Effect of interictal epileptiform discharges on EEG-based functional connectivity networks

ObjectiveFunctional connectivity networks (FCNs) based on interictal electroencephalography (EEG) can identify pathological brain networks associated with epilepsy. FCNs are altered by interictal epileptiform discharges (IEDs), but it is unknown whether this is due to the morphology of the IED or the underlying pathological activity. Therefore, we characterized the impact of IEDs on the FCN through simulations and EEG analysis.MethodsWe introduced simulated IEDs to sleep EEG recordings of eight healthy controls and analyzed the effect of IED amplitude and rate on the FCN. We then generated FCNs based on epochs with and without IEDs and compared them to the analogous FCNs from eight subjects with infantile spasms (IS), based on 1340 visually marked IEDs. Differences in network structure and strength were assessed.ResultsIEDs in IS subjects caused increased connectivity strength but no change in network structure. In controls, simulated IEDs with physiological amplitudes and rates did not alter network strength or structure.ConclusionsIncreases in connectivity strength in IS subjects are not artifacts caused by the interictal spike waveform and may be related to the underlying pathophysiology of IS.SignificanceDynamic changes in EEG-based FCNs during IEDs may be valuable for identification of pathological networks associated with epilepsy.     

听觉诱发电位指数、脑电双频指数对异丙酚麻醉下患者术中体动反应的预测

目的评价听觉诱发电位指数(AAI)、脑电双频指数(BIS)预测异丙酚麻醉下患者术中体动反应的可能性。方法择期行妇科手术全麻患者28例,ASAⅠ或Ⅱ级,年龄24-62岁,体重46- 71 kg,术前2 h口服咪达唑仑10 mg,入室后以血浆靶浓度3．5μg/ml靶控输注异丙酚、静脉注射芬太尼2μg／kg及维库溴铵0．1 mg／kg麻醉诱导,气管插管后,调整异丙酚血浆靶浓度维持BIS 40-60。切皮后不再追加肌松剂,观察患者术中头面部及四肢的体动反应,记录体动反应发生前、后2min内BIS、AAI的最大值(BISmax、AAImax)及此时段内BIS>75、AAI>40的次数及出现时间。记录术中当BIS>75、AAI>40时前、后2 min内有无体动反应发生及发生时间。结果12例出现体动反应,体动前、后2 min内BISmax为63±16(4例BIS>75,33．3％),AAImax为48±11(12例AAI>40,100％)。麻醉维持过程中,出现14次BIS>75,并发体动反应4次(28．5％),BIS反应时间较体动时间滞后(84±19)s;出现AAI>40者28次,并发体动者12次(42．8％),AAI反应时间较体动时间滞后(13±3)s。结论异丙酚麻醉下BIS、AAI反应时间较体动发生时间滞后,不能预测术中体动反应的发生。     

Recognition Impairment Correlated with Short Bisynchronous Epileptic Discharges

The occurrence of transitory cognitive impairment during diffuse subclinical electroencephalographic (EEG) discharges has been widely documented but the role of the parameters influencing the cognitive performance and the involvement of motor or verbal response in the tasks used is still under debate. Fifteen patients suffering from primary generalized epilepsy with frequent bisynchronous EEG epileptic bursts underwent a shape recognition task during EEG monitoring. The test sequence was as follows: memorandum, pause, and multiple choice set. After pressing the response button, the patient was asked to confirm the choice verbally. The following parameters were considered: geometrical complexity of the shape, chronological position of the burst occurring during the single test, and the duration of discharge ranging from 1 to 3 s. Results showed a significant increase in incorrect responses during the test when discharges occurred, with more errors occurring for difficult than for easy shapes. Neither the discharge position nor the duration of the epileptic burst influenced the performance. Diffuse epileptic activity of short duration produced selective effects on the cognitive process regardless of the motor component of the response.     

