轻度认知障碍患者视空间功能的fMRI研究

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.     

轻度认知障碍工作记忆的fMRI研究

目的 :运用血氧水平依赖 (bloodoxygenationleveldependent ,BOLD)法功能磁共振成像 (functionalmagneticresonanceimaging ,fMRI)对轻度认知障碍 (mildcognitiveimpairment ,MCI)与正常对照组在记忆的激活区域范围及强度方面进行比较。方法 :对 6例MCI患者 ,8例认知正常老人进行神经心理学测试 ,在 1 5TPick磁共振扫描仪上进行记忆过程中的EPI序列的扫描 ,并运用相关软件分析所得图像及数据。结果 :MCI患者在颞叶激活范围比正常对照组小 ,时间 信号强度变化曲线亦有差异 ,右侧颞叶激活的范围和强度均高于左侧。结论 :MCI患者的记忆功能下降在fMRI上主要表现为颞叶激活范围的变化及激活强度的下降 ,颞叶可能是MCI记忆功能下降反应比较敏感的区域。     

轻度认知障碍患者视空间工作记忆的变化

目的 探索轻度认知障碍(MCI)患者视空间工作记忆的广度和准确度的变化.方法 根据临床记忆检查和Blessed-Roth生活评定结果诊断的MCI患者20例和与之匹配的正常对照20例进行扫视记忆和重现数字位置的试验.结果 MCI组扫视记忆的正确率比对照组下降,差异有统计学意义(P<0.05).扫视的平均速度与对照组的差异无统计学意义(P>0.05).两组能正确记忆位置的数字个数差异无统计学意义(P>0.05),为达到最好的记忆效果,MCI组需要数字呈现的时间比对照组长,差异有统计学意义(P<0.05).结论 MCI患者视觉空间工作记忆的中央执行系统运转正常,视空间模板的存贮空间保留,视空间工作记忆的广度正常,而视空间初步加工系统中两种次级记忆的准确性下降,导致视空间工作记忆的准确度下降.     

脑白质病变相关性轻度认知功能障碍患者神经心理学特征分析

目的观察脑白质病变(WML)对轻度认知功能损害(mild cognitive impairment,MCI)患者神经心理学的影响。方法 WML-MCI患者和健康对照者进行常规核磁共振及神经心理学检查,观察WML对MCI患者神经心理学的影响,并对其机制进行探讨。结果 WML-MCI组与对照组相比,高血压、糖尿病和冠心病比例明显增高;词语流畅性测验、积木测验和画钟测验评分均明显降低(P<0.05);而2组间MMSE、数字广度测验和词语延迟回忆测验评分无明显差异。结论 WML影响MCI患者的认知功能,主要表现为视空间及执行功能。血管危险因素是MCI发病的危险因素。     

前扣带回与创伤后应激障碍关系的功能磁共振成像研究

目的 利用功能磁共振成像(fMRI)探讨前扣带回与创伤后应激障碍(PTSD)之间的关系.方法 对12例符合美国精神障碍诊断与统计手册第4版(DSM-Ⅳ)的创伤后应激障碍患者和12名正常对照进行可以针对性激活前扣带回的Strcop色词测验,并对其行fMRI扫描,分析两组之间前扣带回激活信号强度的差异.结果 患者组前扣带回激活的血氧依赖水平(BOLD)的信号明显弱于对照组,差异有统计学意义(P<0.05).结论 前扣带回与创伤后应激障碍存在着密切的关系.     

