High-resolution EEG (HR-EEG) and magnetoencephalography (MEG)

HR-EEG (high resolution EEG) and MEG (magnetoencephalography) allow the recording of cerebral electromagnetic activities with excellent temporal resolution. These tools have also considerably progressed in spatial resolution and now constitute real methods of Electric and Magnetic Source Imaging. Their limits and the precision of the results obtained are discussed in distinct types of partial epilepsy. HR-EEG and MEG allow localization of scalp-EEG interictal spikes and more rarely ictal activities. They now contribute to the presurgical evaluation of pharmacoresistant partial epilepsies. These investigations appear to be of particular importance in presurgical assessment of MRI-negative epilepsy.     

Attentional modulation of SSVEP power depends on the network tagged by the flicker frequency

Modulation of the steady-state visual evoked potential (SSVEP) by attention was studied in detail using 15 'tag' frequencies in the range of 2.5-20 Hz. The stimuli were two series of random disc search arrays superimposed on two concentric color-marked annuli respectively. Two series of arrays were updated independently; one updated at one fixed frequency (flicker) and the other updated randomly according to a white noise distribution (random broadband flicker, rbbf). On each trial, the observer was instructed to attend one annulus and to detect a target (a triangle) that occasionally appeared in a random disc array in the attended annulus. The SSVEP results show that the choice of flicker frequency selects which cortical network synchronizes to the flicker two distinct cortical networks showed different effects of attention. SSVEP power and the effects of attention on SSVEP power strongly depend on both flicker frequency and radial position of rbbf annulus. At flicker frequencies in the delta band (2-4 Hz), and in the upper alpha band (10-11 Hz), an occipital-frontal network appears to phase-lock to the flicker when attending to the flicker, increasing the magnitude of the SSVEP. At flicker frequencies in the lower alpha band (8-10 Hz), a global response to a peripheral flickering stimulus, that includes parietal cortex and posterior frontal cortex, has higher amplitude when attention is directed away from the flickering peripheral stimulus and towards a competing rbbf stimulus in the fovea. Increases in SSVEP power when attention is directed to peripheral flicker are always associated with increases in phase locking. By contrast, at frequencies in the lower alpha band, increases in SSVEP power when attention is directed away from the flicker and towards foveal stimuli are not associated with changes in phase-locking. Thus, whether attention to a flicker stimulus increases or decreases SSVEP amplitude and phase locking depends on which of two cortical networks, which have distinct spatial and dynamic properties, is selected by the flicker frequency.     

补脾益肾颗粒联合脑电生物反馈治疗注意力障碍型儿童注意缺陷多动症

目的 观察补脾益肾颗粒联合脑电生物反馈治疗注意力障碍型儿童注意缺陷多动症临床疗效.方法 将注意力障碍型注意缺陷多动症患儿50例,采用随机数字表法随机分为对照组和治疗组,各25例,对照组采用脑电生物反馈仪治疗,治疗组在对照组治疗基础上给予补脾益肾颗粒口服.疗程均为4周,应用疾病疗效标准、治疗前后脑电θ/β值、注意缺陷与多动障碍量表及行为量表评分、精神科疾病临床疗效总评量表SI评分指标评定疗效.结果 治疗组总有效率为80.0％,显著高于对照组的60.0％ (P ＜0.05);治疗后2组脑电θ/β值、注意缺陷与多动障碍量表及行为量表评分、精神科疾病临床疗效总评量表SI评分均较治疗前显著降低,但治疗组低于对照组(P＜0.05).结论 补脾益肾颗粒联合脑电生物反馈治疗能明显改善注意力障碍型儿童注意缺陷多动症,疗效显著.     

超声结合视频脑电图在早产儿脑损伤早期诊断及预后评价中的应用

【摘要】 目的 探讨超声结合视频脑电图（VEEG）在早产儿脑损伤早期诊断及预后评价中的应用价值。 方法 选取出生后由产科转入新生儿重症监护室（NICU）的53例早产儿为研究对象,收集其临床资料,根据早产儿临床表现,将出生时Apgar评分低于7分、10d后经MRI检查确认有脑损伤改变的早产儿作为脑损伤组（n=24）,其他设为无脑损伤组（n=29）,所有早产儿出生后48h~72h均进行颅脑超声检查,且在床旁进行VEEG监测。 结果 超声诊断无脑损伤30例,脑损伤23例。VEEG监测显示脑损伤组及无脑损伤组分别有19例、5例早产儿出现脑电异常情况,脑损伤组VEEG脑电图异常率显著高于无脑损伤组（P＜0.05）。超声对早产儿脑损伤早期诊断的灵敏度、特异度、准确度分别为8.33%、89.66%、86.79%;VEEG对早产儿脑损伤早期诊断的灵敏度、特异度、准确度依次为79.17%、82.76%、81.13%;超声结合VEEG对早产儿脑损伤早期诊断的灵敏度、特异度、准确度分别为95.83%、96.55%、96.23%,均高于单纯超声和单纯VEEG检测（P＜0.05）。随访结果显示,12月龄时,超声结合VEEG诊断为脑损伤的早产儿MDI、PDI评分均较超声结合VEEG诊断为无脑损伤的早产儿低（P＜0.05）,脑瘫、癫痫发生率均较其高（P＜0.05）。 结论 超声结合VEEG能提高早产儿脑损伤早期诊断效能,在其预后评价中具有重要价值,可供临床借鉴。     

