叶、顶叶;无ADC值降低区域。与健康者相比,颞叶癫痫患者的记忆商数(MQ)(90.73±19.72)显著下降,P<0.01。对照组FA值在左岛叶、颞叶与MQ值正相关;患者组FA值在右额、顶、枕叶、左顶叶与MQ值正相关,在左颞叶与MQ值负相关。对照组ADC与MQ正相关区域在左边缘叶,与MQ成负相关区域在左顶叶、患者组正相关区域在左、右颞叶。结论初步证实TLE患者的脑内结构变化不局限于颞叶,还包括颞叶外网络结构;TLE患者全脑DTI与MQ存在着相关激活脑区,表明记忆功能损害与脑内相关结构改变有关。  相似文献   

5.
目的 比较丙泊酚Wada试验与功能磁共振(fMRI)在左颞叶癫痫患者术前记忆功能偏侧化预测中的一致性和敏感性. 方法 对广州军区广州总医院自2009年10月至2011年10月收治的8例左前颞叶切除的癫痫患者术前进行丙泊酚Wada试验和fMRI记忆功能偏侧化评估,结合韦氏记忆测验结果,比较两者记忆功能偏侧化评估的一致性与预测记忆变化的敏感性. 结果 fMRI词汇记忆半球、内侧颞叶功能偏侧化与Wada试验功能偏侧化判定的一致率分别为57.0%和71.4%,术后记忆商数、词汇匹配以及智力改变与fMRI词汇记忆内侧颞叶功能偏侧化指数呈显著相关(r=-0.314,P=0.037;r=-0.387,P=.013;r=0.116,P=0.020),与Wada试验功能偏侧化指数无相关性(r=-0.442,P=.077;r=-0.241,P=0.237;r=-0.070,P=0.107). 结论 丙泊酚Wada试验和fMRI记忆功能偏侧化评估一致性因感兴趣区选择方法不同而不同.相对于Wada试验,fMRI记忆功能偏侧化指数在预测患者术后词汇记忆下降的过程中敏感性更高.  相似文献   

6.
目的研究轻度认知功能障碍(MCI)和血管性轻度认知功能障碍(VaMCI)患者各认知功能脑区域脑血流量(CBF)的特点,为早期诊断提供科学依据。方法选择2016年1月-2018年1月昆明市延安医院神经内科门诊及住院部确诊的24例MCI患者(MCI组)和24例VaMCI(VaMCI组)患者及24名老年健康志愿者(正常对照组)作为研究对象,运用动脉自旋标记(ASL)技术采集3组受试者认知功能脑区域的CBF数据。结果与正常对照组相比,MCI组双侧额叶、双侧海马脑血流灌注增加,双侧颞叶、楔前叶等部位脑血流灌注降低(P 0. 05);与正常对照组相比,VaMCI组双侧额叶、双侧海马脑血流灌注增加,双侧楔前叶、角回等部位脑血流灌注降低(P 0. 05);与MCI组相比,VaMCI组左侧颞叶、双侧扣带回、左侧杏仁核脑血流灌注增加,右侧颞叶、右侧扣带回等部位脑血流灌注降低(P 0. 05)。结论 MCI患者和VaMCI患者认知功能脑区域脑血流灌注具有不同的特点,磁共振ASL技术能够为两者的鉴别提供影像学帮助。  相似文献   

7.
目的考察轻度认知损害(mild cognitive impairment,MCI)和阿尔茨海默病(Alzheimer’s disease,AD)的大脑灰质体积是否存在异常及其与记忆功能的关系。方法本研究共纳入56例轻度AD、14例MCI和16例正常对照,所有被试均进行了记忆功能测查和磁共振影像检查。影像数据分析采用患者基于体素的脑形态学分析(voxel-based morphometry,VBM)。结果 AD组和MCI组记忆测验评分下降,呈AD组相似文献   

