Surgical Treatment of Intractable Seizures Due to Hypothalamic Hamartoma

Summary: A 6.5-year-old boy developed seizures at age 2.8 years consisting of episodes of unconsciousness and laughing attacks. By age 6 years, multiple seizure types, including generalized tonic-clonic (GTC), complex partial (CPS) and akinetic seizures, and drop attacks were occurring several times daily. EEG showed multifocal epileptic discharges. Antiepileptic drugs (AEDs) did not control the seizures. With progression of the epilepsy, cognitive deterioration developed. There were no manifestations of precocious puberty. Neuroimaging disclosed a suprasellar mass in continuity with the hypothalamus, and a diagnosis of hypothalamic hamartoma was made. After surgical resection of the hamartoma, the seizures were completely alleviated, and the epileptic EEG discharges disappeared. Improvement of mental function was also noted.     

靶控输注异丙酚意识消失时血浆和效应室浓度的EC50与脑电双频谱指数的关系多中心大样本临床研究

目的 研究择期手术患者靶控输注（TCI）异丙酚意识消失时血浆、效应室靶浓度的50%患者意识消失时的药物浓度（EC50）与脑电双频谱指数（BIS）的关系。方法 5家医疗中心405例择期手术患者（国人）,ASAⅠ或Ⅱ级。靶控输注异丙酚,以血浆靶浓度1．2μg/ml为起点,到达预期血浆靶浓度后每30秒递增0．3μg/ml,直至患者意识消失。采用概率单位回归分析计算患者意识消失时异丙酚血浆靶浓度、效应室靶浓度的EC05、EC50和EC95及其所对应的BIS。结果 择期手术患者TCI异丙酚意识消失时异丙酚血浆靶浓度EC05、EC50和EC95分别是2．9μg/ml、3．8μg/ml和4．8μg/ml,效应室靶浓度EC05、EC50和EC95分别是1．3μg/ml、2．2μg/ml和3．2μg/ml,50%患者意识消失的BIS是58,5%和95%患者意识消失的BIS分别是77和40。结论 择期手术患者TCI异丙酚意识消失时血浆靶浓度和效应室靶浓度EC50及95%置信区间分别是3．8μg/ml（3．8～3．9μg/ml）和2．2μg/ml（2．2～2．3μg/ml）, 50%患者意识消失的BIS用95%置信区间是58（58～59）。     

Ictal Clinical Electroencephalographic Findings of Spasms in West Syndrome

Summary: The electroencephalographic/video recordings of 955 spasms in children with cryptogenic and symptomatic West syndrome (WS) were reviewed to define the relation between a clinical manifestation of a spasm and its EEG pattern, and to examine whether these features reflect the etiology and prognosis of WS. The review confirmed the spasm to be a distinct type of seizure, with a unique clinical and EEG pattern unlike that of all other recognized seizures. Symmetric spasms were present in cryptogenic and symptomatic patients. In contrast, asymmetric spasms, or focal signs recognizable during a spasm, strongly indicated the existence of a cerebral lesion. In both etiological groups, the characteristic ictal EEG pattern of the spasms consisted of a positive-vertex slow wave. The other two patterns apparently correlated to a spasm, were fast activity, here called spindle-like, and decremental activity. The fast activity corresponded to a clinical stare, and the decremental activity, when present, represented a postictal event. Although it was independent from the etiology of the spasms, persisting hypsarrhythmia during a cluster of spasms appeared to be an EEG pattern that correlated with a favorable outcome.     

高血压急诊患者降压前后脑电图变化及临床意义

目的:观察高血压急诊快速降血压对大脑功能的影响情况。方法:监测56例病人含服 降压药前后的脑电活动和血压情况,并对所获资料进行分析。结果:2 h内收缩压(SBP)下降>5.33 kPa (40 mmHg)或舒张压(DBP)下降>4.00 kPa(30 mmHg)时,脑电图异常程度增加,θ及δ频段功率值明 显升高(P<0.01)。结论:降压急骤,可能会造成大脑功能损害     

The Topography of Non-Linear Cortical Dynamics at Rest, in Mental Calculation and Moving Shape Perception

Differential cortical activation by cognitive processing was studied using dimensional complexity, a measure derived from nonlinear dynamics that indicates the degrees of freedom (complexity) of a dynamic system. We examined the EEG of 32 healthy subjects at rest, during a visually presented calculation task, and during a moving shape perception task. As a nonlinear measure of connectivity, the mutual dimension of selected electrode pairs was used. The first Lyapunov coefficient was also calculated. Data were tested for non-linearity using a surrogate data method and compared to spectral EEG measures (power, coherence). Surrogate data testing confirmed the presence of nonlinear structure in the data. Cognitive activation led to a highly significant rise in dimensional complexity. While both tasks activated central, parietal and temporal areas, mental arithmetic showed frontal activation and an activity maximum at T3, while the moving shape task led to occipital activation and a right parietal activity maximum. Analysis of mutual dimension showed activation of a bilateral temporal-right frontal network in calculation. The Lyapunov coefficent showed clear topographic variation, but was not significantly changed by mental tasks (p<.09). While dimensional complexity was almost unrelated to power values, nonlinear (mutual dimension) and linear (coherence) measures of connectivity shared up to 37% of variance. Data are interpreted in terms of increased cortical complexity as a result of recruitment of asynchronously active, distributed neuronal assemblies in cognition. The topography of nonlinear dynamics are related to neuropsychological and neuroimaging findings on mental calculation and moving shape perception.     

