基于图论分析对人群空间导航相关脑功能网络拓扑学属性的研究

目的 探讨空间导航能力极好和空间导航能力极差人群的脑功能网络拓扑结构差异。方法 2020年9月-2021年9月,从中国人民解放军陆军边海防学院选取符合纳入标准的100名大学生,进行空间导航能力的测试,选取空间导航能力极好者（GN组）和空间导航能力极差者（PN组）各25名,采集他们的脑部静息态功能MRI及3D T1加权结构像数据。应用图论分析研究大脑网络的拓扑结构,包括全局和局部的拓扑学属性。结果 在阈值范围内,GN组和PN组在聚类系数、特征路径长度、局部效率的差异无统计学意义（P>0.05）。GN组和PN组的脑功能连接网络满足标准化的聚类系数（γ）>1、标准化的特征路径长度（λ）≈1、小世界属性（σ）>1,具有小世界网络属性,GN组的全局效率（0.22±0.01 vs. 0.21±0.01）、γ值（0.97±0.18 vs. 0.81±0.18）和σ值（0.75±0.13 vs.0.64±0.13）的曲线下面积高于PN组,差异有统计学意义（P<0.05）,两组间λ值的曲线下面积差异无统计学意义（P>0.05）。节点水平分析结果显示GN组与PN组在左侧眶部额...     

孤独谱系障碍患儿静息态功能脑网络小世界属性研究

目的 探讨孤独谱系障碍患儿静息态功能脑网络小世界属性的变化.方法 将41例孤独症患儿(研究组)与41名健康对照儿童(对照组)的脑影像数据进行预处理、构建脑网络,运用图论的方式分析所构建脑网络的小世界属性,并对两组相关指标进行统计分析.结果 两组都展示出了比较显著的小世界属性,其中研究组的聚类系数、最短路径长度、标准化路...     

孤独症谱系障碍儿童脑磁图静息态伽马频带脑功能网络探析

目的:研究孤独症谱系障碍(ASD)儿童静息态脑磁图伽马频带的脑功能网络特征.方法 :ASD儿童6名,健康对照9名.采集静息态脑磁图信号和磁共振数据,在信号源水平进行伽马频带信号在大脑皮层的功率谱密度分析,并计算相位转移熵,构建脑网络,用于患儿组和对照组比较.结果 :在脑网络节点激活程度方面,与对照组相比,患儿的伽马频带...     

阿尔茨海默病患者脑功能网络小世界属性改变及其与认知功能的相关性

目的 利用图论分析方法观察阿尔茨海默病（AD）患者脑功能网络小世界属性改变及其与认知功能的相关性。方法 对42例AD患者（AD组）和31名正常志愿者（对照组）进行神经心理学评估,并采集静息态fMRI数据,构建小世界网络,计算小世界网络属性参数,包括聚类系数（C_p）、最短路径长度（L_p）、标准化聚类系数（γ）、标准化最短路径长度（λ）及小世界性（σ）。以独立样本t检验比较2组间小世界网络属性的差异,以偏相关分析评估小世界网络属性与认知评分的相关性。结果 在不同稀疏度下,AD组及对照组σ均>1,表示AD患者及正常受试者脑功能网络均具有小世界属性。AD组小世界属性参数L_p、λ大于对照组（P均<0.05）,AD组与对照组间C_p、γ差异均无统计学意义（P均>0.05）。AD患者C_p与听觉词语学习测验（AVLT,即时）、AVLT（延迟）评分呈正相关（r=0.646,P<0.001;r=0.438,P=0.008）,L_p与AVLT（即时）评分呈负相关（r=-0.381,P=0.035）。结论 AD患者脑功能网络的小世界属性发生改变,且与情景记忆能力具有相关性。脑功能网络小世界属性改变能够较好地反映AD患者的病理生理改变。     

健康女性强烈排尿感脑功能网络的小世界特征

目的 分析同步尿动力监测下健康女性强烈排尿感时大脑功能网络连接的小世界特征.方法 2017年至2018年,招募21例健康女性受试者,在膀胱空虚和强烈排尿感时分别进行大脑静息态功能磁共振扫描.采用Pearson相关分析计算大脑功能连接矩阵;采用配对t检验和Bonferroni校正对膀胱空虚和强烈排尿感时大脑功能连接的拓扑...     