8.
目的通过磁共振弥散张量成像研究不同区域脑白质损害与轻度认知功能(MCI)的关系。方法纳入2015年7月至2016年2月我院的住院患者56例为研究对象,其中MCI组34例,认知功能正常组22例。所有研究对象进行一般情况检查,完成神经心理学量表检测。通过头颅磁共振弥散张量成像(DTI)检查对不同脑区白质纤维进行部分各向异性(FA)值测量。结果 MCI组患者与认知功能正常组相比,右侧额叶FA值(0.335±0.068)、左侧颞叶白质FA值(0.391±0.032)及胼胝体膝部FA值(0.658±0.053)降低,差异具有统计学意义(P0.05)。将上述FA值和MMSE、Mo CA量表中各认知域进行典型相关分析,结果显示右侧额叶白质FA值与注意与计算力呈正相关,左侧颞叶白质和胼胝体膝部FA值与记忆力呈正相关(P0.05)。结论 MCI患者注意与计算力的障碍可能与右侧额叶白质损害有关,而左侧颞叶白质及胼胝体膝部白质的损害可能导致早期的记忆障碍。DTI可能成为超早期识别与诊断MCI的新方法。  相似文献   

9.
颞叶癫痫患者警觉功能的脑功能磁共振研究   总被引:1,自引:0,他引:1  
目的利用注意网络测试(ANT)软件和功能核磁共振(fMRI)成像技术探讨颞叶癫痫(TLE)患者的警觉网络功能特点、激活模式及其脑功能状态。方法对12例TLE患者及匹配的8名健康志愿者进行研究。使用ANT软件进行警觉功能行为学测试,记录反应时间(RT);并采用ANT改良的警觉网络功能组块模式fMRI扫描,fMRI数据采用统计参数图(SPM2)软件分析。结果 TLE患者组与健康对照组ANT警觉网络功能的反应时间无差异。健康对照组警觉网络fMRI显示右枕叶、小脑明显激活;右边缘叶、右额叶及左侧颞叶、脑干部分激活。TLE患者组存在相同警觉网络相关脑区,但激活明显减弱且颞叶和脑干无激活。结论健康对照警觉网络功能与右侧枕叶、小脑、右额叶、脑干及颞叶等脑区相关。TLE患者存在警觉网络相关脑区功能明显低下,可能是TLE患者出现警觉功能损害的脑功能基础。  相似文献   

10.
目的 基于静息态功能磁共振(fMRI)图像数据,运用局部一致性(ReHo)方法研究精神分裂症幻听患者静息态脑区活动情况.方法 对18例精神分裂症幻听患者和18例与之相匹配的健康对照人群进行静息态fMRI研究,运用ReHo方法对静息态fMRI数据进行统计分析,并将其结果进行组内和组间分析.结果 组内分析结果显示,两组静息态下脑区BOLD信号的ReHo值升高大多位于大脑“默认网络区域”(额叶、颞叶、扣带回等);就激活脑区面积大小来说,病例组明显减少,即精神分裂症幻听患者静息态脑区活动整体而言是减弱的.组间分析结果显示,与健康对照组相比精神分裂症幻听患者静息状态右侧额叶BOLD信号ReHo值明显降低(P<0.001,纠正后cluster水平).结论 精神分裂症幻听患者颞叶功能活动增强且存在额叶活动异常,提示颞叶功能活动增强和额叶功能活动减弱可能是精神分裂症患者产生幻听的神经影像基础.  相似文献   

11.
OBJECTIVE: To define the neuropathologic findings in amnestic mild cognitive impairment (MCI) and early Alzheimer disease (EAD). METHODS: The mean numbers of diffuse plaques, neuritic plaques (NPs), and neurofibrillary tangles (NFTs) in 4 neocortical regions and 4 ventromedial temporal lobe regions were counted in 10 patients with amnestic MCI and compared with the mean numbers in 23 normal control subjects and 10 patients with EAD, and then were compared with memory performance. All of the controls and patients were followed longitudinally. RESULTS: Patients with MCI showed no significant difference (P>.05) in the number of diffuse plaques from that in normal controls or patients with EAD. In patients with MCI, the number of NPs was significantly elevated in all 4 neocortical regions and amygdala compared with controls (P<.01 to <.001). There were no significant differences (P>.05) in the number of NPs between MCI and EAD cerebral cortex, but significant increases were present for NPs in EAD amygdala and subiculum compared with MCI (P<.01). In patients with MCI compared with controls, the only significant increase in NFTs in the neocortex was in the parietal lobe. However, the number of NFTs was significantly elevated in MCI in all 4 ventromedial temporal lobe structures compared with controls (P<.01 to <.001). In comparing MCI with EAD, there were significant increases in NFTs in EAD in frontal and temporal lobes, amygdala, and subiculum (P<.01). The numbers of NPs and NFTs were significantly elevated in all of the neocortical regions and ventromedial temporal lobe regions in patients with EAD compared with controls (P<.001). Memory function was significantly correlated with NFTs in CA1 of the hippocampus (P<.01) and the entorhinal cortex (P<.05). CONCLUSIONS: In patients with amnestic MCI who were followed longitudinally, the early changes of Alzheimer disease were present. The NFTs were slightly more prominent than beta-amyloid peptide deposition in the progression from normal to MCI to EAD. Ventromedial temporal lobe NFTs probably represent the substrate for memory decline in MCI. From a neuropathologic perspective, it appears that amnestic MCI is, in reality, EAD.  相似文献   

