静息状态功能磁共振成像观察轻度阿尔茨海默病后扣带回功能连通性的变化

目的 利用静息状态功能磁共振成像(fMRI)研究阿尔茨海默病(AD)早期后扣带回相关的静息脑网络连通性是如何变化的.方法 运用fMRI研究了16例轻度AD患者和16名健康对照者在静息状态后扣带回的功能连通性.与后扣带回有功能连通性的脑区是通过检测低频波动信号的时程相关性获得的.应用通用的SPM2图像统计软件计算组间和组内连通性差异,激活区阈值设置:P<0.01(校正),像素范围>5.利用SPM2软件随机效应分析t检验(经校正P<0.01,t=2.47,像素范围>5),比较患者组和对照组连通性激活的脑区.结果 与后扣带回有功能连通性减弱的脑区包括前额叶中线区、楔前叶、双侧视皮质、双侧颞下回、左侧海马、右侧丘脑、右侧额叶背外侧区;偏左侧化的连通性增高的脑区包括前额叶中线区、左侧颞下回、左侧基底节区、双侧额叶背外侧区及左侧中央前区.结论 与后扣带回相关的静息状态脑网络连通性减低与AD早期情节记忆损害和高级视觉功能损害有关系,轻度AD保留着功能连接的重塑性以便维持脑功能.静息fMRI是一种探索AD脑功能机制的适宜方法.     

基于ReHo方法的精神分裂症幻听患者静息态fMRI的研究

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.     

精神分裂症首次发病未治疗患者静息态下局部脑区自发活动的研究

目的探讨精神分裂症首次发病未治疗患者静息态下局部脑区自发活动的情况:方法:利用低频振幅(ALFF)方法,对27例首次发病未治疗的精神分裂症患者(患者组)进行静息状态下功能磁共振(fMRI)扫描,对影像学数据进行ALFF方法处理,结果与22名年龄、性别及受教育程度相匹配的健康对照者(正常对照组)比较。结果:与正常对照组相比,患者组ALFF显著增高的脑区是运动前区、辅助运动区和眶额回;ALFF显著降低的脑区是楔前叶、后扣带回、内侧前额叶和角回(P0.05,Alphaism矫正)。结论:精神分裂症首次发病未治疗患者在静息态下运动前区、辅助运动区、眶额回、楔前叶、后扣带回、内侧前额叶和角回的局部脑区自发活动异常,这些异常脑区可能有助于解释精神分裂症的病理机制。     

创伤后应激障碍患者杏仁核为主的边缘系统静息态脑功能磁共振研究

目的 观察静息状态下创伤后应激障碍(posttraumatic stress disorder,PTSD)患者以杏仁核为主的脑区的脑功能改变.方法 采用基于低频振幅(amplitude of low frequency fluctuation,ALFF)算法的静息功能磁共振成像技术(fMRI)对10例临床确诊的PISD患者和10例性别、年龄及受教育年限匹配的正常对照进行静息fMRI检查,采用t检验比较两组的杏仁核等脑区基于血氧水平依赖活动的差异.结果 与正常对照组相比,PTSD患者组右侧杏仁核ALFF活性明显增加(P<0.01),海马旁回、钩回等边缘系统其他脑区亦见ALFF活性增加(P<0.01),而前额叶、岛叶及楔前叶ALFF活性减低(P<0.01).结论 PTSD患者静息态下包括杏仁核在内的边缘系统多个脑区活动增强,前额叶、岛叶、楔前叶等脑区功能抑制.     

无灶性癫痫患者静息态fMRI与注意功能的相关性研究

目的采用静息态功能磁共振成像的低频振幅技术,探讨无灶性癫痫患者低频振幅与注意功能之间可能存在的关系。方法对16例无灶性癫痫患者和16名正常志愿者进行静息态fMRI数据采集及注意功能行为学测试,采用REST软件计算显示无灶性癫痫患者相对于正常人ALFF增高和减弱的区域,对上述的16例无灶性癫痫患者和16例正常对照进行气球叉掉测试,数字符号转换测试及stroop测试检测其注意功能,观察无灶性癫痫患者静息态fMRI与注意功能之间可能存在的联系。结果①无灶性癫痫组和正常对照组相比,ALFF增强的脑区分布在右侧颞叶(15,-90,21)、内侧额叶(0,24,-24)、腹侧前扣带回(-12,30,27)及右侧小脑半球(-51,-57,-4);②无灶性癫痫组和正常对照组相比ALFF减弱的脑区分布在左侧小脑半球及相邻后缘枕叶(-48,-15,39)、后扣带回(60,-21,33)及楔前叶(-6,-54,66);③无灶性癫痫患者的三项注意功能测试反应时间均较正常对照组延长(P<0.01)。Stroop测试结果表明无灶性癫痫组与对照组相比冲突条件下较一致、中性条件下的错误率显著增加。结论无灶性癫痫患者静息状态下表现出异常的脑功能活动方式。长期异常放电对患者的注意功能有明显损害,其中持续注意能力下降,可能与无灶性癫痫患者的颞叶及额叶的病变相关;选择注意能力下降,可能与腹侧前扣带回的损伤密切相关。     