阿尔茨海默病和轻度认知功能障碍患者外周视神经纤维层厚度的meta分析（英文）

背景:既往研究发现阿尔茨海默病(Alzheimer’s disease,AD)和轻度认知障碍(mild cognitive impairment,MCI)患者外周视神经纤维层(retinal nerve fiber layer,RNFL)厚度显著薄于正常对照组(normal control,NC),但视神经RNFL在各个象限的具体厚度尚不清楚。目的:运用系统综述综合评估AD和MCI患者的外周RNFL厚度。方法:按照预先制定的纳入和排除标准,从PubM ed、EMBASE、ISI Web of Knowledge、Ovid/Medline、Science Direct、Cochrane Library、中国知识资源总库(CNKI)、重庆维普数据库、万方数据和中国生物医学文献服务系统(SinoM ed)筛选中英文研究。采用Review Manager5.3软件进行统计分析。结果:共纳入19项横断面研究(含合并样本量1455例)。通过比较AD或MCI患者和正常对照的RNFL,发现各研究间的异质性很大,但这种异质性主要限于低质量研究。合并其中6项高质量研究(n=578)后发现AD患者总的RNFL和上、下方象限的RNFL厚度较正常对照明显变薄。类似地,合并5项高质量研究(n=541)后发现MCI患者总的RNFL厚度显著薄于对照组。有6项研究(n=589)发现MCI患者的上、下象限RNFL比对照组薄;而另外6项研究(n=487)发现MCI患者颞象限RNFL比对照组薄。最后,有7项研究(n=432)表明AD患者的总RNFL比MCI患者薄,而有6项研究(n=364)显示AD患者的上、下象限RNFL比MCI患者薄。结论:既往研究结果的大部分异质性可能是由于方法学的不足。外周RNFL的厚度,特别是在上、下象限,在认知功能下降的同时逐渐变薄,所以这可以作为AD早期识别的候选辅助生物标记。我们需要进一步开展在方法学上更有说服力的、基于人群的队列研究来随访老年患者并同时收集潜在中介因素的信息(如血压、血糖和血脂水平),从而证实或证伪RNFL潜在的预测价值。     

认知功能筛查量表在MCI和轻度AD患者中的应用

目的:探讨认知功能筛查量表在轻度认知功能损害(Mild Cognitive Impairment,MCI)和轻度阿尔茨海默病(Alzhei mer disease,AD)患者中的应用。方法:对61例MCI患者和47例轻度AD患者进行系列神经心理学测验,同时选择41例正常老年人做对照。结果:MCI组和正常老年人比较,MGR、MMSE的短时记忆亚项、FOM、LM、DR、CDT均有统计学差异。轻度AD组和MCI组比较,MMSE的即刻记忆亚项、RVR、DS、ADL、IADL、POD均有统计学差异。CES-D在三组间无统计学差异。结论:MGR量表可用来鉴别正常人和认知功能损害人群,但不宜用来鉴别MCI和轻度AD患者。RVR和DS量表可以用于鉴别MCI和轻度AD患者。ADL量表在轻度AD患者显示损害,提示AD患者存在日常生活行为能力的损害。     

轻度认知功能障碍和轻度阿尔茨海默病患者的选择注意功能的研究

目的 了解轻度认知功能障碍(mild cognitive impairment,MCI)患者和轻度阿尔茨海默病(Alzheimer's disease,AD)患者的选择注意功能。方法 采用斯特鲁普(Stroop)测验对15例符合国际精神疾病分类第10版(ICD-10)及美国神经病学、语言障碍和卒中/老年性痴呆和相关疾病学会(NINCDs/ADRDA)标准的轻度AD患者、15例MCI患者和15例正常老年人进行对照研究。结果 冲突条件下轻度AD患者表现出更大的干扰效应,犯错误更多,反应时间也趋向于更长,MCI组和正常对照组干扰量无明显差别,但MCI组总错误率明显高于正常对照组。结论 轻度AD患者存在选择注意功能障碍,MCI患者选择注意功能下降,介于健康老人和轻度AD患者之间。     

颞叶癫痫患者警觉功能的脑功能磁共振研究

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。     

脑血管畸形患者运动皮质可塑性的功能MRI研究

目的 :探讨应用功能MRI(fMRI)研究位于或邻近初级运动中枢脑血管畸形患者运动皮质功能的可塑性。方法 :8例患者采集双手对掌运动激发后功能图像 ,观察功能区的分布特征 :计算活动指数 (AI)值 ;测量不同活动区信号强度 (SI)上升百分率。结果 :8例患者运动激发后在手运动区 (HRA)、辅助运动区 (SMA)、中央后回、额前区、顶叶等区域见活动。 5例有功能区移位的患者正常侧HRA活动区扩大 ,AI值为 0 3 9± 0 0 7,3例功能区无移位患者的AI值为 0 87± 0 12 (P <0 0 5 )。正常侧不同部位SI上升百分率均较病灶侧相应部位高 (P >0 0 5 )。结论 :脑血管畸形患者运动皮质可塑性改变表现为正常侧初级运动中枢的功能加强以及非特定手运动皮质的激活     

