大脑中动脉粥样硬化斑块的影像学特征

目的应用高分辨率磁共振(HR-MRI)管壁成像技术比较症状性与无症状性大脑中动脉(MCA)粥样硬化斑块的影像学特征。方法根据MCA支配区是否有急性脑梗死或TIA,将116例有MCA粥样硬化狭窄的患者分为症状组80例及无症状组36例。采用3.0 T HR-MRI检查MCA斑块影像学特征。结果症状组患者环形斑块比率明显高于无症状组(P=0.019)。症状组和无症状组斑块信号类型在T_1WI、T_2WI和STIR上差异无统计学意义(均P0.05)。与无症状组比较,症状组斑块明显强化比率显著升高(P0.001),无强化及轻度强化比率显著降低(均P0.001)。结论 HR-MRI可以清晰显示MCA粥样硬化斑块形态。症状性MCA斑块以环形多见,斑块明显强化;非症状性MCA斑块以弧形为主,斑块多无强化或轻中度强化。两组斑块信号在各序列无明显差异。     

ADAMTS基因多态性与脑梗死体检患者颈动脉粥样硬化性斑块易损性及阿托伐他汀降脂疗效的相关性研究

目的 探讨Ⅰ型血小板结合蛋白基序的解聚蛋白样金属蛋白酶（a disintegrin and metalloproteinase with thrombospondin type 1 motifs，ADAMTS）基因多态性与脑梗死体检患者颈动脉粥样硬化性斑块易损性及阿托伐他汀降脂疗效的相关性。方法 收集2016年1月至2019年1月河北医科大学第一医院收治的684例脑梗死体检患者的临床资料，根据颈动脉超声检查结果分为稳定斑块组（338例）和易损斑块组（346例）。比较2组患者的一般资料、生化检测指标、ADAMTS rs402007（G/C）位点基因型及等位基因频率。采用Logistic回归分析探讨颈动脉粥样硬化性斑块易损性的危险因素和ADAMTS基因多态性与危险因素在颈动脉粥样硬化性斑块易损性中的交互作用。比较不同基因型患者阿托伐他汀降脂疗效，分析不同基因型与阿托伐他汀疗效的相关性。结果 稳定斑块组和易损斑块组糖尿病比例及低密度脂蛋白胆固醇（low-density lipoprotein cholesterol，LDL-C）、总胆固醇（total cholesterol，TC）、同型半胱氨酸（homocysteine，HCY）、纤维蛋白原（fibrinogen，FIB）水平的比较差异有统计学意义（P<0.05）。2组患者间GG基因型与GC+CC基因型分布的比较差异有统计学意义（P<0.05）。糖尿病、LDL-C、HCY、FIB是影响颈动脉粥样硬化性斑块易损性的危险因素（P<0.05）。LDL-C与ADAMTS基因rs402007位点存在交互作用（P<0.05）。GG、GC、CC基因型组阿托伐他汀降脂治疗有效率分别为144例（82.29%）、209例（84.27%）、233例（89.27%）。各基因型患者阿托伐他汀治疗前后血脂水平比较差异有统计学意义（P<0.05）。稳定斑块组和易损斑块组治疗前、治疗后LDL-C水平，以及治疗后高密度脂蛋白胆固醇、甘油三酯、TC水平比较差异有统计学意义（P<0.05）。以GG基因型为参考，GC基因型与阿托伐他汀治疗的疗效无相关性（P>0.05），CC基因型与疗效有相关性（P<0.05）。结论 ADAMTS基因多态性与颈动脉粥样硬化性斑块易损性存在相关性，与阿托伐他汀的降脂疗效存在相关。     

老年急性缺血性脑卒中患者颈动脉斑块检出率及其与脑卒中复发的相关性

目的 应用多普勒彩色超声诊断仪评估老年急性缺血性脑卒中（AIS）患者颈动脉斑块检出情况,总结斑块发生的高危因素,并分析其与AIS复发的相关性。方法 以2020年1月至2020年6月于常州市第一人民医院神经内科和老年医学科住院的首次发生AIS,并且72 h内入院的老年患者236例为研究对象。依据颈动脉超声检查结果分为颈动脉斑块组（199例）和无颈动脉斑块组（37例）。收集并分析2组患者的临床资料及随访1.5年后脑卒中复发情况。结果 老年AIS患者颈动脉斑块检出率为84.3%。60~69岁、70~79岁及≥80岁患者颈动脉斑块检出率分别为74.7%、86.9%、96.0%,随着年龄增长颈动脉斑块检出率逐渐增加。颈动脉斑块组女性、高血压史和糖尿病史的比例明显高于无斑块组（均P<0.05）。颈动脉斑块组与无颈动脉斑块组脑卒中复发事件发生率比较,差异有统计学意义（P<0.05）。多因素Logistic回归分析结果显示,年龄（OR=1.070,95%CI：1.02~1.122,P=0.005）、糖尿病史（OR=2.262,95%CI：1.055~4.850,P=0.036）、颈动脉斑块（OR=8.128,95%CI：1.077~61.348,P=0.042）是AIS复发的独立影响因素。结论 老年AIS患者颈动脉斑块检出率高。年龄、性别、高血压史、糖尿病史是颈动脉粥样硬化的危险因素。年龄、糖尿病史、颈动脉斑块与脑卒中复发事件发生相关。     