12.
BACKGROUND: Large numbers of neurofibrillary tangles (NFTs) and amyloid plaques are diagnostic markers for Alzheimer disease (AD), but lesser numbers of these lesions are also seen in nondemented elderly individuals. Much of the existing literature suggests that the NFTs of AD have a closer correlation with cognitive function than do amyloid plaques. Whether a similar relationship exists in normal aging and mild cognitive impairment (MCI), a condition that frequently reflects a preclinical stage of AD, remains unknown. OBJECTIVE: To determine the distribution patterns of beta-amyloid plaques and NFTs and the association of these lesions with memory performance in nondemented individuals. METHODS: We investigated regional distributions and neuropsychological correlates of NFTs and amyloid plaques in cognitively normal elderly persons and subjects with MCI who received neuropsychological testing before death.Subjects Eight nondemented subjects who volunteered to receive annual neuropsychological testing and agreed to brain donation were studied. Five subjects showed no cognitive impairment, and 3 were diagnosed with MCI. RESULTS: Distribution of NFTs followed a rigorous and hierarchical pattern, but distribution of amyloid plaques varied among individuals. Subjects with MCI displayed higher NFT densities than did nonimpaired subjects. In addition, NFT density in the temporal lobe correlated with memory scores, whereas density of amyloid plaques did not. CONCLUSIONS: Neurofibrillary tangles are more numerous in medial temporal lobe regions associated with memory function and show a relationship to performance on memory tests in nondemented individuals. These results suggest that NFTs may constitute a pathological substrate for memory loss not only in AD but also in normal aging and MCI.  相似文献   

13.
Differential cortical atrophy in subgroups of mild cognitive impairment   总被引:7,自引:0,他引:7  
OBJECTIVE: To compare gray matter brain volumes in patients diagnosed with subtypes of mild cognitive impairment (MCI) (those with a focal amnestic disorder and those with more diffuse cognitive dysfunction) with those of elderly controls. DESIGN: Magnetic resonance imaging volumetric study of MCI subgroups (MCI-amnestic [MCI-A], and MCI-multiple cognitive domain [MCI-MCD]) using a whole brain voxel-based analysis. SETTING: Referral dementia clinic.Patients Thirty-seven patients with MCI (age range, 49-85 years; MCI-A, n = 9; MCI-MCD, n = 28) and 47 control subjects (age range, 55-81 years). MAIN OUTCOME MEASURES: Volumetric anatomical magnetic resonance imaging differences between MCI subgroups and normal controls, and between patients with MCI who progressed to dementia. Magnetic resonance imaging scans were analyzed using statistical software SPM99. RESULTS: Overall, the patients with MCI had significantly decreased volume in the hippocampus and middle temporal gyrus, bilaterally, compared with control subjects. Compared with patients with MCI-MCD, patients with MCI-A had significant volume loss of the left entorhinal cortex and inferior parietal lobe. Compared with patients with MCI-A, patients with MCI-MCD had significantly reduced volume of the right inferior frontal gyrus, right middle temporal gyrus, and bilateral superior temporal gyrus. Patients with MCI who progressed to Alzheimer disease during follow-up (mean interval 2 years, maximum 4.5 years), showed greater atrophy in the left entorhinal cortex, bilateral superior temporal gyri, and right inferior frontal gyrus compared with those who did not progress. CONCLUSIONS: These data provide evidence of distinct brain structural abnormalities in 2 groups of patients with MCI. While both have mesial temporal and cortical volume loss, those with a focal memory deficit have more involvement of the mesial temporal structures and less involvement of the neocortical heteromodal association areas than those patients with MCI with diffuse cognitive dysfunction. Thus, MCI may represent a more heterogeneous group than currently conceived, possibly reflecting 2 different etiological processes to dementia. These data also suggest that these structural abnormalities precede the development of Alzheimer disease.  相似文献   

