Development of amplitude-integrated electroencephalography and interburst interval in the rat

Continuous monitoring of electrocortical brain activity with amplitude-integrated electroencephalography (aEEG) is important in neonatology. aEEG is affected by, for example, maturity, encephalopathy, and drugs. Neonatal research uses rat pups of different ages. Postnatal day (P) 7 rats are suggested to be equivalent neurodevelopmentally to near-term infants. We hypothesized that electroencephalography (EEG) and aEEG in P1-P21 rats follow the same developmental pattern with respect to background activity and the longest interburst interval (IBI) as that seen in infants from 23-wk gestational age (GA) to post-term. We examined aEEG and EEG on 49, unsedated rat pups with two clinical monitors. aEEG traces were analyzed for lower and upper margin amplitude, bandwidth and the five longest IBI in each trace were measured from the raw EEG. The median longest IBI decreased linearly with age by 5.24 s/d on average. The lower border of the aEEG trace was <5 microV until P7 and rose exponentially reaching 10 microV by P12. This correlated strongly with the decrease in IBI; both reflect increased continuity of brain activity with postnatal age. Based on aEEG trace analysis, the rat aEEG pattern at P1 corresponds to human aEEG at 23-wk gestation; P7 corresponds to 30-32 wk and P10 to 40-42 wk.     

正常足月新生儿振幅整合脑电图特点的多中心研究

目的探讨正常足月新生儿生后3 d内振幅整合脑电图（aEEG）的特点,为新生儿临床脑功能监测提供依据。方法选择各参研医院母婴同室或新生儿室的正常足月新生儿为研究对象,依据胎龄分为37周～、38周～、39周～、40周～和41～42周胎龄组。采用首台国产aEEG仪记录正常足月新生儿生后1、2和3日龄的aEEG,每次记录3 h。采用半对数公式计算电压,分析正常足月新生儿aEEG背景波、电压、睡眠-觉醒周期及其影响因素。结果2008年5月至2009年5月纳入116名正常足月新生儿。①正常足月新生儿aEEG背景波呈现连续性波形。905％（105/116名）在生后1日龄出现睡眠-觉醒周期,所有正常足月新生儿在生后2日龄均出现睡眠-觉醒周期;②1个睡眠-觉醒周期的平均持续（699±187）min,其中宽带平均为（220±57）min,窄带平均为（479±171）min;③正常足月新生儿生后1、2和3日龄aEEG背景波最低电压分别为（128±34）、（121±20）和（125±26）μV,最高电压分别为（375±110）、（384±94）和（386±96）μV;④日龄、性别、分娩方式及母亲妊娠并发症对正常足月新生儿aEEG的宽带、窄带电压和时程均无显著影响,37周～胎龄组生后1～3日龄aEEG窄带电压上界较38～42周各胎龄组显著增高（P分别为0014,0001和0000）。结论正常足月新生儿aEEG背景波为连续波形,存在明显的睡眠-觉醒周期;最低电压均＞5 μV,最高电压均＞10 μV。37周～胎龄组的正常足月新生儿生后1～3日龄aEEG窄带电压上界较38～42周各胎龄组正常足月新生儿显著增高。正常足月新生儿的aEEG表现不受日龄、性别、分娩方式及母亲妊娠并发症的影响。     

Amplitude-integrated EEG pattern predicts further outcome in preterm infants

Changes in EEG background activity are powerful but nonspecific markers of brain dysfunction. Early EEG and amplitude-integrated EEG (aEEG) pattern predict further neurodevelopmental outcome in term infants; however, sufficient data for prognostic value of aEEG in preterm infants are not available so far. The aim of the study was to evaluate whether aEEG predicts further outcome and to compare it to cerebral ultrasound assessment. In 143 preterm infants, aEEG within the first 2 wk of life and outcome data at 3 y of age (Bayley Scales) could be obtained.aEEG was classified into a graded score according to background activity, appearance of sleep-wake cycling, and occurrence of seizure activity. In preterm infants, aEEG was significantly associated with further outcome. Specificity was 73% for assessment within the first and increased to 95% in the second week of life, whereas sensitivity stayed nearly the same 87% (first week) to 83% (second week). Cerebral ultrasound showed a specificity of 86% within the first and second week, sensitivity also stayed nearly the same (74 and 75%). aEEG has a predictive value for later outcome in preterm infants and can be used as an early prognostic tool.     

