Routine and sleep EEG: Minimum recording standards of the International Federation of Clinical Neurophysiology and the International League Against Epilepsy

This article provides recommendations on the minimum standards for recording routine (“standard”) and sleep electroencephalography (EEG). The joint working group of the International Federation of Clinical Neurophysiology (IFCN) and the International League Against Epilepsy (ILAE) developed the standards according to the methodology suggested for epilepsy-related clinical practice guidelines by the Epilepsy Guidelines Working Group. We reviewed the published evidence using the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. The quality of evidence for sleep induction methods was assessed by the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) method. A tool for Quality Assessment of Diagnostic Studies (QUADAS-2) was used to assess the risk of bias in technical and methodological studies. Where high-quality published evidence was lacking, we used modified Delphi technique to reach expert consensus. The GRADE system was used to formulate the recommendations. The quality of evidence was low or moderate. We formulated 16 consensus-based recommendations for minimum standards for recording routine and sleep EEG. The recommendations comprise the following aspects: indications, technical standards, recording duration, sleep induction, and provocative methods.     

300例癫痫及可疑癫痫患者AEEG分析

目的：对３００例癫痫及可疑癫痫患者的动态脑电图的应用价值进行了初步探讨。方法;使用北京明思公司ＳＷ－ＪＨ系列智能化脑电监护仪描记,并与常规脑电图比较。结果：３００例中ＥＥＧ异常５４例,ＡＥＥＧ异常１７８例ＡＥＥＧ痫样放电检出率明显高天ＥＥＧ。１４４例继发性癫痫患者中,ＥＥＧ异常８例,ＡＥＥＧ异常１０例,二者无显著性差异。     

动态脑电图在癫痫诊断及鉴别诊断中的价值

目的研究24 h动态脑电图(AEEG)在癫(疒间)的诊断及鉴别诊断中的价值.方法对761例临床拟诊为癫(疒间)及1327例可疑癫(疒间)患者的AEEG资料进行回顾性分析.结果两组AEEG与常规脑电图检查(疒间)样放电检出率比较差异有极显著性(均P＜0.005).230例患者通过AEEG监测证实为癫(疒间)发作.93例患者AEEG监测后发作类型得到了修正.结论 AEEG有助于癫(疒间)的诊断及鉴别诊断.     

Atlas of Electroencephalography, 3rd Edition

Electroencephalography (EEG) is the recording of the electrical activity of the brain. EEG is a reliable test to assess cerebral function. It aids in diagnosis, classification, and management of patients with epilepsy. It also has practical uses in conditions other than epilepsy. Moreover, it is harmless and inexpensive. EEG is an important tool for evaluating patients with epilepsy. It may help classify the syndrome, identify the likely source of focal seizures, and confirm a diagnosis of status epilepticus. EEG is therefore helpful when selecting appropriate antiepileptic drugs for patients with epilepsy, is valuable for diagnosis and management of status epilepticus as well as predicting the prognosis in epilepsy syndromes, and, is finally useful when localizing an area for resection in surgery candidates. In addition, despite advances in neuroimaging, EEG remains a valuable tool in the evaluation of stuporous and comatose patients. A systematic approach is essential for EEG interpretation, and when combined with good clinical judgment, it will improve diagnostic sensitivity and specificity and may improve therapeutic outcomes. This EEG atlas is designed as a practical guide for neurology residents, neurologists, and epileptologists, so that they may appropriately identify normal and abnormal findings, while reading an EEG. By reading and reviewing the relevant chapter of this well‐organized atlas, that includes many EEG images, the reader will also learn how to report an EEG finding. We hope that this atlas fills an unmet need, and leads to improved patient care.     

Developing of EEG Print and Its Preliminary Technical Application

In this report, we discuss a method called “EEG print” to represent EEG contrast mapping in time and frequency domains simultaneously. A bank of bandpass FIR (Finite Impulse Response) digital filters is used to obtain EEG prints. EEG prints were taken from four areas (F₃, F₄, O₁ and O₂) of EEG when healthy subjects were at rest with their eyes closed. The pattern of the prints was classified into four types: α type, β type, α+β type and complex type. It was found that EEG prints may vary from person-to-person but they usually do not vary much between the four areas for a given person. The method is further modified to obtain “differential EEG prints” to investigate whether meaningful higher frequency EEG components exist. Differentiation of EEG resulted in marked intensification of the fast waves, using 0.14 Hz as the critical point. In differential EEG print with higher order differentiation, amplification in the high frequency components increase their frequency. As a result, it is possible to observe variations in the high frequency components, which are otherwise not detectable in the usual EEG print. EEG print can be used for representing the function of the brain. Using the method for classification of EEG print patterns, described in this paper, we can clarify not only the characteristics of the normal brain but also the pathophysiology of mentally-ill patients.     

