脑深部电刺激治疗运动障碍性疾病

随着神经影像学、神经生理学和生物工程的发展，使运动障碍性疾病的外科疗效有明显提高，近几年来脑深部电刺激(deep brain stimulation，DBS)是治疗运动障碍性疾病的有效方法，具有效果明显，手术安全，并发症低等优点，DBS在运动障碍性疾病手术中除合理选择颅内靶点外，手术后的DBS程控调节是治疗帕金森病的重要环节，     

深部电刺激脑内靶点在帕金森病中的应用

本综述脑深部电剌激(DBS)治疗帕金森病常用靶点的临床应用，目前常用靶点包括丘脑腹中间核(Vim)，苍白球内侧(GHi)和丘脑底核(STN)，根据病人症状可选择不同靶点。Vim DBS对单纯震颤的帕金森病有显疗效，GPi DBS和STN DBS适用于既有震颤和僵硬的帕金森病病人，又适用于运动迟缓和异动症病人，术后可逐渐减少服用多巴胺的剂量。目前认为STN DBS缓解震颤和僵硬疗效要优于GPi和Vim DBS，研究表明STN DBS具有一定的神经保护作用，它抑制了STN的过度兴奋，使谷氨酸的释放减少，降低对投射区域的神经毒性作用，减少了多巴胺能神经元的变性，延缓帕金森病的进展，可作为DBS治疗帕金森病的首选靶点。     

脑深部电刺激治疗帕金森病的研究进展

脑深部电刺激(Deep Brain Stimulation,DBS)是目前治疗帕金森病(PD)的一种有效方法,具有效果明显、手术安全、并发症少等优点,DBS在PD手术中除合理选择颅内靶点外,手术后的DBS程控调节是治疗PD的重要环节,其临床疗效与术后程控调节有密切关系,目前,国内外相继开展该项技术。近10年来国外已作DBS手术2万例次,国内自1998年以来已有10多家医院开展DBS手术,共作200多例。现将脑深部电刺激治疗PD现状及进展介绍如下。     

临时心脏起搏状态下的帕金森病DBS手术1例

目的总结临时心脏起搏状态下行帕金森病脑深部电刺激术(deep brain stimulation,DBS)的经验。方法回顾性分析1例原发性帕金森病病人的临床资料,因病情需要,在常规DBS术式基础上植入临时心脏起搏器,术后第2日,予拔除临时心脏起搏器。结果病人术后及开机后状态良好,未出现相关不适反应。结论心脏起搏器或者其他电子设备并不完全是DBS手术的禁忌证,但需要注意改变术前定位方法,并在术后选择合适的刺激模式和调控流程。     

60例帕金森病脑立体定向术的临床研究

目的：本研究旨在运用脑立体定向技术,治疗帕金森病,研究靶点的选择、影像学定位、电生理刺激,评估手术疗效。方法：通过CT或MR导向,辅以电生理刺激矫正靶点,对60例帕金森病（PD）患者行丘脑（Vim)或苍白球（PVP）进行射频术;或对底丘脑核（STN）进行脑深部刺激（DBS）。根据术前、术后Webster和UPDRS评分比较临床治疗效果。结果：在60例的手术治疗中,包括2例进行了二侧手术,5例进行了DBS,结果显示有效率100%,术后1月Wwebster评分下降了30%,UP-DRS评分下降了37%,患者生活质量明显提高,无永久性手术并发症和死亡。结论：从长期的治疗效果来看,PD的手术治疗优于单纯的药物治疗;通过MR导向,术中运用电生理刺激和微电极定位使靶点毁损更加准确;对于PD的主要症状的控制,选择Vim或PVP是最佳的靶点;DBS对PD症状的控制较毁损疗效持久,且并发症少,PD患者第二次手术靶点应首选PVP。     

