后部皮质萎缩的临床及影像学特点

目的后部皮质萎缩(posterior cortical atrophy,PCA)是以视觉障碍为突出表现,并伴进行性认知功能受损的神经系统退行性疾病。PCA的临床表现以视觉加工、计算力下降、阅读书写能力受损为主,患者的视觉认知损害突出,而情景记忆、语言能力和自知力相对保留。本文结合我院收治PCA病例,总结PCA的临床及影像学特征,以期为该病的早期诊治提供参考。方法收集2013年至2018年于宣武医院神经内科确诊的后部皮质萎缩8例患者的临床表现、神经心理学检查、影像学资料等各项检查结果并进行回顾性分析。结果8例PCA患者起病均为隐袭起病,病情进展缓慢,其中有5例符合背侧型后部皮质萎缩特点,临床表现为巴林特综合征、视空间功能障碍以及格茨曼综合征特点,头MRI显示顶枕叶皮质萎缩为主;另3例符合腹侧型后部皮质萎缩特点,临床表现主要为面孔失认、视觉忽视,头MRI显示双侧颞枕叶皮质萎缩为主,而内侧颞叶和海马萎缩程度相对较轻。8例患者均行SPECT检查,显示大脑后部包括顶叶、颞枕叶皮质血流低灌注现象。3例患者行18F FDG PET检查显示大脑后部枕叶、顶叶、颞叶皮质葡萄糖代谢降低。结论对于存在视觉障碍和后部皮质相关认知功能损害的患者,临床医生要考虑到PCA的诊断,特别注意进行视觉相关的全面的神经心理学评估及PET检查,以辅助进行PCA的诊断。     

大脑后部皮质萎缩

大脑后部皮质萎缩(PCA)是一种罕见的进展性痴呆,主要以皮层视觉功能障碍为特征的临床独立综合征。在行为和病理生理上类似阿尔茨海默病(AD),但与其又有明显的差异。常以视觉失认为首发症状,逐渐出现失读、失写、失命名、环境失认、结构性失认,最终发展为部分或完全性的Balint综合征和Gerstman综合征及经皮质感觉性失语。语言和记忆功能到疾病的晚期才受到损害。PCA的概念、流行病学、病理生理、临床表现、神经检查、评估和诊断将在本文中回顾。     

可逆性后部脑病综合征临床及影像学特点

目的 探讨可逆性后部脑病综合(RPES)的临床特征和MRI表现.方法 回顾分析22例经临床诊断RPES的临床表现、MRI资料.结果 大多有血压升高,神经症状有头痛、癫痫发作、精神症状、视觉障碍等;MRI病灶主要对称分布于枕叶及顶叶后部,主要累及皮质或皮质下白质,对症治疗后复查MRI病灶基本消失.结论 RPES是一种可逆性后部脑灰白质受累为主要特征的一个临床神经影像综合征.     

大脑后部皮质萎缩痴呆的特点

大脑后部皮质萎缩(posterior cortical atrophy,PCA)是指以顶枕叶为主的大脑后部皮质萎缩,临床表现为伴有视觉感知、空间记忆、视空间判断功能缺损的痴呆症状.病理学方面,主要是典型阿尔茨海默病(typical Alzheimer's disease,tAD)的改变,即老年斑和神经原纤维缠结(NFT).     