Assessment of hairline EEG as a screening tool for nonconvulsive status epilepticus

PURPOSE: Because of the high incidence of nonconvulsive status epilepticus (NCSE), the attraction of a "quick and easy" screening electroencephalogram (EEG) is obvious. Previous studies have shown utility of hairline EEG in diagnosing epilepsy. However, this technique has not been evaluated as a screening tool for NCSE. We wanted to provide proof of principle that a screening hairline EEG has sufficient sensitivity to use as a screening tool for diagnosing NCSE. METHODS: A total of 120, 2- to 3-min EEG samples of normal and various abnormal digital EEG studies were reformatted in three six-channel montages (A, longitudinal bipolar; B, referential to ipsilateral ear; C, referential to contralateral ear) that mimicked a hairline recording and were interpreted by five neurophysiologists. The test data interpretation was compared with the original EEG interpretation. RESULTS: Performance was best with montages A and B; 71% and 70.5% of the samples were interpreted correctly by using these montages. Only 65% of the samples were correctly interpreted by using montage C. With the best montage (A), the sensitivities ranged from 91% for normal EEG to 54% for periodic lateralized epileptiform discharges (PLEDs). The sensitivity for seizures was only 72%. Seizures were frequently misinterpreted as more benign patterns such as normal and diffuse slowing. CONCLUSIONS: EEG data reformatted to resemble a hairline EEG had low sensitivity for detecting seizures. As a result, we do not recommend further pursuit of hairline EEG as a "quick and easy" screening tool for NCSE.     

急性一氧化碳中毒后迟发性脑病的临床、脑电图、CT分析

目的 探讨一氧化碳中毒后迟发性脑病(DEACMP)的临床、脑电图(EEG)与头颅CT特点.方法 分析56例DEACMP患者的临床、脑电图与CT资料.结果 DEACMP患者的主要临床表现以急性痴呆为特征的神经精神症状及体征.脑电图表现异常率为100％,主要表现为α慢化或消失,弥漫性中高幅θ、δ波,以额或额颞部明显.昏迷时间越长EEG异常率越高,病情越重.头部CT表现为有病理性密度减低区;大脑皮质病变.结论 本病例诊断主要依靠病史、临床表现、EEG、及CT对判断预后有重要价值.     

水合氯醛对儿童癫痫异常脑电活动影响的研究

目的　探索水合氯醛 (chloralhydrate,CH)对儿童癫痫患者的镇静作用和诱导睡眠的效果 ,观测CH对异常脑电活动的影响。方法　口服 10 %CH ,记录给药前后的脑电图 (EEG)进行对比分析。结果　2 80例儿童癫痫 ,172例EEG无改变 (6 1.4 % ) ;75例异常波减少 (2 6 .8% ) ;33例异常波增多 (11.8% )。结论　CH是诱导儿童睡眠的最佳药物 ,虽在用药过程中出现短暂的轻微的EEG变化 ,但不影响EEG对癫痫的诊断结果。     

小儿手足口病并发脑炎的EEG诊断及对预后分析

目的探讨脑电图(electroencephalogram,EEG)对于小儿手足口病并发脑炎的应用及意义。方法回顾性分析103例临床确诊为小儿手足口病并发脑炎的患儿EEG的改变。结果本组EEG正常2.9%,异常率97.1%,主要表现为弥漫性慢波,部分出现阵发性尖(棘)波或尖(棘)-慢波。结论 EEG可作为小儿手足口病并发脑炎的诊断标准之一及判断小儿手足口病并发脑炎严重程度的价值指标;EEG的动态监测可作为小儿手足口病并发脑炎临床判断病情转归的一项指标。     

呕吐的脑电图检查与临床分析

目的探讨呕吐对脑功能的影响及脑电图（EEG）的改变。方法对250例呕吐患儿进行EEG观察。结果EEG广泛轻度异常119例（47．6％），广泛中度异常114例（45．6％），广泛重度异常17例（6.8％），治疗后EEG复查均有不同程度的好转。结论EEG检查对脑功能的损害程度和治疗评估有重要价值。     

64例急性CO中毒后迟发性脑病分析

目的：探讨DEACMP的临床转归、EEG演变规律及两者间的关系。方法对64例DEACMP病人进行临床观察，并对每1例病人进行两次以上EEG检查。结果DEACMP的临床演变规律是：急性CO中毒-假愈期-迟发脑病-迅速加重期-脑病稳定期-脑病恢复期-痊愈。DEACMP的EEG演变与病情演变是同步的。EEG随着脑病的加重而加重，随着脑病的恢复而好转。EEG检查的时期不同其结果也就不同。结论EEG检查尤其是动态观察EEG的演变对DEACMP的诊断、了解病情的严重程度以及脑病的恢复情况有重要价值。     