Reduced neuronal efficacy in progressive mild cognitive impairment: a prospective fMRI study on visuospatial processing

Mild cognitive impairment (MCI) often refers to the preclinical stage of dementia, where the majority develop Alzheimer's disease (AD). Given that neurodegenerative burden and compensatory mechanisms might exist before accepted clinical symptoms of AD are noticeable, the current prospective study aimed to investigate the functioning of brain regions in the visuospatial networks responsible for preclinical symptoms in AD using event-related functional magnetic resonance imaging (fMRI). Eighteen MCI patients were evaluated and clinically followed for approximately 3 years. Five progressed to AD (PMCI) and eight remained stable (SMCI). Thirteen age-, gender- and education-matched controls also participated. An angle discrimination task with varying task demands was used. Brain activation patterns as well as task demand-dependent and -independent signal changes between the groups were investigated by using an extended general linear model including individual performance (reaction time [RT]) of each single trial. Similar behavioral (RT and accuracy) responses were observed between MCI patients and controls. A network of bilateral activations, e.g. dorsal pathway, which increased linearly with increasing task demand, was engaged in all subjects. Compared with SMCI patients and controls, PMCI patients showed a stronger relation between task demand and brain activity in left superior parietal lobules (SPL) as well as a general task demand-independent increased activation in left precuneus. Altered brain function can be detected at a group level in individuals that progress to AD before changes occur at the behavioral level. Increased parietal activation in PMCI could reflect a reduced neuronal efficacy due to accumulating AD pathology and might predict future clinical decline in patients with MCI.     

MCI患者的注意功能障碍反应时研究

目的 探讨轻度认知功能障碍(mild cognitive impairment，MCI）患者大脑注意功能的改变。方法 应用精确计时软件DMDX编制程序，在计算机上系统的测查MCI患者的注意功能．并与正常老年人(normalcontrol，NC)对比。分别采用持续操作任务实验(continuous performance test．CPT)测查持续注意功能(MCI 17例、NC18名)。斯特鲁普(Stroop)实验测查选择注意功能(MCI19名、NC20名)．双任务实验测查分散注意能力(MCI18例、NC19名)。结果 CPT实验中，MCI患者的反应时、漏报率和虚报率与NC组间无差别。Stroop实验中．2组被试均表现出明显的干扰效应；尽管MCI组反应时干扰量和错误率干扰量与NC组差异无显著性，但一致和中性条件下的反应时长于NC组，总错误率以及一致和中性条件下的错误率高于NC组。双任务实验中MCI组和NC组间无差别。结论 与NC相比，MCI患者选择注意功能有下降趋势．持续和分散注意能力正常。     

Prefrontal Compensatory Mechanism May Enable Normal Semantic Memory Performance in Mild Cognitive Impairment (MCI)

Mild cognitive impairment (MCI) is considered as a potential transitional state between normal aging and dementia. Studies addressing semantic memory in patients with incipient dementia and MCI show inconsistent results. In the current report we focused on MCI and examined memory performance (semantic, episodic, and working memory) in addition to structural and functional magnetic resonance imaging (fMRI) measurements. We studied 6 MCI, 6 normal controls, and 4 Alzheimer disease (AD) patients. MCI participants demonstrated normal semantic memory performance while fMRI examination revealed distinct patterns of activations between MCI and normal aged subjects. According to our previous study, time courses were taken from parietal, dorsolateral‐prefrontal‐cortex (DLPFC), hippocampal formation, and fusiform gyri. A small number of activated voxels in parietal regions were depicted in MCI participants and were correlated with structural changes in this region. In contrast, significantly higher activation (intensity and number of voxels) was observed in DLPFC of MCI subjects. The overactivity seen in DLPFC of MCI may represent a compensatory mechanism that enables them to perform normally. These preliminary results suggest that functional imaging may be useful for early diagnosis of dementia and call to develop reliable tests and criteria that will enable using such methods clinically.     