静息态脑功能磁共振成像的研究进展

人脑是目前所知的最完善、最复杂的动态信息处理系统。脑功能磁共振成像（fonctional Magnetic Resonance Imaging,f MRI）是一种新型的髙效的无辐射非介入性损伤的成像技术,现已广泛应用于脑功能研究[1]。近年来静息态脑功能磁共振成像（resting-state functional MRI,rf MRI）日益受到大家的关注,广泛应用于神经心理学和神经系统疾病影像学方面的基础与临床研究。     

自闭症儿童早期大脑过度发育的sMRI研究

目的利用结构磁共振成像(structural MRI,sMRI)提取的区域特征来研究自闭症患者的大脑发育异常情况。材料与方法收集59例年龄2~4岁的自闭症儿童和50名年龄4~10岁的正常儿童的结构磁共振数据,利用freesurfer软件提取大脑皮层厚度、灰质和白质区域体积以及从预定义的感兴趣区域(region of interest,ROI)提取的若干皮层下结构等区域特征,最后经统计分析方法计算两组的差异。结果通过对150项脑皮层与体积指标进行t检验组分析,发现自闭症患儿与正常对照组在其中66项上存在显著差异(P<0.05),与年龄较大的正常发育中的儿童相比,自闭症儿童的大脑表现出明显的过度生长模式,特别是在顶叶、枕叶、额叶、颞叶和楔前叶等区域。结论本研究证实自闭症儿童存在大脑结构过度发育现象,增加的大脑尺寸是自闭症患儿早期大脑发育的重要结构特征,这将为自闭症的早期诊断和病情评估提供了有力工具。     

阻塞性睡眠呼吸暂停患者默认网络功能连接及拓扑属性异常

目的 观察阻塞性睡眠呼吸暂停（OSA）患者脑默认网络（DMN）内部各亚区的功能连接（FC）及拓扑属性的异常改变。方法 采集40例男性重度OSA患者（OSA组）和43名睡眠正常的男性志愿者（对照组）的静息态fMRI数据,以20个DMN亚区为种子点构建DMN的FC网络,获得OSA患者DMN各亚区间FC异常的脑区。计算拓扑属性参数小世界指数（σ）、网络全局效率（E_glob）和网络局部效率（E_loc）,并评估与临床资料的相关性。结果 OSA组和对照组DMN均存在小世界属性。与对照组比较,OSA组前—后DMN、后DMN内部FC减低（P均<0.05）,E_loc减低（P=0.02）。OSA组DMN异常的FC与E_glob值（r=-0.736,P<0.001）、蒙特利尔认知（MoCA）量表评分（r=-0.453,P=0.006）呈负相关。结论 OSA患者DMN内部各亚区功能连接受损,且DMN拓扑属性异常改变,可能是其认知、记忆等功能障碍的神经影像学机制。     

基于低频振幅和局部一致性的视神经脊髓炎谱系疾病认知功能障碍的静息态脑功能成像研究

目的 探究伴认知功能障碍的视神经脊髓炎谱系疾病(neuromyelitis optica spectrum disorder,NMOSD)患者静息态脑功能低频振幅(amplitude of low frequency fluctuation,ALFF)及局部一致性(regional homogeneity,ReHo)的改变。材料与方法 前瞻性招募34名NMOSD患者及39名健康对照者进行静息态磁共振扫描及神经心理学评估,将患者根据认知评估划分为认知障碍组(n=16)及认知保留组(n=18),采用ALFF及ReHo分析探究认知障碍组、认知保留组患者及健康对照三组间自发性脑活动的差异。基于MATLAB的DPABI软件进行数据分析处理,采用两两对比的独立样本t检验对3组受试者的ALFF及ReHo脑图进行组间比较,提取差异脑区的ALFF及ReHo值与NMOSD患者的临床资料及认知分数进行相关性分析。结果 认知障碍组左侧尾状核及海马旁回ALFF值显著高于认知保留组,左侧尾状核ALFF值显著高于健康对照组,左侧中扣带回ReHo值显著低于健康对照组(GRF校正,体素水平P<0.001,团块水平...     

Quantification of changes in language-related brain areas in autism spectrum disorders using large-scale network analysis

Purpose

Diagnosis of autism spectrum disorders (ASD) is difficult, as symptoms vary greatly and are difficult to quantify objectively. Recent work has focused on the assessment of non-invasive diffusion tensor imaging-based biomarkers that reflect the microstructural characteristics of neuronal pathways in the brain. While tractography-based approaches typically analyze specific structures of interest, a graph-based large-scale network analysis of the connectome can yield comprehensive measures of larger-scale architectural patterns in the brain. Commonly applied global network indices, however, do not provide any specificity with respect to functional areas or anatomical structures. Aim of this work was to assess the concept of network centrality as a tool to perform locally specific analysis without disregarding the global network architecture and compare it to other popular network indices.

Methods

We create connectome networks from fiber tractographies and parcellations of the human brain and compute global network indices as well as local indices for Wernicke’s Area, Broca’s Area and the Motor Cortex. Our approach was evaluated on 18 children suffering from ASD and 18 typically developed controls using magnetic resonance imaging-based cortical parcellations in combination with diffusion tensor imaging tractography.

