Functional Magnetic Resonance Imaging of Language in Epilepsy

Functional magnetic resonance imaging (fMRI) has revolutionized our understanding of functional networks and cerebral organization in both normal and pathological brains. In the present review, we describe the use of fMRI for mapping language in epilepsy patients prior to surgical intervention including a discussion of methodological issues and task design, comparisons between fMRI and the intracarotid sodium amobarbital test, fMRI studies of language reorganization, and the use of fMRI laterality indexes to predict outcome after anterior temporal lobectomy.     

Language Development in Children with Simple-Partial Left-Hemisphere Epilepsy

The nature of cerebral involvement in the acquisition of language was addressed in this longitudinal study of children with an early diagnosis of epilepsy with simple-partial seizures (SPE) and with epileptogenic foci localized in the left frontal (LF) lobe. Yearly evaluations of six SPE-LF children on tests of linguistic comprehension (pointing, understanding of narrative, and understanding of prepositions) and production (repetition, lexical diversity, and grammatical production) were carried out between the ages of 3 and 8 years and compared to those of large samples of control children on the same tasks and at each age level. Linguistic production of all children were transcribed, coded, and analyzed using the Child Language Data Exchange System (MacWhinney & Snow, 1991). Individual evolution trajectories revealed that SPE-LF children showed a clear dissociation in linguistic performance between comprehension and production. Linguistic comprehension gradually improved to reach normal performance levels by age 7 while linguistic production, even at later stages, remained quite poor. This dissociation in the development of linguistic performance in SPE-LF children suggests a complex interplay between brain maturation dynamics and dysfunction modulating the succession of stages in language development. The observed persistent deficits in specific aspects of linguistic performance argue for an early involvement of the anterior areas of the left cerebral hemisphere in the production of language.     

Cortical Language Mapping in Epilepsy: A Critical Review

One challenge in dominant hemisphere epilepsy surgery is to remove sufficient epileptogenic tissue to achieve seizure freedom without compromising postoperative language function. Electrical stimulation mapping (ESM) of language was developed specifically to identify essential language cortex in pharmacologically intractable epilepsy patients undergoing left hemisphere resection of epileptogenic cortex. Surprisingly, the procedure remains unstandardized, and limited data support its clinical validity. Nevertheless, ESM for language mapping has likely minimized postoperative language decline in numerous patients, and has generated a wealth of data elucidating brain–language relations. This article reviews the literature on topographical patterns of language organization inferred from ESM, and the influence of patient characteristics on these patterns, including baseline ability level, age, gender, pathology, degree of language lateralization and bilingualism. Questions regarding clinical validity and limitations of ESM are discussed. Finally, recommendations for clinical practice are presented, and theoretical questions regarding ESM and the findings it has generated are considered.     

早期双语儿童第二语言的词汇概念组织

该文通过两个实验考察早期双语儿童第二语言的词汇概念组织。实验1运用跨语言重复启动的范式,结果发现了跨语言重复启动效应,说明早期双语儿童可以直接通达概念意义,但是二语词汇语义通达的强度要弱于一语词汇语义通达的强度。在实验1的基础上,实验2运用图片命名的范式,结果发现了命名的语言效应,进一步说明早期双语儿童二语词汇与概念表征的联系要弱于一语词汇与概念表征的联系。总的实验结果表明,早期双语儿童在记忆表征中建立了二语词汇与概念表征的直接联系,其第二语言的词汇概念组织在本质上是机能性的。     

盲人的跨感觉通道重组

失去视觉的盲人往往伴随着行为代偿,如听觉和触觉能力的提高。脑成像等认知神经科学研究发现,盲人行为代偿的神经机制之一是大脑皮层的跨感觉通道重组,即盲人的视皮层并没有因为视觉剥夺而失去作用,而是广泛地参与了其他感知觉任务。原本暂时的神经联结由于受到新的感觉信息传入方式的持续激活而固化,从而形成新的神经回路,可能是此类跨通道重组的神经基础。     

Brain Organization of Language after Early Unilateral Lesion: A PET Study

Neuropsychological studies suggest that good long-term language outcome is possible following extensive early left-hemisphere damage. We explored the brain organization for language in children with early unilateral lesion, using [¹⁵O]-water PET. In 12 patients with left lesion (LL) and 9 patients with right lesion (RL), cerebral blood flow changes during listening to sentences and repetition were studied. A rightward shift of language activations in the LL group was found in perisylvian areas and multiple other, mostly temporo-parietal, regions. The hypothesis of intrahemispheric reorganization in the LL group found only limited support. The number of activated regions was overall greater in the RL group. Unexpected findings included a stronger subcortical and cerebellar language involvement in the RL group. We suggest that (a) early left lesion is associated with enhanced language participation of the right hemisphere in and beyond the classical language areas, and (b) postlesional effects are in part additive (recruitment of noncanonical areas), in part subtractive (functional depression in areas normally involved in language).     