功能磁共振对帕金森病脑深部电刺激术后运动症状改善的神经网络分析

目的 脑深部电刺激(deep brain stimulation, DBS)作为帕金森病的一种外科治疗方法，在临床上得到了广泛的应用，然而，其疗效的潜在机制仍然不详。本研究采用功能磁共振成像(functional magnetic resonance, fMRI)作为工具，试图探索与DBS有关的脑功能连接模式，并通过分析大脑功能连接来阐明DBS治疗的潜在机制。方法 41例诊断帕金森病并接受DBS治疗的患者，在手术前和手术后1年收集帕金森病评定量表(UPDRS III)数据。为了检查运动症状改善与大脑功能连接之间的关系，利用fMRI数据对皮层下连接网络进行相关性分析。应用线性回归来预测运动改善结果，并通过留一交叉验证法检验预测模型的准确性。结果 帕金森病患者fMRI所得脑功能连接与DBS手术临床结果存在相关性，功能连接分析显示双侧红核与壳核的功能连接与UPDRS-III评分的术后变化之间存在显着关联(左侧：r=-0.44,P=0.0056,右侧r=-0.46,P=0.0029)。结论 大脑红核和壳核之间的功能连接可以作为接受DBS手术的帕金森病患者治疗效果的重要预测指标。     

运动障碍病1135例手术治疗报告

目的 探讨手术治疗运动障碍病（MDs）的疗效、适应证、靶点选择和风险。方法 967名8个病种的MDs患者接受了1135例次的微电极导向立体定向神经外科手术。靶点选择苍白球腹后部（PVP）、丘脑腹外侧核和丘脑底核（STN）。通过毁损或脑深部电刺激（DBS）靶点达到症状学治疗的 目的。采用国际通用的疗效评估方法，对特定本组之间进行比较。结果 帕金森病（PD）是MDs手术治疗中主要的病种（88.3%），PVP是目前主要的治疗靶点（64.8%），手术明显改善了患者的生存质量。初步结果显示STN和DBS对PD的改善程度高于PVP。手术风险为1.8%。结论 手术对MDs有肯定和持久的疗效。STN可能是最具潜力的PD治疗性核团。     

丘脑底核脑深部电刺激对帕金森病术后药物治疗的影响(附40例分析)

目的 观察帕金森病（PD）病人丘脑底核脑深部电刺激（STN—DBS）术后药物变化情况。探讨STN—DBS对帕金森病术后药物治疗的影响。方法 对接受STN—DBS手术治疗的40例帕金森病病人手术前后的药物服用剂量、药物引起的相关并发症等情况进行回顾性分析。结果 本组经6～49个月随访。多数病人在STN-DBS作用下因症状明显改善，于开机后的1-6个月间使用抗PD药物逐渐减量。最终的选择剂量可维持2年以上。开机后5例不再服用相关药物。25例药物较术前平均减少60％。7例药物用量与术前相同，3例行单侧STN—DBS者术后药物用量增加。药物相关并发症因术后药物用量的减少而得到明显缓解。结论 STN—DBS能够减少术后抗PD药物的用量。改善药物引起的相关并发症。     

脑深部刺激术治疗帕金森病异动症的疗效与机制研究

左旋多巴诱导的异动症(L-dopa-induced dyskinesia,LID)是帕金森病最常见的致残性晚期药物并发症,脑深部刺激术(deep brain stimulation,DBS)已替代毁损术成为帕金森病外科治疗的新方法,具有创伤小、可逆性、可调控等优点,常用的治疗靶点包括丘脑底核(subthalamic nucleus,STN)和苍白球内侧部(pallidus internus,GPi),但是DBS的具体作用机制、对于LID临床疗效的改善程度以及针对不同病人的最佳手术靶点选择尚存在争议,本文将结合近期最新的文献对上述问题进行综述。     

脑深部电刺激治疗帕金森病的临床应用

目的 探讨脑深部电刺激术(DBS)治疗帕金森病(PD)的手术方法和脉冲发生器程控调节。方法 脑深部电刺激术治疗帕金森病36例，其中丘脑底核(STN)35例和丘脑腹中间核(Vim)1例，单侧18例，双侧18例。采用磁共振扫描结合微电极记录技术进行靶点定位。术后用UPDRS运动评分评价刺激效果。结果 36例PD患者术后随访2～32个月，平均6．3个月。脉冲发生器开启时，在“关”状态下，UPDRS运动评分改善率45．2％；在“开”状态下，UPDRS运动评分改善率20．7％，未发现任何并发症。结论 DBS能有效控制PD症状，手术并发症少，术后可调节参数，已成为治疗帕金森病的重要手术方法。     