血清可溶性CD40配体与急性脑梗死患者颈动脉斑块的关系

目的 探讨血清可溶性CD40配体（sCD40L）水平与急性脑梗死患者颈动脉粥样硬化斑块的关系。方法 选取2018年5月至2019年5月在中国医科大学附属盛京医院神经内科住院的急性脑梗死患者108例。根据颈部动脉超声结果分为无斑块组和斑块组，斑块组根据斑块性质进一步分为稳定斑块组和不稳定斑块组。应用酶联免疫吸附法（ELISA）测定血清sCD40L水平；分析血清sCD40L水平与颈动脉粥样硬化斑块的关系。结果 颈动脉斑块组患者高血压（P=0.026）、空腹血糖（P=0.045）、三酰甘油（P=0.027）、低密度脂蛋白胆固醇（LDL-c）（P=0.005）和sCD40L水平（P<0.001）均高于无斑块组。高血压（OR=2.598，P=0.028）、LDL-C（OR=4.247，P=0.006）和sCD40L水平（OR=1.079，P=0.009）是急性脑梗死患者存在颈动脉粥样硬化斑块的危险因素。颈动脉不稳定斑块组患者高血压（P=0.031）、白细胞计数（P=0.002）、低密度脂蛋白胆固醇（P=0.003）和sCD40L水平（P<0.001）均高于稳定斑块组。不稳定颈动脉斑块组患者，高血压（OR=2.918，P=0.033）和sCD40L水平（OR=2.712，P<0.001）是急性脑梗死患者颈动脉斑块不稳定性的危险因素。结论 急性脑梗死患者血清sCD40L水平的升高与颈动脉粥样硬化斑块的发生和发展相关，亦与颈动脉斑块的不稳定性相关。     

Neuroform EZ支架置入对症状性大脑中动脉重度狭窄患者脑血流灌注、血管内皮功能、认知功能及神经功能缺损的干预效果

目的 探讨Neuroform EZ支架置入辅助治疗症状性大脑中动脉重度狭窄的临床效果。方法 回顾性分析2016年10月至2019年10月该院症状性大脑中动脉重度狭窄患者85例临床资料,按治疗方案不同分为观察组（43例）、对照组（42例）。对照组予以单纯药物治疗,观察组在药物治疗基础上联合Neuroform EZ支架置入术。比较两组术后1年疗效、不良事件发生情况;比较两组及术前、术后6个月、术后1年认知功能评分(MMSE)、神经功能缺损程度评分(NIHSS)、脑血流灌注指标［脑血流量(CBF)、脑血容量(CBV)］、血管内皮功能指标［一氧化氮(NO)、内皮素(ET)］。结果 观察组术后1年总有效率为95.35%,高于对照组78.57%,差异有统计学意义(P<0.05)。两组术后6个月、1年MMSE评分及CBF、CBV、NO水平较术前提高,且观察组高于对照组,差异有统计学意义(P<0.05)。NIHSS评分及ET水平较术前降低,且观察组低于对照组,差异有统计学意义(P<0.05)。观察组不良事件发生率为13.95%,低于对照组33.33%,差异有统计学意义(P<0.05)。结论 Neuroform EZ支架置入辅助治疗症状性大脑中动脉重度狭窄可促进认知与神经功能改善,且在改善脑血流灌注、血管内皮功能、减少不良事件方面具有积极作用。     