14.
White matter (WM) integrity in the medial temporal lobes and episodic memory performance were examined in patients with mild cognitive impairment (MCI) and age-matched cognitively intact controls. Material specific associations between WM in the left versus right hemisphere and verbal versus visual memory performance were examined as well. Fourteen right-handed amnestic MCI patients underwent diffusion tensor imaging (DTI) and received verbal (words, story) and visual (designs) memory tests. Delayed verbal memory was significantly correlated with loss of WM integrity in the medial temporal lobe. This finding was associated with both the left and right temporal regions. Immediate visual memory performance was significantly correlated with the loss of WM integrity in the left temporal region. The results indicate that WM integrity in the medial temporal lobe is associated with objective memory functioning in MCI. However, strong material specific relationships were not observed, possibly reflecting diverse encoding strategies used by participants such as imagery of verbal material and verbal encoding of designs. This research was supported by a pilot grant from the Emory Alzheimer’s Disease Research Center (NIH-NIA 5 P50 AG025688).  相似文献   

15.
BACKGROUND: Neuroimaging studies have provided evidence of abnormal frontal and temporal lobe function in schizophrenia. Frontal cortex abnormalities have been associated with negative symptoms and temporal lobe abnormalities with positive symptoms. The deficit and nondeficit forms of schizophrenia were predicted to differ in prefrontal cortical activity, but not in medial temporal lobe activity. METHODS: Regional cerebral blood flow was studied using oxygen 15 positron emission tomography during 3 different memory retrieval conditions in 8 control subjects, 8 patients with the deficit syndrome, and 8 patients without the deficit syndrome. Behavioral and positron emission tomography data were analyzed using a mixed-effects model to test for population differences. RESULTS: In all memory conditions, frontal cortex activity was higher in patients without the deficit syndrome than in patients with the deficit syndrome. During the attempt to retrieve poorly encoded words, patients without the deficit syndrome recruited the left frontal cortex to a significantly greater degree than did patients with the deficit syndrome. The 2 schizophrenia subtypes did not differ in the activity or recruitment of the hippocampus during memory retrieval. CONCLUSION: Frontal cortex function during memory retrieval is differentially impaired in deficit and nondeficit schizophrenia, whereas hippocampal recruitment deficits are not significantly different between the 2 schizophrenia groups.  相似文献   

16.
Functional MRI (fMRI) studies of mild cognitive impairment (MCI) and Alzheimer's disease (AD) have begun to reveal abnormalities in memory circuit function in humans suffering from memory disorders. Since the medial temporal lobe (MTL) memory system is a site of very early pathology in AD, a number of studies, reviewed here, have focused on this region of the brain. By the time individuals are diagnosed clinically with AD dementia, the substantial memory impairments appear to be associated with not only MTL atrophy but also hypoactivation during memory task performance. Prior to dementia, when individuals are beginning to manifest signs and symptoms of memory impairment, the hippocampal formation and other components of the MTL memory system exhibit substantial functional abnormalities during memory task performance. It appears that, early in the course of MCI when memory deficits and hippocampal atrophy are less prominent, there may be hyperactivation of MTL circuits, possibly representing inefficient compensatory activity. Later in the course of MCI, when considerable memory deficits are present, MTL regions are no longer able to activate during attempted learning, as is the case in AD dementia. Recent fMRI data in MCI and AD are beginning to reveal relationships between abnormalities of functional activity in the MTL memory system and in functionally connected brain regions, such as the precuneus. As this work continues to mature, it will likely contribute to our understanding of fundamental memory processes in the human brain and how these are perturbed in memory disorders. We hope these insights will translate into the incorporation of measures of task-related brain function into diagnostic assessment or therapeutic monitoring, such as for use in clinical trials.  相似文献   

