脑电反馈治疗注意缺陷多动障碍儿童的有效性分析

目的 探讨脑电反馈治疗不同类型注意缺陷多动障碍(ADHD)的有效性。方法 将符合美国精神障碍诊断与统计手册第4版标准的30例ADHD儿童，分为三个不同亚型接受脑电反馈治疗，分别于训练20次及40次后对疗效进行评定。结果 经过20次及40次训练，各亚型患儿与训练前相比，脑电反馈商数及临床症状均有显著改善；40次与20次相比，脑电反馈商数多动-冲动型无显著变化，其他二型仍有显著好转。结论 脑电反馈治疗对ADHD各亚型的疗效肯定；对注意缺陷为主型和混合型患儿训练时间应比多动-冲动为主患儿训练时间长。     

不同靶浓度异丙酚对腹部手术病人异氟醚呼气末浓度的影响

目的以脑电双频指数(BIS)值45～55作为麻醉深度监测指标,观察不同靶浓度异丙酚对腹部手术病人异氟醚呼气末有效浓度的影响,并初步探讨额肌电(EMG)作为麻醉深度监测指标的意义.方法选择60例ASAⅠ～Ⅱ级择期行腹部手术的病人,随机分为三组Ⅰ组(n=20)麻醉诱导后单纯吸入异氟醚;Ⅱ组(n=20)吸入异氟醚的同时输注靶浓度为1μg/ml的异丙酚;Ⅲ组(n=20)吸入异氟醚的同时输注靶浓度为2μg/ml的异丙酚.全麻诱导采用咪达唑仑、芬太尼、维库溴铵,气管插管后启动靶控输注异丙酚.根据BIS值的变化调节异氟醚吸入浓度,维持BIS值在45～55范围.麻醉中连续观察平均动脉压(MAP)、心率(HR)、脉搏氧饱和度(SpO2)、BIS及EMG的变化,并持续监测异氟醚的吸入和呼气末浓度.结果三组病人年龄、性别、体重、麻醉时间、术中芬太尼用量、MAP、HR及SpO2的变化组间比较差异无显著性(P＞0.05);Ⅱ组、Ⅲ组插管后和切皮后异氟醚呼气末浓度均低于Ⅰ组(P＜0.01),Ⅱ组、Ⅲ组呼气末异氟醚有效浓度分别为0.43%±0.08%、0.21%±0.06%,较Ⅰ组分别降低43.4%、72.3%(P＜0.05).入室后麻醉用药前EMG为46～53(BIS值91～96).麻醉诱导后及术中EMG维持在26～29(BIS值45～55),麻醉恢复期EMG逐渐升高,当大于40时(相应BIS值80～85),大部分病人能够呼之睁眼.结论随异丙酚靶浓度的增加,维持BIS值为45～55时的异氟醚的呼气末浓度随之降低.EMG作为麻醉深度的监测指标有一定意义.     

真菌性脑膜炎继发癫临床研究

对10例真菌性脑膜炎继发癫患者的临床表现,以及脑脊液、影像学和脑电图特点进行回顾分析,提示真菌性脑膜炎累及大脑皮质者易继发癫,尤其是影像学检查发现额颞叶病灶、脑电图呈中至重度异常的患者更易诱发癫发作。真菌性脑膜炎患者脑脊液内毒素和(1-3)-β-D葡聚糖水平均升高,是否与继发癫相关尚待进一步观察。     