Juvenile Myoclonic Epilepsy: Factors of Error Involved in the Diagnosis and Treatment

Juvenile myoclonic epilepsy (JME), a common form of idiopathic generalized epilepsy, has a distinct clinical and electroencephalographic profile. Often JME is not recognized, with serious consequences on the sufferers. We examined factors contributing to the missed diagnosis even in an epilepsy clinic. Of 70 JME patients, 66 (91.4%) were not diagnosed on referral and 22 (33%) were not initially recognized in the epilepsy clinic. The correct diagnosis was established after a mean of 8.3 +/- 5.5 years from disease onset and an interval of 17.7 +/- 10.4 months from first evaluation in the epilepsy clinic. Myoclonic jerks, the hallmark of the disease, were not usually reported by patients. Similarly, relevant questioning may not be included in the history. Absence seizures antedating jerks by many years, myoclonic jerks reported as unilateral, generalized tonic-clonic seizures occurring during sleep and focal EEG abnormalities are other factors contributing to not recognizing JME. Our study reemphasizes the need to have not only a correct seizure diagnosis but also a correct epilepsy-disease diagnosis.     

Generalized Convulsive Status Epilepticus in the Adult

Summary: Status epilepticus (SE) is denned as recurrent epileptic seizures without full recovery of consciousness before the next seizure begins, or more-or-less continuous clinical and/or electrical seizure activity lasting for more than 30 min whether or not consciousness is impaired. Three presentations of SE are now recognized: recurrent generalized tonic and/or clonic seizures without full recovery of consciousness between attacks, nonconvulsive status where the patient appears to be in a prolonged "epileptic twilight state," and continuous/repetitive focal seizure activity without alteration of consciousness. Generalized convulsive status epilepticus (GCSE) encompasses a broad spectrum of clinical presentations from repeated overt generalized tonic-clonic seizures to subtle convulsive movements in a profoundly comatose patient. Thus, GCSE is a dynamic state that is characterized by paroxysmal or continuous tonic and/or clonic motor activity, which may be symmetrical or asymmetrical and overt or subtle but which is associated with a marked impairment of consciousness and with bilateral (although frequently asymmetrical) ictal discharges on the EEG. Just as there is a progression from overt to increasingly subtle clinical manifestations of GCSE, there is also a predictable sequence of progressive EEG changes during untreated GCSE. A sequence of five patterns of ictal discharges has been observed: discrete electrographic seizures, waxing and waning, continuous, continuous with flat periods, and periodic epileptiform discharges on a relatively flat background. A patient actively having seizures or comatose who exhibits any of these patterns on EEG should be considered to be in GCSE and should be treated aggressively to stop all clinical and electrical seizure activity to prevent further neurological morbidity and mortality.     

24h动态脑电图在儿童癫痫和非癫痫疾病的应用价值

目的探讨24h动态脑电图在儿童癫痫的诊断与鉴别诊断中的应用价值.方法 2002年2月至2004年10月在我院儿科病房和门诊就诊的具有发作性症状病例149例,其中拟诊癫痫52例,非癫痫性发作性疾病97例,全部病例作常规脑电图(EEG)和24h动态脑电图(AEEG)检查.结果拟诊癫痫52例,经24h动态脑电图监测,结合其临床表现,确诊为癫痫40例;而非癫痫性发作性疾病97例,经24h动态脑电图监测,并结合其临床表现,90例被除外癫痫.结论 24h动态脑电图对儿童发作性疾病,尤其是癫痫与非癫痫性发作性疾病的诊断与鉴别诊断具有重要价值,同时24h动态脑电图还可揭示癫痫灶的起源,有助于癫痫和癫痫综合征的分类,为正确治疗提供依据.     