Epilepsy and suicide

Although statistics dealing with the causes of death are often difficult to compare, in some cases they indicate that suicide rates are high among people suffering from seizures. The author considers this critically. At present the number of attempted suicides among this group is at least five times higher than among the average population. The author reports on his own findings, on factors indicating potential suicide victims, and on the possible prevention of suicide, particularly in connection with pharmaceutical treatment.     

Cognitive Progression in Epilepsy

The issue of cognitive progression in people with epilepsy is of considerable interest and has important clinical and theoretical implications. In this paper, we review recent studies in both the adult and childhood epilepsy literature which have included a longitudinal test–retest design to examine this question. Several important methodological issues of this literature are highlighted and areas which require more investigation are identified.     

语言经验可以改变双语者的主导语言

使用语义启动词汇判断范式,研究维吾尔语-汉语和朝鲜语-汉语大学生双语者词汇加工的模式如何受语言经验的影响.实验一表明,维汉双语者既存在语言内、也存在语言间的语义启动效应.不管目标词是维吾尔语还是汉语,以维吾尔语(母语)为启动词的效应要大于以汉语为启动词的效应.实验二表明,朝汉双语者语言内产生了类似大小的效应;但当目标词是汉语、启动词是朝鲜语时,却没有启动效应.进一步的问卷调查表明,朝汉双语被试虽在小学和中学阶段听说和阅读母语的概率大于听说和阅读汉语,但在大学阶段却是汉语占优势;维汉双语被试在小学、中学、大学时的口头语言都是母语占优势;虽然他们在大学阶段阅读汉语的概率要大于母语,但两者的差异要明显小于朝汉双语被试.这些结果说明,语言经验可以改变词汇形式表征的加工速率以及从形式表征出发激活词汇意义的模式,从而使得第二语言有可能取代母语而上升为主导语言.     

癫痫的诊治与人文思想

癫痫是神经科常见的疾病之一,时于患者的学习、生活和工作均有不同程度影响.它的发病机制尚不十分清楚,主要是以药物治疗为主.在癫痫的诊断中要根据病情和忠者的实际情况选择合适的检查;在癫痫的治疗中须按照最优化的医疗原则选择最佳的治疗方案.在治疗中要注意结合人文思想来提高癫痫的治疗效果.     

癫痫的诊治与人文思想

癫痫是神经科常见的疾病之一,对于患者的学习、生活和工作均有不同程度影响。它的发病机制尚不十分清楚,主要是以药物治疗为主。在癫痫的诊断中要根据病情和患者的实际情况选择合适的检查;在癫痫的治疗中须按照最优化的医疗原则选择最佳的治疗方案。在治疗中要注意结合人文思想来提高癫痫的治疗效果。     

Cognitive Reorganization and the development of chess expertise

One current research strategy in the study of expertise is to compare experts and novices. An important aspect of decision making involves looking for similarities among problem types. Little is known about such processes. We used grid technique to examine similarity judgments associated with different levels of chess expertise. Novice, expert, and master chess players evaluated 4 sets of 12 chess boards. Average FIC scores showed a curvilinear relation to expertise, suggesting increasing differentiation followed by integration in cognitive frameworks for construing board positions. Additional cognitive measures based on move generation tended to support and extend this structural model.     

Epilepsy and pregnancy--principles of therapy

Special aspects of antiepileptic therapy during pregnancy in epileptic women are described. A monotherapy should be preferred. Due to changes in the pharmacokinetics of antiepileptic drugs, plasma level checks must be performed every four weeks during early pregnancy. The possible teratogenetic effects of anticonvulsants and other factors tending to increase of malformation rate are discussed. An explanation is given for the use of prophylactic folic acid and Vitamin K treatment in connection with antiepileptic therapy. The benefits of counselling prior to pregnancy are discussed.     

