Neuropsychological And Cognitive Studies In Epilepsy

失控癫痫患者可能有与其癫痫发作相关的语言和记忆障碍。此外，当考虑手术时，绘制这些功能图是至关重要的。我们正在使用成像方法，努力取代更具侵入性的方法，以检测癫痫对语言和记忆的影响，并用于术前标测。方法：应用正电子发射断层扫描(PET)和功能磁共振成像(FMRI)对颞叶癫痫患者的语言和记忆功能进行无创性评估，研究癫痫对儿童和成人癫痫患者认知解剖学的影响。我们在正常志愿者和失控癫痫患者中的研究表明，成像评估与更具侵入性的程序，如电刺激标测和颈动脉内淀粉样钠试验相比，具有很好的可比性。我们还评估了癫痫发作对功能认知解剖学发展的影响。 我们以前的研究表明，不同的fMRI范式可以作为语言加工的不同方面的探针，视觉分析等同于感兴趣区的量化分析。我们检查了被认为有非典型语言的患者，发现fMRI显示了几种非典型语言处理模式，涉及左半球及其右半球的分布式网络。这些区域外的激活很少见，80%的非典型语言激活涉及某种形式的区域激活。我们还研究了与语言重组相关的因素，发现它们与早期癫痫发作、不典型利手和遥远原因有关。非损伤性新皮质癫痫患者语言不典型的发生率为30%，内侧颞叶硬化的发生率为23%，肿瘤和局灶性发育不良的发生率分别为14%。所有有左半球中风病史的患者都有某种形式的语言重组。 FMRI语言任务可以可靠地识别语言区域，但记忆范式一直存在问题。我们研究了一项海马区激活的听觉描述决策任务，并使用海马区掩蔽分析与25名患者的IAT进行了比较。我们发现，除了海马区是硬化区外，海马区的激活主要反映语言优势。我们发现与IAT偏侧指数的相关性很差，而基于IAT的优势HF激活与IAT记忆容量之间只有良好的相关性。 动脉自旋标记磁共振成像是一种可以直接测量脑血流量的新技术，它与间接血氧水平技术相反。这种方法可能对血流灌注限制不那么敏感，可提供更准确的数据，尤其是在儿童中。我们对患者和正常志愿者进行了研究，并将ASL与已建立的15-O水PET脑血流评估技术进行了比较。在GE Signa 3T磁共振扫描仪上进行PET检查，使用近端倒置和非共振效应对照(PICORE)-使用单一减影第二版(QUIPSS II)ASL序列进行定量灌注成像以估计基线流量。(TR/TE=2500ms/30ms，TI1/TI2=700ms/1400ms，FOV=24 cm，层厚7 mm，矩阵：64×64，轴位5层)。针对受试者的运动对图像进行了校正。血流值平均超过150个时间点，在每个颞叶。对于15O-PET，我们使用GE(美国威斯康星州沃基沙)先进断层扫描仪(FWHM=6-7 mm)，以4.25 mm的层间距扫描35个同步切片。扫描过程中，在一个安静昏暗的房间里，眼睛闭着，耳朵没有遮挡，一个热塑性口罩将受试者S的头固定在适当的位置。注射10mCI 15O-H2O，扫描2分钟，用自动血细胞计数器连续测量动脉血。在共同注册的结构MRI上绘制的区域获得定量的CBF值。与ASL-MRI比较，取海马结构、杏仁核、海马旁回和梭形回的局部脑血流量平均值。对于ASL-MRI和15O-PET，使用公式：2*(同侧-对侧)/(同侧+对侧)。我们的数据表明，使用QUIPSS II饱和脉冲的ASL-MRI可能是识别颞叶致痫区域的有用工具，提供了与15O-PET相当的CBF数据。 当前研究：在建立和验证成人ASL后，我们正在进行3T动脉自旋标记的fMRI休息和激活研究，该研究将检查脑血流和BOLD信号反应的发育差异。我们还计划研究颞叶切除术对语言和工作记忆的功能解剖的影响。最近的证据表明，前极和杏仁核在这些分布式神经系统中起着中心作用。我们将研究前颞叶结构在调节涉及语义和情感加工的记忆网络中的作用。使用功能磁共振成像，将评估颞叶癫痫(TLE)患者在前颞叶切除术前后的行为结果以及fMRI激活模式，并将其与年龄、性别和教育匹配的健康对照组进行比较。对有计划的手术损伤对人类皮质网络的影响的研究有可能对记忆回路的特征做出重大贡献，并可以形成为社会和认知功能障碍患者开发新的治疗策略的基础。

Patients with uncontrolled epilepsy may have impairment of language and memory associated with their seizures. In addition, it is critical to map these functions when surgery is being considered. We are using imaging methods in an effort to replace more invasive approaches to detecting the effects of epilepsy on language and memory, and for preoperative mapping. Methods: We use positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) to map language and memory in patients with temporal lobe epilepsy to perform non-invasive evaluation of functional cortex, and study the effect of epilepsy on cognitive anatomy in children and adults with seizures. Our studies in both normal volunteers and patients with uncontrolled seizures have shown that imaging evaluation compares well with more invasive procedures such as electrostimulation mapping and the intra-carotid sodium amytal test. We also evaluate the effect of seizures on the development of functional cognitive anatomy. Our previous studies have demonstrated that different fMRI paradigms may be used as probes of different aspects of language processing and that visual analysis is equivalent to quanitative region of interest analysis. We have examined patients deemed to have atypical language and find that fMRI demonstrates several patterns of atypical language processing that involve a distributed network in the left hemisphere and its right homologues. Activation outside there areas is rare, 80% of atypical language activation involves some form of regional activation. We have also examined the factors associated with language re-organization and find them associated with early age seizure onset, atypical handedness and remote cause. Patients with non-lesional neocortical epilepsy have a 30% incidence of atypical language, mesial temporal sclerosis 23%, tumor and focal dysplasia 14% each. All patients with a history of left