脑死亡评估的研究

目的 探讨准确、客观评估脑死亡的方法。方法 2002年4月至2003年4月神经重症监护治疗病房采用临床指标及脑电图、脑干诱发电位(BAEP)、短潜伏期体感诱发电位(SLSEP)和经颅多普勒超声(TCD)等实验室指标对11例脑死亡进行动态评估研究。结果 全部病例深昏迷,格拉斯哥昏迷评分3分,脑干反射和脑神经支配的活动消失。全部病例脑电波静息,其中3例存在静息过程。全部病例BAEP主波消失,1例存在主波消失过程。全部病例SLSEP的N13以后波形消失。TCD检测除1例为极重度颅内压增高血流改变外,其他全部为脑死亡血流特征。自主呼吸诱发试验和阿托品试验为脑死亡提供了最后的证据。脑死亡的主要原因是呼吸心跳骤停、急性低氧血症和(或)低血压。结论 实验室多项评估指标结合,尤其是临床指标与实验室指标的结合,以及动态观察可提高判断的准确性。     

缺血性卒中后异常脑电发放临床及脑电图特征

目的探讨缺血性卒中后异常脑电发放的临床及脑电图特征。方法回顾分析162例缺血性卒中患者临床和24 h动态脑电图特征。结果 162例缺血性卒中患者中87例(53.70%)24 h动态脑电图异常,其中24例(27.59%)梗死灶部位与脑电图异常放电部位相一致(一致组)、63例(72.41%)不一致(不一致组)。两组患者缺血性卒中临床分型[英国牛津郡社区脑卒中项目(OCSP)分型]和病因分型(TOAST分型)差异均无统计学意义(P=0.792,0.111),梗死灶部位差异有统计学意义(P=0.000)。一致组患者24 h动态脑电图可见背景节律慢化,以及尖波和尖-慢复合波,且与梗死灶部位相一致;不一致组患者各导联背景节律均发生变化,梗死灶位于单侧大脑半球者可见对侧大脑半球异常放电,梗死灶范围局限但脑电图可见异常放电范围广泛,梗死灶仅位于皮质下脑深部结构但可于头皮电极记录到异常放电。两组患者癫发生率差异无统计学意义(P=0.908),而癫发作类型差异有统计学意义(P=0.000)。结论梗死灶部位影响异常脑电活动的发放和扩布,其与记录到异常放电的导联部位不一致对缺血性卒中后癫发作类型和预后有提示作用。     

Neural correlates of apathy in patients with neurodegenerative disorders,acquired brain injury,and psychiatric disorders

Apathy can be described as a loss of goal-directed purposeful behavior and is common in a variety of neurological and psychiatric disorders. Although previous studies investigated associations between abnormal brain functioning and apathy, it is unclear whether the neural basis of apathy is similar across different pathological conditions. The purpose of this systematic review was to provide an extensive overview of the neuroimaging literature on apathy including studies of various patient populations, and evaluate whether the current state of affairs suggest disorder specific or shared neural correlates of apathy. Results suggest that abnormalities within fronto-striatal circuits are most consistently associated with apathy across the different pathological conditions. Of note, abnormalities within the inferior parietal cortex were also linked to apathy, a region previously not included in neuroanatomical models of apathy. The variance in brain regions implicated in apathy may suggest that different routes towards apathy are possible. Future research should investigate possible alterations in different processes underlying goal-directed behavior, ranging from intention and goal-selection to action planning and execution.     

Status epilepticus in central nervous system infections: an experience from a developing country

Objective

There is a paucity of comprehensive study in status epilepticus in central nervous system infections. This observational study evaluated the response to antiepileptic drugs in patients with status epilepticus and central nervous system infection.

Methods

The study took place at a tertiary care teaching hospital in India. A total of 37 of 93 adult patients (39.8%) with status epilepticus had central nervous system infection, and they underwent clinical evaluation, including status type and duration. Magnetic resonance imaging and cerebrospinal fluid analyses were performed. Patients were categorized into encephalitis, meningitis, and granuloma groups. The response to antiepileptic drugs was noted, and the status was considered refractory if seizures continued after the second antiepileptic drug. Refractory status epilepticus and mortality were correlated with the type of infection and various clinical and magnetic resonance imaging findings.