慢性精神分裂症患者加服利培酮治疗静息态功能磁共振研究

目的:应用功能磁共振(fMRI)分析慢性精神分裂症(SCH)患者加服利培酮治疗前后静息态大脑影像改变。方法:采集慢性SCH患者9例和正常对照组9名的一般人口学资料、临床资料及基线、治疗12周后静息态fMRI数据,对采集的数据进行统计学分析。结果:与正常对照组比较,SCH组服药前静息态下局部一致性(ReHo)及低频振幅(ALFF)均有若干脑区存在差异;SCH组在利培酮治疗12周后,ReHo及ALFF发生改变。结论:慢性精神分裂症患者存在明显的认知功能异常及静息态脑fMRI异常;慢性精神分裂症患者中加服或改服利培酮可改善患者的认知功能和阳性、阴性症状,且脑影像学有相应改变。     

抑郁症首次发病患者静息态脑功能局部一致性的研究

目的 利用功能磁共振(fMRI)和局部一致性(regional homogeneity,ReHo)探讨抑郁症首次发病(以下简称首发)患者在静息态脑功能是否存在异常及异常部位.方法 对34例符合美国精神疾病诊断与统计手册第4版诊断标准的首发抑郁症患者(抑郁症组)和34名性别、年龄、文化程度匹配的健康志愿者(对照组)进行静息态fMRI扫描.结果 抑郁症组静息态脑血氧水平依赖信号的ReHo高于对照组的脑区有左侧额叶眶回、顶下小叶、颞上回,右侧额内侧回、顶下小叶、小脑后叶;低于对照组的脑区有左颞下回、右颞上同和胼胝体、双侧后扣带回(P＜0.005,K≥10).结论首发抑郁症患者在静息态存在多个腩区功能活动的异常,并可能和抑郁症的病理机制有关.     

产后抑郁症患者低频振幅变化的静息态功能磁共振成像研究北大核心CSCD

目的 探讨产后抑郁症(postpartum depression,PPD)患者静息状态下局部神经元自发神经活动变化特征及其与抑郁程度的相关性.方法 采用3.0T静息态fMRI采集26例PPD患者(PPD组)和与之匹配的26名健康产妇(对照组)影像学数据;采用双样本t检验比较组间低频振幅(amplitude of low frequency fluctuation,ALFF)值,将差异脑区ALFF值与爱丁堡产后抑郁量表(Edinburgh Postnatal Depression Scale,EPDS)得分进行相关性分析.结果 与对照组相比,PPD组双侧背内侧前额叶、岛叶ALFF值减低,双侧颞下回、左侧小脑ALFF值增高(单个体素P<0.005,体素值>26,Alphasim校正);右背内侧前额叶ALFF值与EPDS得分呈负相关(r=-0.45,P=0.035).结论 PPD患者自我认知与情绪调节相关脑区自发神经活动存在异常,右背内侧前额叶ALFF值越低的患者抑郁程度更严重.     

早发精神分裂症静息态脑功能低频振幅研究

目的通过静息态功能磁共振研究早发未用药精神分裂症患者局部脑功能低频振幅(amplitude of low-frequency fluctuation,ALFF)的变化,探讨其静息态下功能异常的脑区。方法收集20例早发未用药精神分裂症患者与20名性别、年龄、受教育年限相匹配的正常对照,分别对其进行全脑静息态功能磁共振扫描,计算ALFF值。结果与对照组相比,患者组左侧额上回、左侧楔前叶、左侧扣带回、左侧枕叶、左侧海马旁回、左侧距状沟ALFF值增高(P0.05,Alpha Sim校正),右侧颞上回和右侧小脑后叶ALFF值降低(P0.05,Alpha Sim校正)。结论早发精神分裂症患者在静息态下有多处脑区ALFF值改变,提示其在静息态下存在脑功能异常。     