甘油三酯-葡萄糖指数对脑梗死患者脑血管狭窄程度的预测价值

目的 探讨甘油三酯-葡萄糖指数对脑梗死患者脑血管狭窄程度的预测价值。方法 选择2022年10月至2023年5月在菏泽市立医院神经内科住院的脑梗死患者357例作为研究对象。根据脑血管狭窄程度分为2组：正常或轻度狭窄组（195例,狭窄<50%）和中重度狭窄组（162例,狭窄≥50%）。采用多因素Logistic回归分析模型分析脑血管中重度狭窄的危险因素。根据受试者操作特征（ROC）曲线评估甘油三酯-葡萄糖指数对脑梗死患者脑血管狭窄程度的预测价值。结果 中重度狭窄组患者的年龄、空腹血糖、甘油三酯、甘油三酯-葡萄糖指数、总胆固醇、低密度脂蛋白胆固醇高于正常或轻度狭窄组（P<0.05）。多因素Logistic回归分析显示,年龄、空腹血糖、甘油三酯-葡萄糖指数是脑梗死患者脑血管中重度狭窄的危险因素（P<0.05）。ROC曲线分析显示,甘油三酯-葡萄糖指数预测脑梗死患者脑血管中重度狭窄的最佳截断值为8.59（P<0.01）,灵敏度为0.685,特异度为0.549。结论 甘油三酯-葡萄糖指数与脑梗死患者的脑血管狭窄程度相关,并对中重度狭窄具有一定的预测价值。     

弥散加权成像阴性脑梗死患者大血管狭窄或闭塞发生率的研究

目的 阐明弥散加权成像(DWI)阴性脑梗死患者大血管狭窄或闭塞发生率。 方法 选择在该院神经内科住院的DWI阴性脑梗死患者（DWI阴性组,46例）;DWI阳性脑梗死患者（DWI阳性组,357例）。记录两组患者的临床资料和血液学检验结果、头颅磁共振血管成像(MRA)检查结果。 结果 与DWI阳性组患者相比,DWI阴性组患者表现为偏身运动障碍的比例高,高级皮质功能障碍的比例高,失语的比例低,差异均有统计学意义( P<0.05)。DWI阴性组和DWI阳性组D ₁、D ₇、D ₁₄的美国国立卫生研究院卒中量表(NIHSS)评分和改良Rankin量表(mRS)评分比较,差异无统计学意义( P>0.05)。DWI阴性组的甘油三酯和叶酸水平低于DWI阳性组,差异均有统计学意义( P<0.05)。DWI阴性组的大脑前动脉、颈内动脉(C ₂～C ₇段)、大脑后动脉狭窄或闭塞的比例低于DWI阳性组脑梗死患者,差异均有统计学意义( P<0.05)。DWI阴性组颅内狭窄或闭塞的动脉总数与DWI阳性组患者相比,差异无统计学意义( P>0.05)。DWI阴性组颈总动脉+颈内动脉(C ₁段)、椎动脉(V ₁～V ₂段)、颅外狭窄或闭塞的血管总数与DWI阳性组患者相比,差异均无统计学意义( P>0.05)。 结论 DWI阴性脑梗死患者发生颅内、颅外大血管狭窄或者闭塞的概率可能并不低于DWI阳性脑梗死患者。     

虚拟现实技术结合肢体协调辅助装置训练对缺血性脑卒中患者脑灰质含量及肢体运动功能的影响

目的 探讨虚拟现实（VR）技术结合肢体协调辅助装置训练对缺血性脑卒中患者脑灰质含量、运动功能、认知功能和日常生活能力的影响。方法 选取2022年2月至2023年1月合肥市第二人民医院收治的122例缺血性脑卒中患者作为研究对象，按照随机数字表法分为对照组（61例）和观察组（61例），其中对照组患者采取肢体协调辅助装置训练，观察组采取VR结合肢体协调辅助装置训练，治疗周期为2个月。对比治疗前后2组患者睁眼1 min轨迹面积、睁眼1 min摆动长度、上下肢运动功能、神经功能、认知功能和日常生活能力。结果 治疗后2组的睁眼1 min轨迹面积、睁眼1 min摆动长度均较治疗前显著减少（P<0.05），且观察组的轨迹面积和摆动长度均小于对照组（P<0.05）。治疗后2组的上下肢运动评分、脑灰质含量、蒙特利尔认知评估量表（MoCA）评分和日常生活能力均较治疗前显著提高（P<0.05），且观察组的这些指标水平均高于对照组（P<0.05）。治疗后神经功能评分均较治疗前显著降低（P<0.05），且观察组的该评分低于对照组（P<0.05）。结论 VR结合肢体协调辅助装置训练可有效促进缺血性脑卒中患者平衡功能的恢复，提高患者肢体运动功能，改善患者神经功能、认知功能和日常生活能力。 [国际神经病学神经外科学杂志, 2023, 50(6): 19-23]     