A standardised assessment scheme for conventional EEG in preterm infants

ObjectiveTo develop a standardised scheme for assessing normal and abnormal electroencephalography (EEG) features of preterm infants. To assess the interobserver agreement of this assessment scheme.MethodsWe created a standardised EEG assessment scheme for 6 different post-menstrual age (PMA) groups using 4 EEG categories. Two experts, not involved in the development of the scheme, evaluated this on 24 infants <32 weeks gestational age (GA) using random 2 hour EEG epochs. Where disagreements were found, the features were checked and modified. Finally, the two experts independently evaluated 2 hour EEG epochs from an additional 12 infants <37 weeks GA. The percentage of agreement was calculated as the ratio of agreements to the sum of agreements plus disagreements.ResultsGood agreement in all patients and EEG feature category was obtained, with a median agreement between 80% and 100% over the 4 EEG assessment categories. No difference was found in agreement rates between the normal and abnormal features (p = 0.959).ConclusionsWe developed a standard EEG assessment scheme for preterm infants that shows good interobserver agreement.SignificanceThis will provide information to Neonatal Intensive Care Unit (NICU) staff about brain activity and maturation. We hope this will prove useful for many centres seeking to use neuromonitoring during critical care for preterm infants.     

How wrong can we be? The effect of inaccurate mark-up of EEG/fMRI studies in epilepsy

ObjectiveThe aim of this investigation was to determine the effect of inaccurate or inconsistent marking up of events in the EEG on statistical analysis of EEG/fMRI studies of patients with epilepsy.MethodsEEGs obtained during EEG/fMRI studies conducted on 10 patients with epilepsy and six normal control subjects were reviewed. All clear epileptiform events were marked up in the patient EEGs, as were all small movement-related artefacts in the patient and control subject EEGs. We then considered the effect on the numbers of voxels above threshold in the resulting Statistical Parametric Mapping (SPM) analysis if events were omitted, mislabelled, or if event times were inconsistently marked up.ResultsOmitting true epileptiform events resulted in a decrease in the number of voxels that survive statistical threshold. Mixing epileptiform and non-epileptiform events in the SPM analysis generally (but not always) decreased the number of voxels that survived threshold. Inconsistent event mark-up had little effect if the inconsistency was small (<200 ms), but had more effect if it was large (>500 ms).ConclusionIt is important to accurately mark-up EEGs acquired during EEG/fMRI studies in order to get the best results from subsequent analyses.SignificanceOur study reveals the consequences of inaccurate review of the EEG in EEG/fMRI studies and suggests guidelines for the review of EEG in these investigations which, if followed, should result in studies of acceptable quality.     

长程脑电对癫痫外科术前定位的价值

目的 本研究为了确定长程脑电监测在癫痫外科术前定位、定侧作用。方法 对４０例顽固性癫痫患者进行术前普通脑电图（ＲＥＥＧ）、长程动态脑电图（ＡＥＥＧ）及术中皮质电图（ＥＣｏＧ）进行比较研究。结果 发现长程脑电监测对癫痫诊断的异常率、癫痫灶的定位率及手术定位率明显高于常规脑电图。但ＡＥＥＧ对精确定位不十分准确,结合术中皮质脑电图描记可以提供准确的手术部位和范围。结论 癫痫外科术前如有条件应该用长程脑电     

Spatio-temporal EEG power spectral patterns during a short daytime nap.

This is an approach to investigate topographic changes in electroencephalographic (EEG) spectral power during pre- and post-nap wakefulness as well as stages 1 (S1) and 2 (S2) NREM sleep in 12 subjects. Delta- and theta-band power significantly increased in the frontal and central regions during S1 and S2 with an increase in inter- and intra-hemispheric correlations. Beta-band power significantly increased in the frontal, central and parietal regions during S2 with an increase in interhemispheric correlation. In contrast, alpha-band power significantly decreased in the parietal-occipital regions during S1 and S2 with a decrease in interhemispheric correlation. Thus, daytime nap modulated spatio-temporal patterns of EEG power spectral patterns in wide scalp regions.     

Hemispheric quantitative EEG changes following emotional reactions in neurotic patients

Twenty-four right-handed patients undergoing primal therapy served as subjects in the study. They all showed symptoms of tension, anxiety, and/or depression. The patients’ right and left temporal EEGs were recorded immediately before and after a therapy session. Recordings were done while the patients were resting, and while they were performing a verbal and a visual task with their eyes closed. The EEG data were analyzed off-line with a computer, using quantitative amplitude analysis in the 1.5 to 30 Hz frequency band. A “high intensity” group (n= 13) having high ratings of emotional activity in their therapy session was compared with a “low intensity” group (n= 11) with low ratings. The results showed that only in the “high intensity” group was there a significant increase in mean amplitude and amplitude variance in the right hemisphere, measured across conditions. A between-group comparison revealed that the “high intensity” group showed a significantly larger increase in right hemisphere variance and in right over left variance ratio, relative to the “low intensity” group, in which these variables were almost unchanged. These results indicate a greater involvement of the right hemisphere in emotional activity. It is also suggested that the EEG changes found in the “high intensity” group, following a therapy session, reflect a general deactivation of the brain and a functional improvement of the right hemisphere.     

Cyclic seizures in critically ill patients: Clinical correlates,DC recordings and outcomes

Objective

To describe EEG and clinical correlates, DC recordings and prognostic significance of cyclic seizures (CS).