舒芬太尼复合异丙酚麻醉下体外循环冠脉搭桥术患者双频谱指数与熵指数的关系

目的评价非肌松、深麻醉状态下,双频谱指数(BIS)反映麻醉深度的准确性。方法选择ASAⅢ级的冠脉搭桥术患者59例,麻醉诱导:静脉注射异丙酚2 mg／kg、舒芬太尼1μg／kg、罗库溴铵0．6 mg／kg,术中麻醉维持采用静脉持续输注异丙酚3-4 mg·kg-1·h-1、舒芬太尼1μg·kg-1·h-1。于麻醉诱导前、麻醉诱导开始后1、2、3、4 min、气管插管后即刻、气管插管后1 min、切皮后即刻和劈胸骨后即刻记录BIS、状态熵(SE)和反映熵(RE)。结果与麻醉诱导前相比,麻醉诱导开始后1、2、3、4 min和气管插管后即刻、气管插管后1 min、切皮后即刻及劈胸骨后即刻BIS、SE和RE均下降(P<0．05)。与SE相比,RE在各观察点均升高(P<0．01)。麻醉诱导期间BIS与SE和RE各时间点观察值之间呈明显正相关,r分别为0．898、0．908(P<0．01)。结论在非肌松、深麻醉状态下,BIS对舒芬太尼复合异丙酚静脉麻醉深度的监测不受肌电活动的影响。     

事件相关电位和脑电图在痴呆早期诊断中的意义

目的 研究血管性痴呆（vascular dementia，VD）患者ERP和EEG的变化特征，并与神经心理学及痴呆程度进行相关性分析。方法 测定68例VD患者及37例健康志愿者的事件相关电位（ERP：N100，P300）、脑电图（EEG），同时采用MMSE进行认知功能评定，并进行相关性分析。结果 68例VD组患者的P300潜伏期明显延长，波幅明显降低，与正常对照组比较有明显差异性（P〈0.01，P〈0.05），N100潜伏期。波幅变化不是很大（P〉0.05），脑电图异常率，VD组94%，正常对照组18%，2组比较有明显差异性（P〈0.01）。VD组患者ERP异常程度与EEG异常程度经相关性分析无相关性。VD组MMSE与正常对照组比较有明显差异（P〈0.05），VD组MMSE评分与P300PL呈负相关（r=-0.57，P〈0.05），与P300AMP呈正相关（r=0.37，P〉0.05）。结论 ERP与认知功能存在明显相关性，提示了ERP是反映其认知功能障碍程度的客观指标之一，可作为检测高危人群普查的手段之一，ERP在判断认知功能方面敏感于其他检查手段，客观性强。     

SNAP指数监测瑞芬太尼-异丙酚麻醉患者镇静深度的可行性

目的 探讨SNAP指数（SI）监测异丙酚一瑞芬太尼麻醉患者镇静深度的可行性。方法 40例择期全麻手术男性患者，ASA Ⅰ或Ⅱ级，年龄18～60岁，体重指数20～30kg／m^22，随机分为R0、R2、R4、R6组，每组10例。R0组麻醉诱导时靶控输注（TCI）0．9％生理盐水，R2、R4、R6组分别以效应室靶浓度2、4、6n/MLTCI瑞芬太尼，输注10min时开始TCI异丙酚，异丙酚初始效应室靶浓度均为1．5μg／ml，每4min增加0．5μg／ml，改良警觉／镇静（OAA／S）评分为1分时给予强直刺激，记录在临床目标（改良OAA／S评分为1分、睫毛反射消失、对强直刺激反应消失）出现时SI、脑电双频谱指数（BIS）、异丙酚效应室靶浓度（Ct）、异丙酚效应室浓度（Ce），并对SI与改良OAMS评分、BIS、Ct、Ce进行直线相关分析。结果 SI与改良OAA／S评分、BIS呈正相关，SI与Ct（除外R4组）及Ce（除外R2组）呈负相关；四组睫毛反射消失时SI差异无统计学意义（P〉0．05）；与R0组比较，对强直刺激反应消失时其它三组SI升高，Ct及Ce降低（P〈0．05）。结论 SI可用于瑞芬太尼-异丙酚麻醉患者镇静深度的监测。     

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.