经颅磁刺激联合艾司西酞普兰对良性阵发性位置性眩晕患者伴焦虑的疗效

目的 观察经颅磁刺激对良性阵发性位置性眩晕(BPPV)患者伴焦虑的治疗作用。方法 BPPV合并焦虑的患者168例,随机分为对照组和联合组,每组各84例。2组均给予艾司西酞普兰联合倍他司汀治疗,联合组在此基础上给予经颅磁刺激,均治疗4周。于治疗前、后,采用汉密尔顿焦虑量表(HAMA)评价患者焦虑程度,眩晕障碍量表(DHI)评价眩晕程度。比较2组疗效。结果 治疗后,联合组与对照组的HAMA评分均较治疗前明显降低,差异有统计学意义(P<0.05),且联合组低于对照组,差异有统计学意义(P<0.05);联合组的治疗有效率为81%,对照组的治疗有效率为68%,联合组的治疗有效率高于对照组。治疗后,联合组与对照组的DHI评分均较治疗前明显降低(P<0.05),且联合组低于对照组(P<0.05);联合组的有效率为83%,对照组的有效率为66%,联合组的有效率高于对照组。结论 经颅磁刺激联合艾司西酞普兰及倍他司汀能有效改善BPPV患者的焦虑症状,疗效高于艾司西酞普兰联合倍他司汀治疗。     

老年白内障患者合并抑郁状况及其自我感受负担的影响

背景 伴抑郁症状的老年白内障患者自我感受负担较重,术后视觉相关生活质量较无抑郁症状的患者更差,家庭负担更重。既往研究多认为家庭关系、视力等是导致老年白内障患者出现抑郁症状的主要因素,自我感受、合并疾病等对老年白内障患者心理状态的影响研究有限。目的 探讨老年白内障患者抑郁症状与自我感受负担和术后视觉相关生活质量的关系,分析患者抑郁症状的危险因素,对其进行针对性的心理干预提供参考。方法 连续纳入2020年7月1日—2022年12月31日在江苏省人民医院（南京医科大学第一附属医院）住院治疗的老年白内障患者104例,采用自编调查问卷收集患者基本资料,采用患者健康问卷抑郁量表（PHQ-9）、自我感受负担量表（SPBS）、25项美国国家眼科研究所视功能问卷（NEI-VFQ-25）评定患者抑郁症状、自我感受负担以及术后视觉相关生活质量水平。采用Pearson相关分析考查伴抑郁症状的老年白内障患者PHQ-9、SPBS、NEI-VFQ-25评分的相关性,采用Logistic回归分析老年白内障患者抑郁症状的影响因素。结果 共100例老年白内障患者完成有效问卷调查,检出31例（31.00%）患者存在抑郁症状。抑郁组SPBS评分高于无抑郁组（t=11.062,P<0.01）,NEI-VFQ-25评分低于无抑郁组（t=-5.235,P<0.01）。Pearson相关分析结果显示,伴抑郁症状的老年白内障患者PHQ-9评分与SPBS评分呈正相关（r=0.485,P<0.01）,与NEI-VFQ-25评分呈负相关（r=-0.440,P<0.01）。合并糖尿病（OR=1.441,P<0.01）、合并骨关节炎（OR=1.324,P<0.05）和高SPBS评分（OR=1.340,P<0.05）是老年白内障患者出现抑郁症状的危险因素。结论 老年白内障患者抑郁症状检出率较高;伴抑郁症状的老年白内障患者术后视觉相关生活质量更低;合并糖尿病、骨关节炎以及自我感受负担较重是老年白内障患者出现抑郁症状的危险因素。     

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.     

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.     

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.     

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.     

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.     

Effects of NMD A- and AMPA-Receptor Antagonists on Different Forms of Epileptiform Activity in Rat Temporal Cortex Slices

Summary: Lowering extracellular magnesium induces different patterns of epileptiform activity in rat hippocampus and entorhinal cortex. Short recurrent epileptiform discharges in the hippocampus are stable over time, whereas seizurelike events (SLEs) in the entorhinal cortex, the subiculum, and the neighboring neocortex develop into late recurrent discharges which are not blocked by clinically employed antiepileptic drugs. We tested the sensitivity of the different epileptiform discharge patterns to. /V-methyl-D-aspartate (NMDA)- and non-NMDA-receptor antagonists. As NMDA-receptor antagonist we used dextrorphan, ket-amine, and 2-aminophosphonovalerate (2APV); as α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA)-receptor antagonist we employed the quinoxaline derivative glutamate 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). The findings show that the different patterns of epileptiform activity, including the late recurrent discharges, are sensitive to all NMDA-receptor antagonists. However, when dextrorphan was employed to suppress seizure-like events, later recurrent discharges did not develop during the remaining time course of the experiment. CNQX reversibly suppressed recurrent discharges in the hippocampus and SLEs in the entorhinal cortex. However, late recurrent discharges become insensitive to CNQX, even at a high concentration of 60 μM m. This finding suggests a prominent role for NMDA receptors in the generation of late recurrent discharges.