Psychometric Properties of Resting Anterior EEG Asymmetry: Temporal Stability and Internal Consistency

We examined whether resting anterior electroencephalographic (EEG) asymmetry in the alpha frequency band has psychometric properties that would be expected of a measure assessing individual differences. In each of two experimental sessions, separated by three weeks, resting EEG in midfrontal and anterior temporal sites was recorded from 85 female adults during eight 60-s baselines. Resting alpha asymmetry demonstrated acceptable test-retest stability and excellent internal consistency reliability. Analyses including other frequency bands indicated that degree of stability varied somewhat as a function of band and region. In addition, asymmetry was less stable than absolute power. Discussion focuses on the implications of the present findings for the measurement and conceptualization of resting anterior asymmetry.     

Task-dependent changes in frontal brain asymmetry: effects of incentive cues, outcome expectancies, and motor responses

The current study was designed to clarify the psychological functions most closely associated with frontal brain asymmetry. Electroencephalography (EEG) was recorded from 60 participants while they performed a delayed reaction time (RT) task that included manipulations of incentive, expectancy, and response. Significant alpha asymmetry effects were reflected in topographic differences across anterior EEG sites. Variations in monetary incentives resulted in parametric changes in anterior frontal alpha asymmetry. Manipulations of outcome expectancies were related to mid-frontal EEG changes that differed for men and women. Varied response requirements were related to central asymmetry patterns. Taken together, the findings suggest that regionally specific patterns of frontal asymmetry are functionally related to particular aspects of approach-withdrawal tendencies involved in the temporal guidance and regulation of goal-directed behavior.     

Responses to Median and Tibial Nerve Stimulation in Patients with Chronic Neuropathic Pain

Somatosensory evoked magnetic fields and electrical potentials were measured in eight patients with unilateral neuropathic pain. After median nerve stimulation on the painful side, the amplitudes of the evoked responses were enhanced 2 to 3 times at a latency of about 100 ms compared to the responses of the contralateral, unaffected side. After posterior tibial nerve stimulation an enhancement was found at latencies around 110 ms and 150 ms. The scalp distribution of the magnetic field at the latencies of abnormal responses was dipolar and the responses could be ascribed to a current dipole. Three (of the eight) patients underwent spinal cord stimulation (SCS) for their pain. The enhancement of the evoked responses to stimulation of the painful side decreased after spinal cord stimulation. After a long period of spinal cord stimulation only (e.g., a year) during which the patient reported to be pain free, these abnormal responses were no longer observed.     

Lateralizing value of interictal spikes on overnight sleep-EEG studies in temporal lobe epilepsy

PURPOSE: To determine the lateralizing value of interictal epileptiform discharges (IEDs) recorded during overnight sleep-EEG studies in temporal lobe epilepsy. Because IEDs are more prevalent in non-rapid eye movement (NREM) sleep than in wakefulness, overnight sleep-EEG recordings may contribute additional lateralizing information to the epilepsy surgery evaluation beyond daytime EEGs. METHODS: Twenty-four subjects with medically refractory temporal lobe epilepsy underwent continuous overnight sleep-EEG recordings. Subjects were seizure free > or =24 h before study and receiving stable doses of medication. The IED foci recorded on overnight studies were compared with daytime EEGs, interictal samples, and ictal recordings during long-term monitoring, brain magnetic resonance images (MRIs), and surgical outcome. RESULTS: (a) In all 24 subjects, including 13 without IEDs on daytime EEGs, temporal IEDs were present during NREM sleep and were exclusively or predominantly (>95%) unilateral in 15 and bitemporal in nine. (b) Unilateral NREM IEDs were concordant with surface or depth ictal-onset regions in 14 subjects, even if MRIs were normal (three subjects) or surface ictal-onset regions were bilateral (five subjects). Eleven of 12 subjects with unilateral concordant NREM IEDs who have undergone surgery are seizure free. (c) Bitemporal IEDs were associated with postoperative seizures in all subjects with normal MRIs or widespread MRI abnormalities. However, all subjects with bitemporal IEDs and MRI hippocampal abnormalities concordant with ictal-onset regions had good to excellent surgical outcomes. CONCLUSIONS: When combined with other investigations, IEDs recorded on overnight studies add prognostic data to the epilepsy surgery evaluation not provided by daytime EEGs.