不同类型痴呆脑代谢改变图型:~(18)F-FDG PET显像

目的探讨不同类型痴呆患者基于像素水平的脑代谢图型特点。方法对最终临床诊断为阿尔茨海默病(20例)、额颞叶痴呆(20例)、路易体痴呆(10例)、进行性核上性麻痹(7例)、原发性进行性失语(3例)、皮质基底节变性(1例)和多系统萎缩(1例)等认知功能障碍患者的18F-FDG PET显像资料进行回顾分析,描述各种神经变性疾病脑代谢降低区域和程度。结果 SPM分析表明,各种神经变性疾病引起的痴呆18F-FDG PET显像均表现为皮质代谢降低,但其代谢图型变化明显不同:阿尔茨海默病组以双侧颞顶叶和额叶皮质代谢降低为主,基本感觉运动皮质、枕叶、基底节和丘脑活性保留;额颞叶痴呆组额叶和颞叶皮质不对称性代谢降低,伴部分顶叶皮质和基底节、丘脑等皮质下核团不同程度代谢降低;路易体痴呆组枕叶、视皮质和双侧颞上回前部代谢降低;进行性核上性麻痹组双侧前额叶背外侧、颞叶前外侧、中脑和双侧尾状核代谢降低;原发性进行性失语组左侧额叶Broca区、左侧颞叶皮质(除左侧颞上回后部)和右侧颞叶内侧皮质代谢降低;皮质基底节变性组双侧中央沟周围额顶叶皮质(右侧显著)、右侧基底节代谢降低;多系统萎缩组双侧小脑背外侧皮质和左侧壳核代谢降低。结论神经变性疾病所致痴呆在18F-FDG PET显像中表现出各自特征性脑代谢降低图型,18F-FDG PET显像有可能成为痴呆鉴别诊断的一种辅助手段。     

可逆性后部白质脑病综合征

可逆性后部白质脑病综合征(RPLS)是一组由多种原因引起的以神经系统异常为主要表现的综合征,临床表现以迅速进展的颅高压症状、癫发作、视觉障碍、意识障碍、精神异常为特征,神经影像学上显示以双侧大脑后部白质为主的水肿区,经及时有效治疗后临床表现和神经影像学改变可以完全恢复,一般不遗留有神经系统后遗症。核磁共振新技术的发展,突出显示了血管源性水肿的特点,有助于RPLS的正确诊断。     

多发性硬化认知功能障碍研究进展

认知功能障碍是多发性硬化（multiple sclerosis, MS）的常见非运动症状，主要表现在信息处理、记忆力、注意力、执行力和视觉空间能力等多个认知域受损；目前尚未形成统一的针对MS认知功能障碍的诊断标准和神经心理学检测方法；MS认知功能障碍的影响因素包括人口学因素、疾病相关因素、共病及生活方式等；影像学上主要表现为局灶性白质损伤、皮质和深部灰质萎缩；疾病修正治疗和认知康复治疗对认知功能的改善有积极影响。神经科医师应注重MS认知功能障碍的早期评估和干预，以改善患者生活质量。     

多系统萎缩17例临床分析和一例尸检报告

目的分析多系统萎缩的临床、病理特点和诊断标准.方法按Gilman诊断标准,回顾性分析了17例多系统萎缩的临床资料和其中1例病理资料.结果按Gilman诊断标准,本组17例中,确诊多系统萎缩1例,拟诊12例,可疑者4例.首发症状表现为植物神经功能障碍者8例,锥体外系体征8例.病程中出现姿位性低血压的有12例;排尿障碍16例,阳痿9例;帕金森综合征症状12例;共济失调13例;皮质脊髓束损害12例.头颅MRI发现10例脑萎缩.1例经尸检证实存在少突胶质细胞包涵体.结论多系统萎缩是累及植物神经、锥体外系、小脑和皮质脊髓束,并具少突胶质细胞包涵体等特定神经病理表现的变性疾病.Gilman诊断标准具有较强的临床可操作性.     

多系统萎缩17例临床分析和一例尸检报告

目的 分析多系统萎缩的临床、病理特点和诊断标准。方法 按Gilman诊断标准,回顾性分析了17例多系统萎缩的临床资料和其中1例病理资料。结果 按Gilman诊断标准,本组17例中,确诊多系统萎缩1例,拟诊12例,可疑者4例。首发症状表现为植物神经功能障碍者8例,锥体外系体征8例。病程中出现姿位性低血压的有12例;排尿障碍16例,阳痿9例;帕金森综合征症状12例;共济失调13例;皮质兴髓束损害12例。头颅MRI发现10例脑萎缩。1例经尸检证实存在少突胶质细胞包涵体。结论 多系统萎缩是累及植物神经、锥体外系、小脑和皮质脊髓束,并具少突胶质细胞包涵体等特定神经病理表现的变性疾病。Gilman诊断标准具有较强的临床可操作性。     