Epilepsy, consciousness and neurostimulation

Consciousness is often disrupted in epilepsy. This may involve altered responsiveness or changes in awareness of self and subjective experiences. Subcortical arousal systems and paralimbic fronto-parietal association cortices are thought to underpin current concepts of consciousness. The Network Inhibition Hypothesis proposes a common neuroanatomical substrate for impaired consciousness during absence, complex partial and tonic-clonic seizures. Neurostimulation in epilepsy remains in its infancy with vagal nerve stimulation (VNS) as the only firmly established technique and a series of other methods under investigation including deep brain stimulation (DBS), intracranial cortical stimulation and repetitive transcranial magnetic stimulation (rTMS). Many of these systems impact on the neural systems thought to be involved in consciousness as a continuous duty cycle although some adaptive (seizure triggered) techniques have been developed. Theoretically, fixed duty cycle neurostimulation could have profound effects on responsiveness, awareness of self and subjective experience. Animal studies suggest vagal nerve stimulation positively influences hippocampal long term potentiation. In humans, a chronic effect of increased alertness in VNS implanted subjects and acute effect on memory consolidation have been reported but convincing data on either improvements or deterioration in attention and memory is lacking. Thalamic deep brain stimulation (DBS) is perhaps the most interesting neurostimulation technique in the context of consciousness. Neither bilateral anterior or centromedian thalamic nucleus DBS seem to affect cognition. Unilateral globus pallidus internus DBS caused transient wakefulness in an anaesthetised individual. As intracranial neurostimulation, particularly thalamic DBS, becomes more established as a clinical intervention, the effects on consciousness and cognition with variations in stimulus parameters will need to be studied to understand whether these secondary effects of neurostimulation make a significant positive (or adverse) contribution to quality of life.     

Organization in memory and behavior

Some common reinforcement contingencies make the delivery of a reinforcer depend on the occurrence of behavior lacking significant temporal structure: a reinforcer may be contingent on nearly instantaneous responses such as a pigeon's key peck, a rat's lever press, a human's button press or brief verbal utterance, and so on. Such a reinforcement contingency conforms much more closely to the functionalist tradition in experimental psychology than to the structuralist tradition. Until recently, the functionalist tradition, in the form of a kind of associationism, typified most research on human learning and memory. Recently, however, research on human memory has focused more on structural issues: now the basic unit of analysis often involves an organized temporal pattern of behavior. A focus on the interrelations between the function and structure of behavior identifies a set of independent and dependent variables different from those identified by certain common kinds of “molar” behavioral analyses. In so doing, such a focus redefines some of the significant issues in the experimental analysis of behavior.     

Epilepsy and pregnancy--results of interdisciplinary cooperation

A total of 19 female epileptics were jointly counselled, cared for and delivered during 21 pregnancies. Special aspects that must be taken into account during pregnancy in epileptics are described. Due to changes in the pharmacokinetics of anti-epileptic drugs, plasma level checks must be performed every four weeks during early pregnancy. The possible teratogenic effects of anticonvulsants and other factors tending to increase the malformation rate are discussed. An explanation is given for the use of prophylactic folic acid and vitamin k treatment in connection with anti-epileptic therapy. Breast feeding has not only proved advantageous from the nutritional standpoint but also helps withdraw the new-born, who is habituated to anticonvulsants, from the drugs without negative symptoms. The benefits of counselling prior to pregnancy and general questions relating to women who are prone to seizures while they are of child-bearing age is discussed.     

Neuropsychological Deficits in Childhood Epilepsy Syndromes

Seizure disorders are relatively common in childhood, and the International League Against Epilepsy (ILAE) provides a hierarchical classification system to define seizure types. At the final level of classification, specific epilepsy syndromes are defined that represent a complex of signs and symptoms unique to an epilepsy condition. The present review discusses the issues related to several of these epilepsy syndromes in childhood, including those classified as generalized idiopathic epilepsies (e.g., childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy), focal epilepsies (benign rolandic epilepsy, occipital epilepsy, temporal lobe epilepsy, frontal lobe epilepsy) and the "epileptic encephalopathies," including Dravet's Syndrome, West Syndrome, Lennox-Gastaut Syndrome, Myoclonic Astatic Epilepsy, and Landau-Kleffner Syndrome. For each syndrome, the epidemiology, clinical manifestations, treatments, and neuropsychological findings are discussed.