hemisphere stroke have some form of language reorganization. fMRI language tasks reliably identify language areas but memory paradigms have been problematic. We examined an auditory description decision task for hippocampal activation and compared to IAT in 25 patients using a hippocampal mask analysis. We found that activation in hippocampus mostly reflected language dominance except where the hippocampus was sclerotic. We found poor correlation with IAT laterality indices, and only fair correlation between dominant HF activation and IAT memory capacity based on IAT. Arterial spin-labeled MRI is a new techniques that allows direct measurement of cerebral blood flow, as oppsoed to the indirect blood oxygenation level technique. this approqch may be less sensitive to perfusion limitations, nad provide more accurate data, particulalry in children. We have bene studying patients and normal volunteers in a comparions of ASL with the established 15-O water PET technique for cerebral blood flow estimation. PET was performed on a GE Signa 3T MRI scanner using a proximal inversion with a control for off resonance effects (PICORE)- quantitative imaging of perfusion using a single subtraction, second version (QUIPSS II) ASL sequence to estimate baseline flow. (TR/TE = 2500ms/30ms, TI1/TI2 = 700ms/1400ms, FOV = 24cm, slice thickness = 7mm, matrix: 64x64, 5 axial slices). Images were corrected for subject motion. Flow values were averaged over 150 time points, in each temporal lobe. For 15O-PET, we used a GE (Waukesha, WI, USA) Advance Tomograph (FWHM = 6-7 mm), scanning 35 simultaneous slices with 4.25 mm slice separation. During scanning, in a quiet, dim room with eyes closed and ears unoccluded, a thermoplastic facemask held the subject s head in place. 10 mCi 15O-H2O was injected, and scanning performed for two minutes, using continuous arterial blood measurements with an automatic blood counter. Quantitative CBF values were obtained in regions drawn on co-registered structural MRI. For comparison with ASL-MRI, regional CBF from hippocampal formation, amygdala, parahippocampal gyrus, and fusiform gyrus were averaged. For both ASL-MRI and 15O-PET, an asymmetry index (AI) was derived using the formula: 2 * (ipsilateral-contralateral)/ (ipsilateral+contralateral).Our data suggest that ASL-MRI using QUIPSS II saturated pulse may be a useful tool for identifying temporal lobe epileptogenic zones, providing CBF data comparable to 15O-PET. Current Studies: After establishing and validation ASL with PET in adults we are embarking on fMRI rest and activation studies using arterial spin tagging at 3T that will examine developmental differences in cerebral blood flow and BOLD signal response. We also plan to study the effects of temporal lobectomy on the functional anatomy of language and working memory. Recent evidence suggests a central role for the anterior pole and the amygdala in these distributed neural systems. We will stuyd the role of anterior temporal lobe structures in modulating memory networks involved in semantic and affective processing. Using fMRI, patients with temporal lobe epilepsy (TLE) will be evaluated before and after anterior temporal lobectomy and behavioral results as well as fMRI activation patterns will be compared to those of age-,sex- and education-matched healthy controls. The study of the effects of a planned surgical lesion on cortical networks in humans has the potential to significantly contribute to the characterization of memory circuitry and can form the basis for the development of novel treatment strategies for patients with social and cognitive dysfunctions.