HELLP综合征合并可逆性后部白质脑病1例报告

正可逆性后部白质脑病(reversible posterior leukoencephalopathy syndrome,RPLS),是一种临床影像疾病,其影像学特点为可逆性的大脑后部皮质和皮质下水肿,临床上可表现为头痛、恶心呕吐、癫痫、视觉异常和意识障碍等。溶血、血小板减少及肝酶异常(hemolysis,elevated liver enzymes and low platelets,HELLP)综合征是妊娠高血压疾病的严重并发症,以溶     

Diagnostic Difficulties and Treatment Implications

Summary: Differentiation between types of epileptic seizures has been aided in recent years by the introduction of intensive neurodiagnostic techniques and the development of increasingly detailed classification systems. Paradoxically, these developments have not simplified the task of matching the appropriate antiepileptic drug to a particular seizure type. It is reasonable to assume that anticonvulsant drugs will have different effects on different types of seizures, but faulty, circular reasoning can enter the picture if one also assumes that responses of seizures to different drugs signify different seizure types. There are several examples of differential diagnoses that can fall prey to this problem, including the diagnosis between partial seizures with secondary generalization and generalized tonic-clonic seizures, and the diagnosis between complex partial seizures and absence seizures with automatisms, among others. Considerations of etiology in future classification systems can further complicate the problem: should one then choose an anticonvulsant drug on the basis of individual seizure type or on the basis of the type of epilepsy? Ramifications of this issue extend even to the drug approval process. Official sanction is not given for use of a drug for a seizure type not included in the original efficacy studies, even if later scientific evidence shows that seizure type to be related to a type that is included. New trials must be undertaken. These problems arise from how we choose to classify seizures.     

Cognitive Dysfunction Associated with Antiepileptic Drug Therapy

Summary: Epilepsy is frequently associated with cognitive dysfunction. However, the reasons for this correlation are unclear. Possible influential factors include patient age; duration, frequency, etiology, and type of seizures; hereditary factors; psychosocial issues; and antiepileptic drug (AED) therapy. Whereas many of these factors are beyond the physician's control, AED therapy is one element that can be addressed in treatment decisions by recognizing the potential cognitive effects of particular AEDs. For example, phenobarbital impairs memory and concentration; phenytoin affects attention, problem solving ability, and performance of visuomotor tasks. In contrast, carbamazepine may affect concentration, while valproate would appear to have minimal effects on cognition. Moreover, cognitive effects of AEDs are amplified with coadministration of multiple anticonvulsants (polytherapy). A review of studies on the cognitive effects of monotherapy with AEDs, as opposed to those of polytherapy, provides evidence that drug-related cognitive dysfunction can be reversed if patients are switched to a simpler therapeutic regimen. Future research should be directed toward developing reliable measures for assessing and monitoring cognition, and understanding the particular cognitive side effects of each AED. Physicians also need to revise their opinions about which side effects are "tolerable" for epileptic patients.     

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.     

Carbamazepine Efficacy in Adults With Partial and Generalized Tonic-Clonic Seizures

Summary: Carbamazepine and phenytoin are drugs of choice in initial monotherapy for adult partial and secondarily generalized tonic-clonic seizures. These designations reflect the results of the Veterans Administration Epilepsy Cooperative Study Group of 1985. An earlier comparative study of carbamazepine and phenytoin by Ramsay and associates found both drugs equally effective in controlling new-onset seizures. Among the advantages of carbamazepine is that it causes relatively few cognitive and dysmorphic side effects. Its disadvantages are its unavailability in parenteral formulation and its metabolic autoinduction. The latter must be compensated for by planned dosage increases to maintain therapeutic plasma steady-state levels during the first 2 or 3 months of treatment. Carbamazepine is judged a drug of choice in the treatment of these secondarily generalized tonic-clonic seizures, and the drug of choice in children, adolescents, and women susceptible to the dysmorphic side effects associated with other anticonvulsant agents.     