Functional correlates of cognitive dysfunction in multiple sclerosis: A multicenter fMRI Study

In this multicenter study, we applied functional magnetic resonance imaging (fMRI) to define the functional correlates of cognitive dysfunction in patients with multiple sclerosis (MS). fMRI scans during the performance of the N‐back task were acquired from 42 right‐handed relapsing remitting (RR) MS patients and 52 sex‐matched right‐handed healthy controls, studied at six European sites using 3.0 Tesla scanners. Patients with at least two abnormal (<2 standard deviations from the normative values) neuropsychological tests at a standardized evaluation were considered cognitively impaired (CI). FMRI data were analyzed using the SPM8 software, modeling regions showing load‐dependent activations/deactivations with increasing task difficulty. Twenty (47%) MS patients were CI. During the N‐back load condition, compared to controls and CI patients, cognitively preserved (CP) patients had increased recruitment of the right dorsolateral prefrontal cortex. As a function of increasing task difficulty, CI MS patients had reduced activations of several areas located in the fronto‐parieto‐temporal lobes as well as reduced deactivations of regions which are part of the default mode network compared to the other two groups. Significant correlations were found between abnormal fMRI patterns of activations and deactivations and behavioral measures, cognitive performance, and brain T2 and T1 lesion volumes. This multicenter study supports the theory that a preserved fMRI activity of the frontal lobe is associated with a better cognitive profile in MS patients. It also indicates the feasibility of fMRI to monitor disease evolution and treatment effects in future studies. Hum Brain Mapp 35:5799–5814, 2014. © 2014 Wiley Periodicals, Inc.     

Longitudinal change in neuropsychological performance using latent growth models: a study of mild cognitive impairment

The goal of the current study was to examine cognitive change in both healthy controls (n?=?229) and individuals with mild cognitive impairment (MCI) (n?=?397) from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). We applied latent growth modeling to examine baseline and longitudinal change over 36 months in five cognitive factors derived from the ADNI neuropsychological test battery (memory, executive function/processing speed, language, attention and visuospatial). At baseline, MCI patients demonstrated lower performance on all of the five cognitive factors when compared to controls. Both controls and MCI patients declined on memory over 36 months; however, the MCI patients declined at a significantly faster rate than controls. The MCI patients also declined over 36 months on the remaining four cognitive factors. In contrast, the controls did not exhibit significant change over 36 months on the non-memory cognitive factors. Within the MCI group, executive function declined faster than memory, while the other factor scores changed slower than memory over time. These findings suggest different patterns of cognitive change in healthy older adults and MCI patients. The findings also suggest that, when compared with memory, executive function declines faster than other cognitive factors in patients with MCI. Thus, decline in non-memory domains may be an important feature for distinguishing healthy older adults and persons with MCI.     

Toward systems neuroscience in mild cognitive impairment and Alzheimer's disease: A meta‐analysis of 75 fMRI studies

Most of the previous task functional magnetic resonance imaging (fMRI) studies found abnormalities in distributed brain regions in mild cognitive impairment (MCI) and Alzheimer's disease (AD), and few studies investigated the brain network dysfunction from the system level. In this meta‐analysis, we aimed to examine brain network dysfunction in MCI and AD. We systematically searched task‐based fMRI studies in MCI and AD published between January 1990 and January 2014. Activation likelihood estimation meta‐analyses were conducted to compare the significant group differences in brain activation, the significant voxels were overlaid onto seven referenced neuronal cortical networks derived from the resting‐state fMRI data of 1,000 healthy participants. Thirty‐nine task‐based fMRI studies (697 MCI patients and 628 healthy controls) were included in MCI‐related meta‐analysis while 36 task‐based fMRI studies (421 AD patients and 512 healthy controls) were included in AD‐related meta‐analysis. The meta‐analytic results revealed that MCI and AD showed abnormal regional brain activation as well as large‐scale brain networks. MCI patients showed hypoactivation in default, frontoparietal, and visual networks relative to healthy controls, whereas AD‐related hypoactivation mainly located in visual, default, and ventral attention networks relative to healthy controls. Both MCI‐related and AD‐related hyperactivation fell in frontoparietal, ventral attention, default, and somatomotor networks relative to healthy controls. MCI and AD presented different pathological while shared similar compensatory large‐scale networks in fulfilling the cognitive tasks. These system‐level findings are helpful to link the fundamental declines of cognitive tasks to brain networks in MCI and AD. Hum Brain Mapp 36:1217–1232, 2015. © 2014 Wiley Periodicals, Inc.     