17.
《Alzheimer's & dementia》2013,9(3):284-294
BackgroundReliable blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) phenotypic biomarkers of Alzheimer’s disease (AD) or mild cognitive impairment (MCI) are likely to emerge only from a systematic, quantitative, and aggregate examination of the functional neuroimaging research literature.MethodsA series of random-effects activation likelihood estimation (ALE) meta-analyses were conducted on studies of episodic memory encoding operations in AD and MCI samples relative to normal controls. ALE analyses were based on a thorough literature search for all task-based functional neuroimaging studies in AD and MCI published up to January 2010. Analyses covered 16 fMRI studies, which yielded 144 distinct foci for ALE meta-analysis.ResultsALE results indicated several regional task-based BOLD consistencies in MCI and AD patients relative to normal control subjects across the aggregate BOLD functional neuroimaging research literature. Patients with AD and those at significant risk (MCI) showed statistically significant consistent activation differences during episodic memory encoding in the medial temporal lobe, specifically parahippocampal gyrus, as well superior frontal gyrus, precuneus, and cuneus, relative to normal control subjects.ConclusionsALE consistencies broadly support the presence of frontal compensatory activity, medial temporal lobe activity alteration, and posterior midline “default mode” hyperactivation during episodic memory encoding attempts in the diseased or prospective predisease condition. Taken together, these robust commonalities may form the foundation for a task-based fMRI phenotype of memory encoding in AD.  相似文献   

18.
The hippocampus is believed to have close relationship with many cerebral cortexes and constitute memory network to modulate and facilitate communication, which makes it especially interesting and meaningful in the study of functional connectivity in mild cognitive impairment (MCI). However, functional connectivity between the hippocampus and other brain regions remains unclear in MCI. Furthermore, the longitudinal changes of the hippocampal connectivity have not been reported. In the study, resting state functional MRI (fMRI) was used to examine changes in hippocampal connectivity comparing 14 patients and 14 healthy age-matched controls. We found that functional connectivity between the hippocampus and a set of regions was disrupted in MCI, these regions are: the right frontal lobe, the bilateral temporal lobe and the right insular. While, the left posterior cingulate cortex, precuneus, hippocampus, caudate and right occipital gyrus showed increased connectivity to the hippocampus in MCI. Additionally, we traced the seven MCI patients and compared the hippocampal connectivity in initial stage and 3 years later stage. Several regions presented decreased connectivity to the hippocampus after 3 years. Finally, the hippocampal connectivity with some regions showed significant correlation with the cognitive performance of patients. Based on these findings, the decreased hippocampal connectivity might indicate reduced integrity of hippocampal cortical memory network in MCI. In addition, the increased hippocampal connectivity suggested compensation for the loss of memory function. With the development of the disease, the hippocampal connectivity may lose some compensation and add some more disruption due to the pathological changes.  相似文献   

19.
Background/Aims: The relationship between baseline (11)C-Pittsburgh compound B ((11)C-PIB) uptake and cognitive decline during a 2-year follow-up was studied in 9 patients with mild cognitive impairment (MCI) who converted to Alzheimer's disease (AD) and 7 who remained with MCI. Methods: (11)C-PIB PET scan was conducted at baseline and cognitive assessment both at baseline and at follow-up. To obtain quantitative regional values of (11)C-PIB uptake, automated region of interest analysis was done using spatially normalized parametric ratio (region-to-cerebellar cortex) images. Results: At baseline, there were statistically significant differences in (11)C-PIB uptake, but not in cognitive test performances between the converters and nonconverters. Memory and executive function declined only in the converters during follow-up. In the converters, lower baseline frontal (11)C-PIB uptake was associated with faster decline in verbal learning. Higher baseline uptake in the caudate nucleus was related to faster decline in memory consolidation, and higher temporal uptake was associated with decline in executive function. Conclusion: Higher (11)C-PIB uptake in the caudate nucleus and temporal lobe was related to decline in memory and executive functions, whereas lower frontal uptake was related to decline in verbal learning. The results indicate that in prodromal AD, frontal amyloid accumulation reaches its maximum in the MCI stage, characterized by memory problems without full-blown dementia.  相似文献   

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