基于专利信息的EEG技术成熟度及技术网络分析

选取德温特专利索引数据库收录的EEG技术主题专利数据为研究样本,对EEG技术成熟度及技术网络进行分析。基于技术成熟度理论,绘制出技术S曲线模型,对EEG技术的生命周期、发展进程和未来趋势进行了研判。通过专利德温特分类代码的共类网络,进行聚类分析和战略坐标分析,从而揭示不同技术领域的关联关系和演变趋势。利用专利德温特手工代码的共词网络进行频次和中心性分析,以识别EEG技术的研究布局和热点研究主题。     

273例颞叶癫痫临床分析

目的 对273例颞叶癫痫患者的脑电图特征、影像学特点及服用抗癫痫药物的疗效进行分析总结,为临床颞叶癫痫的诊疗提供参考。方法 收集2013年1月~2014年12月诊断为颞叶癫痫患者的临床资料进行临床相关因素分析并对抗癫痫药物疗效进行评价。结果 273例颞叶癫痫患者中90.5%的患者长程视频脑电图出现异常,睡眠期痫样放电明显高于清醒期,影像学提示异常者166例,占全部患者的的60.8%。海马硬化或变性、颞叶蛛网膜囊肿、颞叶软化灶位居前3位,19~39岁为发病高峰年龄段,单药有效率在50%以上者占92.7%,联合用药有效率50%以上者占87.8%,两种药物治疗方式有效率经χ²检验比较,差异无统计学意义(P>0.05)。结论 颞叶癫痫以复杂部分性发作多见,海马硬化、颞叶软化灶、蛛网膜囊肿等为常见病因,90.5%的患者长程视频脑电图提示异常为临床诊断提供了重要的价值。两种药物治疗方式疗效差异无统计学意义,药物治疗仍是颞叶癫痫的主要治疗方法,奥卡西平、卡马西平、左乙拉西坦、丙戊酸等新型抗癫痫药物对颞叶癫痫疗效显著。     

Attentional capture during visual search is attenuated by target predictability: Evidence from the N2pc,Pd, and topographic segmentation

Attentional capture by salient distractors has been confirmed by the occurrence of an N2pc to the salient distractor. To clarify some failures to replicate this finding, we varied target predictability to induce different search modes. In the unpredictable target condition, the target shape varied randomly from trial to trial, favoring singleton detection mode. In the predictable target condition, the target shape remained the same in a block of trials, favoring feature search mode. With unpredictable targets, we observed an N2pc toward the salient color distractor, confirming attentional capture in singleton search mode. With predictable targets, there was no N2pc to the salient distractor, but a distractor positivity (Pd), suggesting distractor suppression. Also, differences emerged in the topographic segmentation of N2pc and Pd. Further, the amplitude of the N2pc toward the target was larger with predictable than with unpredictable targets.     

Mental rotation strategies reflected in event‐related (de)synchronization of alpha and mu power

During a mental rotation task of hands, participants mentally rotate their hand into the orientation of the shown hand. These mental movements are subject to the body's biomechanical constraints. In this study, we investigated whether the involvement of motor processes during the mental rotation process, as reflected in mu‐power desynchronization, is also influenced by one's movement capabilities. We performed an EEG study and used a delayed response mental rotation task of hands to examine the event‐related desynchronization differences between movements that are biomechanically easy and difficult to perform. Our results show an increase in event‐related desynchronization of the mu power for biomechanically easy compared to difficult‐to‐adopt postures. These findings provide further evidence for the notion that motor simulations can only be performed for movements that can already be performed overtly.     

Cortical potentials in an auditory oddball task reflect individual differences in working memory capacity

This study determined whether auditory cortical responses associated with mechanisms of attention vary with individual differences in working memory capacity (WMC) and perceptual load. The operation span test defined subjects with low versus high WMC, who then discriminated target/nontarget tones while EEG was recorded. Infrequent white noise distracters were presented at midline or ±90° locations, and perceptual load was manipulated by varying nontarget frequency. Amplitude of the N100 to distracters was negatively correlated with WMC. Relative to targets, only high WMC subjects showed attenuated N100 amplitudes to nontargets. In the higher WMC group, increased perceptual load was associated with decreased P3a amplitudes to distracters and longer‐lasting negative slow wave to nontargets. Results show that auditory cortical processing is associated with multiple facets of attention related to WMC and possibly higher‐level cognition.