Results

The median age of the patients was 37 years (16-78 years), and 17 patients were female; 35 patients had convulsive status epilepticus, and 2 patients had nonconvulsive status epilepticus. Twenty patients had encephalitis (Japanese 4, herpes simplex 3, nonspecific 12), including 1 patient with malaria, 9 patients with meningitis (tubercular 5, pyogenic 3, fungal 1), and 7 patients with granuloma (tubercular 5, neurocysticercosis 2). The mean duration of status epilepticus was 19.6 hours (0.25-72 hours). Magnetic resonance imaging results were abnormal in 66.7% of patients. In 67.6% of patients, status epilepticus was controlled after the first antiepileptic drug. Some 24.3% of patients were refractory to the second antiepileptic drug, and 10.8% of patients did not respond to the third antiepileptic drug. Patients with encephalitis had an insignificantly poor response. Eleven patients (29.7%) died, and mortality was higher in patients with refractory status epilepticus.

Conclusion

Of patients with status epilepticus and central nervous system infection, 24.3% had a refractory status that was associated with a high mortality. Their response to an antiepileptic drug in encephalitis was insignificantly poorer.     

On utilizing uncertainty information in template‐based EEG‐fMRI ballistocardiogram artifact removal

The correction of ballistocardiogram artifacts in simultaneous EEG‐fMRI often yields unsatisfactory results. To improve the signal‐to‐noise ratio (SNR) of results, we inferred EEG signal uncertainty from postcorrection artifact residuals and computed the uncertainty‐weighted mean of ERPs. Using an uncertainty‐weighted mean significantly and consistently reduced both inter‐ and intrasubject SEM in the analysis of auditory evoked responses (AER, indicated by the N1‐P2 complex) and in the effects of an auditory oddball paradigm (N1‐P3 complex, standard‐deviant difference). SNR increased by 3% on average for the AER amplitude (intrasubject) and 17% on average for the auditory oddball ERP (intersubject). This demonstrates that weighting by uncertainty complements existing artifact correction algorithms to increase SNR in ERPs. More specifically, it is an efficient method to utilize seemingly corrupt (difficult‐to‐correct) EEG data that might otherwise be discarded.     

External induction and stabilization of brain oscillations in the human

BackgroundNeural oscillations in the cerebral cortex are associated with a range of cognitive processes and neuropsychiatric disorders. However, non-invasively modulating oscillatory activity remains technically challenging, due to limited strength, duration, or non-synchronization of stimulation waveforms with endogenous rhythms.ObjectiveWe hypothesized that applying controllable phase-synchronized repetitive transcranial magnetic stimulation pulses (rTMS) with alternating currents (tACS) may induce and stabilize neuro-oscillatory resting-state activity at targeted frequencies.MethodsUsing a novel circuit to precisely synchronize rTMS pulses with phase of tACS, we empirically tested whether combined, 10-Hz prefrontal bilateral stimulation could induce and stabilize 10-Hz oscillations in the bilateral prefrontal cortex (PFC). 25 healthy participants took part in a repeated-measures design. Whole-brain resting-state EEG in eyes-open (EO) and eyes-closed (EC) was recorded before (baseline), immediately (1-min), and 15- and 30-min after stimulation. Bilateral, phase-synchronized rTMS aligned to the positive tACS peak was compared with rTMS at tACS trough, with bilateral tACS or rTMS on its own, and to sham.Results10-Hz resting-state PFC power increased significantly with peak-synchronized rTMS + tACS (EO: 44.64%, EC: 46.30%, p < 0.05) compared to each stimulation protocol on its own, and sham, with effects spanning between prefrontal and parietal regions and sustaining throughout 30-min. No effects were observed with the sham protocol. Moreover, rTMS timed to the negative tACS trough did not induce local or global changes in oscillations.ConclusionPhase-synchronizing rTMS with tACS may be a viable approach for inducing and stabilizing neuro-oscillatory activity, particularly in scenarios where endogenous oscillatory tone is attenuated, such as disorders of consciousness or major depression.