Measurement of tissue electrical impedance confirms stereotactically localized internal segment of the globus pallidus during surgery

Lesions surgically made in the internal segment of the posteroventral globus pallidus (Gpi) reduce many medically intractable symptoms in patients with Parkinson's disease. The Gpi is localized for pallidotomy by stereotactic procedures. We sought to confirm the stereotactically localized Gpi segment by measuring impedance between the tip of an active electrode that was advanced toward the target and a remote reference electrode. A stereotactic instrument was used to place an active electrode in 53 conscious patients undergoing pallidotomy. The electrode was manually advanced slowly toward the Gpi segment by a microdrive. Impedance was measured every 10 mm initially and every 1 mm in the final 10 mm of the electrode's advancement, using an impedance monitor interconnected with a lesion generator. Measurements were continued for several millimeters after each patient's target was reached. Impedance values ranged from 250 to 350 ohms throughout of the electrode passage. Impedance increased by 25-35 ohms at 1-3 mm before the center of the target and then dropped abruptly when the electrode passed the target. Impedance values depended strongly on the electrode's configuration. The impedance measurement confirmed the location of each surgical target identified by stereotactic navigation. The accuracy of the impedance measurement is acceptable, and the procedure can be recommended as an aid to confirm the stereotactically localized Gpi during neurological surgery.     

The effects of varying schedules of time-out on aggressive behavior of a retarded girl

Three schedules of time-out were compared for suppressing aggressive behavior in a 7-yr-old retarded girl. The schedules (FR5, FR2, CRF) were time-out after every 5th, 2nd or every aggressive act. The FR5 schedule had no effect on rate of aggressive behavior while the FR2 and CRF schedules both produced significant reductions, the CRF being more effective. This reduction was maintained at follow-up after 5 weeks. It appears that time-out may be effective proportionate to the percentage of target behaviors it follows, and that some success can be achieved with less than continuous application.     

Semantic Search in the Remote Associates Test

Searching through semantic memory may involve the use of several retrieval cues. In a verbal fluency task, the set of available cues is limited and every candidate word is a target. Individuals exhibit clustering behavior as predicted by optimal foraging theory. In another semantic search task, the remote associates task (RAT), three cues are presented and a single target word has to be found. Whereas the task has been widely studied as a task of creativity or insight problem solving, in this article, the RAT is treated as a semantic retrieval task and assessed from the perspective of information foraging theory. Experiments are presented that address the superadditive combination of cues and the anti-clustering behavior in the recall sequence. A new type of search behavior in the RAT is put forward that involves maximizing the difference in activation between target and distractors. This type of search is advantageous when the target is weak and cue patches are contaminated with strong competitors.     

基于空间自动配准手术计划系统的设计和实现****

文章提出了一种基于手术空间和图像空间自动配准的手术计划系统设计和实现方法：①选取3个有一定间隔的横断面。②使用模板匹配法自动识别每一个横断面上的标志点。③用识别的数据建立手术空间和图像空间的刚体变换模型,再用最小二乘法解方程组得到两个空间的最优变换矩阵和平移矩阵。最后再通过建立脑空间和图像空间映射关系来计算功能靶点坐标。基于以上算法设计了手术计划系统软件,对比了手动和自动方法识别标志点的运行时间,并设计系统改进前后功能靶点计算值和手术空间实际测量值对比实验。结果证明以上方法有较好的靶点计算速度和精度。     

Behavioral factors in the placebo response

Given its presence in almost every clinical trial, the placebo is the most frequently studied substance in clinical research. Demonstration of treatment efficacy demands that the target (active) agent must be shown to be statistically significantly superior to an inert substance (placebo) not believed to be a specific therapy for the target condition. In clinical practice, enhancing the non-specific factors that contribute to an enhanced treatment outcome is desirable to maximize the likelihood of therapeutic benefit. Variables affecting the impact of placebo on clinical research and practice remain poorly understood, however, as they have not been systematically studied. The present article will discuss behavioral factors that have been found to be relevant in placebo mechanisms.     