强迫症患者抑制功能受损的脑影像学特征

目的分析强迫症患者是否存在抑制功能受损,及其抑制功能受损的脑影像学特征。方法16例首次发病未用药的强迫症患者(强迫症组)和18名健康对照者(对照组)完成测查抑制功能的Go-Nogo任务,同步采集被试者任务态脑影像数据。采用方差分析比较强迫症组和对照组在Go条件和Nogo条件下平均反应时和反应正确率的组间差异,以及在成功反应抑制与错误监测过程中脑激活特征的组间差异。结果在Nogo条件下,强迫症组的正确率显著低于对照组(0.85±0.08比0.93±0.51;t=-3.06,P<0.05);在错误监测过程中,2组大脑激活模式存在差异,强迫症组双侧颞下回(左侧:t=3.11;右侧:t=2.71)、右侧额中回(t=2.52)、右侧海马旁回(t=2.53)、左侧后扣带回(t=3.03)大脑活动增强(均P<0.05);双侧壳核(左侧:t=-3.03;右侧:t=-3.12)、右侧额下回(t=-3.29)、右侧额上回(t=-3.12)、右侧中央前回(t=-2.91)大脑活动显著降低(均P<0.05)。结论强迫症患者存在抑制功能受损,在错误监测过程中相关脑区的功能活动存在异常。     

The effects of noninvasive brain stimulation on cognitive function in patients with mild cognitive impairment and Alzheimer's disease using resting-state functional magnetic resonance imaging: A systematic review and meta-analysis

Objective

The aim of this systematic review and meta-analysis was to evaluate the efficacy of noninvasive brain stimulation (NIBS) on cognition using functional magnetic resonance imaging (fMRI) in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD), thus providing the neuroimaging mechanism of cognitive intervention.

Methods

English articles published up to April 30, 2023 were searched in the PubMed, Web of Science, Embase, and Cochrane Library databases. We included randomized controlled trials where resting-state fMRI was used to observe the effect of NIBS in patients with MCI or AD. RevMan software was used to analyze the continuous variables, and SDM-PSI software was used to perform an fMRI data analysis.

Results

A total of 17 studies comprising 258 patients in the treatment group and 256 in the control group were included. After NIBS, MCI patients in the treatment group showed hyperactivation in the right precuneus and decreased activity in the left cuneus and right supplementary motor area. In contrast, patients in the control group showed decreased activity in the right middle frontal gyrus and no hyperactivation. The clinical cognitive scores in MCI patients were significantly improved by NIBS, while not in AD. Some evidence regarding the modulation of NIBS in resting-state brain activity and functional brain networks in patients with AD was found.

Conclusions

NIBS could improve cognitive function in patients with MCI and AD. fMRI evaluations could be added to evaluate the contribution of specific NIBS treatment therapeutic effectiveness.     

Reorganization of verbal and nonverbal memory in temporal lobe epilepsy due to unilateral hippocampal sclerosis

PURPOSE: Patients with temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS) often suffer from material-specific memory impairments. The purpose of this study was to use functional magnetic resonance imaging (fMRI) to study the organization of specific memory functions in these patients. METHODS: We report 14 patients with unilateral TLE and HS, and 10 controls, performing an fMRI memory paradigm of word, picture, and face encoding. RESULTS: Compared with controls, patients with left TLE demonstrated less left MTL and greater right MTL activation and patients with right TLE demonstrated less right MTL and greater left MTL activation. Correlations between fMRI activation and memory performance revealed greater activation in the damaged left hippocampus to be correlated with better verbal memory performance in left TLE patients and greater right hippocampal activation to be correlated with better nonverbal memory in right TLE patients. Conversely, greater fMRI activation in the contralateral hippocampus correlated with worse memory performance. CONCLUSIONS: Our findings suggest that memory function in unilateral TLE is better when it is sustained by activation within the damaged hippocampus and that reorganization to the undamaged MTL is an inefficient process, incapable of preserving memory function.