静息态功能磁共振技术在阿尔茨海默病和轻度认知功能损害中的应用

静息态功能磁共振成像技术(rs-fMRI)作为一种先进的测量静息状态下脑部自发神经活动的方法,已广泛应用于阿尔茨海默病(AD)和轻度认知功能损害(MCI)的研究.近年来,采用包括功能连接、局部一致性、低频振幅及全脑图理论等分析方法进行研究,发现AD和MCI的脑区内及脑区间功能活动均有不同程度的改变,以默认网络(DMN)最为显著.本文将对近年来rs-fMRI在AD和MCI两方面的研究进展进行综述.     

Epilepsy and anomalies of neuronal migration: MRI and clinical aspects

Neuronal migration disorders are the result of disturbed brain development. In such disorders, neurons are abnormally located. In diagnosing these conditions, magnetic resonance imaging is superior to any other imaging technique. This enables us to improve our knowledge of the clinical correlates of neuronal migration. With reference to migrational disorder, a retrospective study of all 303 patients with epileptic seizures referred for magnetic resonance imaging during a 3-year period was performed, 13 patients (aged 12-41, mean age 27) were identified. They represent 4.3% of the entire study group. Of the patients with known epilepsy, 6.7% and of the mentally retarded, 13.7% had migrational disorders. Four patients had schizencephaly as the dominant finding, one was classified as hemimegalencephaly, 2 had isolated heterotopias, and 6 had localized pachy- and/or poly-microgyria. The clinical pictures are complex. Ectopias of grey matter are recognised foci of epilepsy, but from an epileptological and a clinical viewpoint little attention has been given to these disorders. The present study shows that malmigration is not rare in epilepsy patients, especially not in the mentally retarded.     

Hepatic Considerations in the Use of Antiepileptic Drugs

Summary: Virtually all of the major antiepileptic drugs (AEDs) can cause hepatotoxicity, although fatal hepatic reactions are rare. The mechanisms, incidences, and risk profiles for such reactions differ from drug to drug. With carbamazepine and phenytoin, hepatotoxicity may be due to drug hypersensitivity. Although the profiles of patients at risk have not been well-defined for these two antiepileptic drugs, it would appear from reports in the literature that older adolescents and adults are at higher risk than children of developing serious or fatal hepatotoxicity. Once hepatotoxicity develops, mortality rates are 10–38% with phenytoin and 25% for carbamazepine. The risk profile for valproate fatal hepatotoxicity has been more clearly defined. Those at primary risk of fatal hepatic dysfunction are children under the age of 2 years who are receiving multiple anticonvulsants and also have significant medical problems in addition to severe epilepsy. The risk is considerably lower for patients over the age of 2 years on valproate monotherapy. In contrast to the risk profile with other AEDs, adults receiving valproate as monotherapy have the lowest risk of hepatotoxicity. Fatal hepatic dysfunction coincident with valproate may be the result of aberrant drug metabolism. Concomitant use of AEDs that induce microsomal P450 enzymes (e.g., phenytoin and phenobarbital) may enhance the production of a toxic metabolite, and hence the greater risk of hepatotoxicity with polypharmacy.     

Vascular Malformations and Epilepsy: Clinical Considerations and Basic Mechanisms

Summary: Vascular malformations (VMs) are associated with epilepsy. The natural history of the various VMs, clinical presentation, and tendency to provoke epilepsy determine treatment strategies. Investigations have probed the mechanisms of epileptogenesis associated with these lesions. Electrophysiologic changes are associated with epileptogenic cortex adjacent to VMs. Putative pathophysiologic mechanisms of epileptogenesis include neuronal cell loss, glial proliferation and abnormal glial physiology, altered neurotransmitter levels, free radical formation, and aberrant second messenger physiology.     