Auditory and visual P300 topography from a 3 stimulus paradigm.

OBJECTIVE: The P300 event-related brain potential (ERP) was elicited with auditory and visual stimuli in a separate session of a 3 stimulus oddball paradigm, and the scalp topography was assessed with 15 electrode locations. METHODS: Target (0.10), standard (0.80), and infrequent non-target (0.10) stimuli in the auditory task were 2000, 1000 and 500 Hz tone, and in the visual task, 'X', 'O', and 'H', respectively. The stimuli were presented in a random series, once every 2 s, and participants responded only to the target (N = 12). RESULTS: Target stimuli elicited larger P300 components than non-target did in both stimulus modalities. For both target and non-target stimuli, P300 amplitude was larger and latency longer for the visual compared with the auditory stimulus. Analysis of normalized P300 amplitude data indicated that the target and non-target P300s from both modalities had identical topography. CONCLUSION: The findings suggest that both target and non-target stimuli in 3 stimulus oddball paradigm elicited the same type of P300 (P3b) for both stimulus modalities.     

Quick minds don't blink: electrophysiological correlates of individual differences in attentional selection

A well-established phenomenon in the study of attention is the attentional blink-a deficit in reporting the second of two targets when it occurs 200-500 msec after the first. Although the effect has been shown to be robust in a variety of task conditions, not every individual participant shows the effect. We measured electroencephalographic activity for "nonblinkers" and "blinkers" during execution of a task in which two letters had to be detected in an sequential stream of digit distractors. Nonblinkers showed an earlier P3 peak, suggesting that they are quicker to consolidate information than are blinkers. Differences in frontal selection positivity were also found, such that nonblinkers showed a larger difference between target and distractor activation than did blinkers. Nonblinkers seem to extract target information better than blinkers do, allowing them to reject distractors more easily and leaving sufficient resources available to report both targets.     

Slow saccades in spinocerebellar degeneration.

Two patients with spinocerebellar degeneration made abnormally slow horizontal refixations. One patient produced quick phases of nystagmus with identical maximum velocities, suggesting her refixations were abnormal saccades and not voluntary pursuit movements. In response to double target jumps, neither patient showed an obligatory refractory period after each saccade; they responded to every target movement after one reaction time. Their slow refixations were not preprogrammed since they could be modified in flight. To reconcile these observations with normal saccadic behavior, we hypothesized a neural network that made saccades by driving the eyes to an orbital position rather than preprogramming a distance for movement. Computer simulation of this model produced both realistically appearing normal saccades and, when appropriately "lesioned" to simulate a loss of saccadic "burst" neurons in the pontine reticular formation, slow saccades that could be modified in flight.     

Epilepsy and Education

Summary: Epilepsy education continues to be an essential component of every epilepsy organization'smission. Ongoing educational programs are an essential part of epilepsy patient care. A few basic rules to ensure success are to: (a) identify needs by users, not providers; (b) target programs to the specific audience; (c) remember that people learn by different methods; (d) take advantage of teachable moments; (e) account for transcultural differences; and (f) modify programs based on systemative evaluation and feedback.     

Size contrast and assimilation explained by the statistics of natural scene geometry

The term "size contrast and assimilation" refers to a large class of geometrical illusions in which the apparent sizes of identical visual targets in various contexts are different. Here we have examined whether these intriguing discrepancies between physical and perceived size can be explained by a visual process in which percepts are determined by the probability distribution of the possible real-world sources of retinal stimuli. To test this idea, we acquired a range image database of natural scenes that specified the location of every image point in 3-D space. By sampling the possible physical sources of various size contrast or assimilation stimuli in the database, we determined the probability distributions of the size of the target in the images generated by these sources. For each of the various stimuli tested, these probability distributions of target size in different contexts accurately predicted the perceptual effects reported in psychophysical studies. We conclude that size contrast and assimilation effects are a further manifestation of a fundamentally probabilistic process of visual perception.