Etiologic and Preventive Aspects of Epilepsy in the Child–Bridging the Gap Between Laboratory and Clinic

Summary: Four broad categories of basic phenomena are pertinent to developing ways to prevent epilepsy. These include mechanisms of epileptogenesis, ictal initiation and temporary entrainment by the seizure discharge of normally functioning brain, seizure propagation, and control mechanisms that function both to restrain the cascade of epileptic events culminating in a seizure and to arrest the epileptic event and restore the interictal state. In newborns and children, hypoxia-ischemia is a major factor leading to epileptogenesis, and several schemes are proposed to classify, quantify, and prevent hypoxic-ischemic encephalopathy. Control mechanisms must be better understood in order to develop prophylactic recommendations for epilepsy, and an experimental model of "kindling antagonism" may increase our understanding of these. Programs of prevention of seizures in children will evolve only if basic researchers and clinicians work productively together to develop an adequate understanding of factors important in epileptogenesis and antiepileptogenic control mechanisms.     

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.     

Predisposing and Causative Factors in Childhood Epilepsy

Summary: We review information from large studies of defined populations, examining the role of known factors and especially of prenatal and perinatal factors in contributing to nonfebrile seizure disorders of early childhood. We depend especially, but not exclusively, on the recently completed analyses from the Collaborative Perinatal Project of the National Institute of Neurological and Communicative Disorders and Stroke, the NCPP. About 4% of children in the NCPP who had at least one non-febrile nonsymptomatic seizure by the age of 7 years had a previous seizure during acute neurologic illness, such as meningitis or during the acute illness after trauma. Many such seizures should potentially be preventable. Of children with seizures, 10% had had a neonatal seizure and 13% had had a febrile seizure. Among the hundreds of prenatal and perinatal factors explored as predictors of childhood seizure disorders, the principal predictors identified were congenital malformations of the fetus, cerebral and noncerebral; family history of certain neurologic disorders; and neonatal seizures. In agreement with the British National Child Development Study, labor and delivery factors in the NCPP appeared to contribute very little to childhood seizure disorders. Maldevelopment, rather than damage at birth to an initially intact nervous system, appeared to be the more common mechanism. Most seizure disorders of early childhood remained unexplained by the large set of prenatal and perinatal characteristics examined.     

Treatment Considerations in Anticonvulsant Monotherapy

Summary: The long-standing practice of polypharmacy in treating epilepsy is giving way to use of monotherapy. Monotherapy can improve seizure control as well as reduce the risk of serious idiosyncratic reactions, dose-related side effects, and complex drug interactions. Monotherapy also offers improved compliance and cost-effectiveness. The basis of monotherapy is accurate diagnosis and assessment of the patient's seizure type(s), followed by selection of a single appropriate anticonvulsant drug. Many patients currently treated with multiple anticonvulsants can be successfully converted to monotherapy with a carefully monitored program in which troublesome and redundant drugs are gradually withdrawn from the therapeutic regimen.     

Anticonvulsant Drugs and Cognitive Function: A Review of the Literature

Summary: Alterations of cognitive function are separate from disturbances of behavior seen in association with epilepsy. The nature of the cognitive disability may to a certain extent depend on the seizure type. Partial seizures, mainly derived from a temporal lobe focus, impair memory tasks, while generalized seizures seem to have more effect on attentional abilities. A number of studies, reviewed in this paper, suggest that anticonvulsant drugs further impair cognitive function. Maximal impairments are seen in patients receiving polytherapy: rationalization of polytherapy improves cognitive abilities. Studies in children and adults have allowed differentiation of the effects of various commonly used antiepileptic agents. Maximal cognitive deficits are seen with. phenytoin, while phenobarbital and sodium valproate induce moderate disturbances, and carbamazepine seems relatively free from such toxicity. Further research is needed on the interrelationship between types of seizure disorders, types of anticonvulsant medications, and cognitive function.     

Dextromethorphan: Cellular Effects Reducing Neuronal Hyperactivity

Summary: Dextromethorphan is a dextrorotary morphinan without affinity for opioid receptors, commonly used as an antitussive medication. During the past 5 years, interest in the compound and its demethylated derivative, dextrorphan, has been revived because additional neuroprotective and an-tiepileptic properties were found in in vitro studies, animal experiments, and a few clinical cases. Both morphinans are able to inhibit N -methyl-D-aspartate (NMDA) receptor channels and voltage-operated calcium and sodium channels with different potencies. The inhibition of the NMDA receptor is believed to be the predominant mechanism of action responsible for the anticonvulsant and neuroprotective properties of the compounds.