Results

We show that the network centrality of Wernicke’s area is significantly (p  $<$  0.001) reduced in ASD, while the motor cortex, which was used as a control region, did not show significant alterations. This could reflect the reduced capacity for comprehension of language in ASD.

Conclusions

The betweenness centrality could potentially be an important metric in the development of future diagnostic tools in the clinical context of ASD diagnosis. Our results further demonstrate the applicability of large-scale network analysis tools in the domain of region-specific analysis with a potential application in many different psychological disorders.     

Electroencephalogram abnormalities in children with autism spectrum disorders.

Children with an autism spectrum disorder (ASD) often are evaluated with electroencephalogram (EEG) studies to assess their risk for seizures or other underlying abnormalities. Their risk is estimated at 7% - 42%. EEG studies were conducted on a subgroup of children while following established practice parameters for evaluating children for ASD. Abnormal EEG results were obtained in 85 (27%) of the 316 children evaluatedfor ASD. Within the subset of abnormal results, 64 children had autism, 10 had an ASD or milder presentation, 6 had another developmental disorder, 3 had Rett syndrome, had Down syndrome, and 1 had Wolf-Hirshhorn syndrome. The abnormal EEG findings included epileptiform abnormalities in 55 patients (65%), and slowing in only 13 patients (15%). The focality of the epileptiformfindings included 26 (30%) in the temporal areas, 24 (28%) in the central area, 20 (23%) in the frontal area, and 7 (8%) in the occipital area. These findings confirm the importance of ongoing medicalfollow-up for children with ASDs, especially for those with abnormal EEG results.     

Out-of-school participation patterns in children with high-functioning autism spectrum disorders

PURPOSE: This study examined differences in out-of-school activity participation between typically developing children and those with high-functioning autism spectrum disorders (HFASD). METHOD: Children with HFASD, ages 6 to 12 (N = 52), and a control group (N = 53) were assessed using the Children's Assessment of Participation and Enjoyment and the Social Responsiveness Scale. RESULTS: Significant differences were seen in participation between typical and HFASD groups in number of activities in which children participate, the numbers of individuals with whom they participate, and the variety of environments in which they participate. CONCLUSIONS: These findings indicate that out-of-school participation is significantly different for children with HFASD than for typically developing peers. Findings suggest that social impairment is related to some aspects of participation and that addressing social skills in intervention could contribute to increased participation in out-of-school activities by children with HFASD, which would contribute to their long-term mental and physical health.     

Multivariate brain network graph identification in functional MRI

Motivated by recent interest in identification of functional brain networks, we develop a new multivariate approach for functional brain network identification and name it as Multivariate Vector Regression-based Connectivity (MVRC). The proposed MVRC method regresses time series of all regions to those of other regions simultaneously and estimates pairwise association between two regions with consideration of influence of other regions and builds the adjacency matrix. Next, modularity method is applied on the adjacency matrix to detect communities or functional brain networks. We compare the proposed MVRC method with existing methods ranging from simple Pearson correlation to advanced Multivariate Adaptive Sparse Representation (ASR) methods. Experimental results on simulated and real fMRI dataset demonstrate that MVRC is able to extract functional brain networks that are consistent with the literature. Also, the proposed MVRC method is 650–750 times faster compared to the existing ASR method on 90 node network.     

The challenges of screening pre-school children for autism spectrum disorders in Iran

Purpose: Early identification and diagnosis of children with autism spectrum disorder is recommended, but this is difficult to achieve in less developed countries due to a lack of suitable tools and personnel. This two-phase study, undertaken in Iran, aimed to develop culturally appropriate and feasible means for screening pre-school children for autism spectrum disorder (ASD). Method: The first phase involved information and training events held in four cities to alert parents and to recruit and train professionals to undertake screenings and diagnostic assessments. In phase 2, a screening tool developed in Iran was administered to over 20 000 preschool children with the Iranian version of the GARS2 scale used to assess the probability of the child having ASD. Results: Over 250 professionals were trained and assessed as competent screeners of whom a further 67 were trained and accredited to use GARS2. They included postgraduate students and practitioners from a range of disciplines. In all, 1579 children screened positive; however, only 130 parents brought their child for the diagnostic assessment of whom 22% had a high probability of having ASD. Conclusion: The feasibility of undertaking a screening programme for ASD with Iranian preschoolers has been demonstrated although further research is needed to refine the screening and diagnostic tools, monitor assessors and promote greater engagement of families.

• Implications for Rehabilitation

• Sizeable numbers of postgraduate students and practitioners were recruited to assist with the screening and assessments of preschoolers.

• The uptake of screening was highest among parents of four and five years olds but much less so for younger children and in bringing children for further assessments.

• Further research is needed into the development of more suitable screening and diagnostic tools for ASD with Iranian preschoolers and the training of assessors in their use.