Classification of methods in transcranial Electrical Stimulation (tES) and evolving strategy from historical approaches to contemporary innovations

Transcranial Electrical Stimulation (tES) encompasses all methods of non-invasive current application to the brain used in research and clinical practice. We present the first comprehensive and technical review, explaining the evolution of tES in both terminology and dosage over the past 100 years of research to present day. Current transcranial Pulsed Current Stimulation (tPCS) approaches such as Cranial Electrotherapy Stimulation (CES) descended from Electrosleep (ES) through Cranial Electro-stimulation Therapy (CET), Transcerebral Electrotherapy (TCET), and NeuroElectric Therapy (NET) while others like Transcutaneous Cranial Electrical Stimulation (TCES) descended from Electroanesthesia (EA) through Limoge, and Interferential Stimulation. Prior to a contemporary resurgence in interest, variations of transcranial Direct Current Stimulation were explored intermittently, including Polarizing current, Galvanic Vestibular Stimulation (GVS), and Transcranial Micropolarization. The development of these approaches alongside Electroconvulsive Therapy (ECT) and pharmacological developments are considered. Both the roots and unique features of contemporary approaches such as transcranial Alternating Current Stimulation (tACS) and transcranial Random Noise Stimulation (tRNS) are discussed. Trends and incremental developments in electrode montage and waveform spanning decades are presented leading to the present day. Commercial devices, seminal conferences, and regulatory decisions are noted. We conclude with six rules on how increasing medical and technological sophistication may now be leveraged for broader success and adoption of tES.     

Carbamazepine Efficacy and Utilization in Children

Summary: Carbamazepine is effective for preventing partial and generalized tonic-clonic seizures in children. Although absence epilepsies are more common in children than adults, an estimated 80% of children with epilepsy have seizure types or epilepsies that are potentially responsive to carbamazepine. The differential diagnosis of ictal staring is an especially important issue in children because absence and atypical absence seizures are more prevalent in children than adults. Age-related pharmacokinetic differences and drug interactions are major considerations in children. On average, children have higher clearance rates of carbamazepine, shorter half-lives, and higher ratios of carbamazepine-10, 11-epoxide to carbamazepine than adults. In addition, children with severe epilepsy are more likely to require multiple-drug therapy, which can lead to complex drug interactions. When carbamazepine is administered along with valproate, drug protein binding interactions can cause intermittent side effects.     

Neonatal Seizures: Problems in Diagnosis and Classification

Summary: The clinical identification of neonatal seizures is critical for the recognition of brain dysfunction; however, diagnosis is often difficult because of the poorly organized and varied nature of these behaviors. Current classification systems are limited in their ability to communicate motor, autonomic, and electroencephalo-graphic features of seizures precisely and to provide a basis for uniform effective diagnosis, therapy, and determination of prognosis. Recent investigations of neonates, utilizing bedside electroencephalographic/polygraphic/ video monitoring techniques, have provided the basis for improved diagnosis and classification of seizures in the newborn. These studies have demonstrated that not all clinical phenomena currently considered to be seizures require electrocortical epileptiform activity for their initiation or elaboration. In addition, the specific clinical character of the phenomena considered to be seizures, the clinical state of the infant, and the character of the EEG indicate the probable pathophysiological mechanisms involved and suggest probable etiologies, prognosis, and therapy. Similarities between animal models that demonstrate reflex physiology and neonates with motor automatisms and tonic posturing suggest that these clinical behaviors may not be epileptic in origin but, rather, primitive movements of progression and posture mediated by brainstem mechanisms. Although not all clinical behaviors currently considered to be neonatal seizures may have similar pathophysiological mechanisms, they are clinically significant because they all indicate brain dysfunction.     

Valproate Monotherapy in the Management of Generalized and Partial Seizures

Summary: For decades, therapeutic tradition has promoted the concept of polypharmacy in the management of epilepsy. In recent years, however, studies have shown that, for most patients, monotherapy can provide comparable or better seizure control than administration of multiple anticonvulsants, while diminishing the potential for adverse reactions, drug interactions, and poor compliance. Valproate is an important monotherapeutic agent that is highly effective in the control of idiopathic primary and secondarily generalized epilepsies, and partial seizures that do not generalize. Comparative studies have found that valproate is at least as effective as phenytoin and carbamazepine in the treatment of generalized and partial seizures. Given the similar efficacy, other factors such as pharmacokinetics and side effects may therefore determine anticonvulsant selection for monotherapy.     

Un nouveau cadre conceptuel de travail pour la psychiatrie

In an attempt to place psychiatric thinking and the training of future psychiatrists more centrally into the context of modern biology, the author outlines the beginnings of a new intellectual framework for psychiatry that derives from current biological thinking about the relationship of mind to brain. The purpose of this framework is twofold. First, it is designed to emphasize that the professional requirements for future psychiatrists will demand a greater knowledge of the structure and functioning of the brain than is currently available in most training programs. Second, it is designed to illustrate that the unique domain which psychiatry occupies within academic medicine, the analysis of the interaction between social and biological determinants of behavior, can best be studied by also having a full understanding of the biological components of behavior.