振幅整合脑电图对新生儿低血糖脑损伤患儿的脑功能监测意义

目的 探讨振幅整合脑电图(amplitude integrated electroencephalography,aEEG)在新生儿低血糖脑损伤急性期的改变以及其与疾病预后的相关性.方法 研究纳入2011年1月至2015年7月泉州市儿童医院新生儿重症监护室收治的47例新生儿低血糖脑损伤患儿.记录患儿的临床资料和治疗转归;采用aEEG进行脑功能监测;采用首都儿科研究所《0~6岁小儿神经心理发育检查表》进行患儿生后6月龄智能评估;分析aEEG背景活动分类,癫痫性电活动,睡眠觉醒周期,异常程度等参数与新生儿低血糖脑损伤患儿近期临床预后的相关性.结果 急性期aEEG波形:连续正常电压9例,不连续电压29例,连续低电压3例,爆发抑制6例;39例(83.0%)患儿记录到癫痫性电活动:单次惊厥、反复惊厥、惊厥持续状态分别为:11例、20例、8例;睡眠觉醒周期:无21例,不成熟17例,成熟9例.aEEG异常程度判定:正常7例,轻度异常9例,重度异常31例,其中重度异常中23例预后不良,包括死亡3例及随访至生后6月龄智能发育商≤69者20例.aEEG背景活动、睡眠觉醒周期分类以及aEEG异常程度与患儿临床近期预后通过双向有序等级相关性分析提示存在相关性(r=0.714、0.696、0.746,均P<0.001).结论 aEEG可以用于评估新生儿低血糖脑损伤患儿临床脑功能损伤严重程度及近期预后,是其脑功能监测的有用工具.     

The influence of extrauterine life on the aEEG maturation in normal preterm infants

Objective

To study, the maturational changes of the amplitude-integrated electroencephalogram (aEEG) in preterm infants without neurological disorders and especially the influence of the duration of extrauterine life, over this process.

Methods

96 preterm infants, 25-34 weeks' gestational age (GA) at birth, clinically stable and without ultrasonographic evidence of neurological abnormalities, were studied. The aEEG recordings were obtained within 72 h of life and then weekly until discharge. Four aspects of each tracing (continuity, sleep-wake cycling, bandwidth, and lower border), were evaluated by visual analysis, applying pre-established criteria.

Results

We analysed 624 aEEG recordings at postmenstrual age (PMA) of 25-42 weeks. With advanced GA the aEEG becomes more continuous (p: 0.022), it displays definite sleep-wake cycles (p: 0.011), and its bandwidth acquires the mature pattern (p: 0.012). A positive significant interaction of GA and PMA in the evolution of aEEG was found regarding continuity (p: 0.002), sleep-wake cycling (p: 0.002), and bandwidth (p: 0.02).

Conclusion

The evolution of the aEEG tracing depends on both GA and PMA. The older the infants at birth the more mature the aEEG pattern. At the same PMA, preterm infants of lower GA display an advanced maturation of the aEEG comparing with others of higher GA.     

Early single-channel aEEG/EEG predicts outcome in very preterm infants

Aim: To characterize early amplitude‐integrated electroencephalogram (aEEG) and single‐channel EEG (aEEG/EEG) in very preterm (VPT) infants for prediction of long‐term outcome. Patients: Forty‐nine infants with median (range) gestational age of 25 (22–30) weeks. Methods: Amplitude‐integrated electroencephalogram/EEG recorded during the first 72 h and analysed over 0–12, 12–24, 24–48 and 48–72 h, for background pattern, sleep–wake cycling, seizures, interburst intervals (IBI) and interburst percentage (IB%). In total, 2614 h of single‐channel EEG examined for seizures. Survivors were assessed at 2 years corrected age with a neurological examination and Bayley Scales of Infant Development‐II. Poor outcome was defined as death or survival with neurodevelopmental impairment. Good outcome was defined as survival without impairment. Results: Thirty infants had good outcome. Poor outcome (n = 19) was associated with depressed aEEG/EEG already during the first 12 h (p = 0.023), and with prolonged IBI and higher IB% at 24 h. Seizures were present in 43% of the infants and associated with intraventricular haemorrhages but not with outcome. Best predictors of poor outcome were burst‐suppression pattern [76% correctly predicted; positive predictive value (PPV) 63%, negative predictive value (NPV) 91%], IBI > 6 sec (74% correctly predicted; PPV 67%, NPV 79%) and IB% > 55% at 24 h age (79% correctly predicted; PPV 72%, NPV 80%). In 35 infants with normal cerebral ultrasound during the first 3 days, outcome was correctly predicted in 82% by IB% (PPV 82%, NPV 83%). Conclusion: Long‐term outcome can be predicted by aEEG/EEG with 75–80% accuracy already at 24 postnatal hours in VPT infants, also in infants with no early indication of brain injury.     

Use of antenatal steroids to counteract the negative effects of tracheal occlusion in the fetal lamb model

Total and regional cerebral glucose metabolism (CMRgl) was measured by positron emission tomography with 2-((18)F) fluoro-2-deoxy-D-glucose ((18)FDG) in 20 term infants with hypoxic ischemic encephalopathy (HIE) after perinatal asphyxia. All infants had signs of perinatal distress, and 15 were severely acidotic at birth. Six infants developed mild HIE, twelve moderate HIE, and two severe HIE during their first days of life. The positron emission tomographic scans were performed at 4-24 d of age (median, 11 d). One hour before scanning, 2-3.7 MBq/kg (54-100 microCi/kg) (18)FDG was injected i.v. No sedation was used. Quantification of CMRgl was based on a new method employing the glucose metabolism of the erythrocytes, requiring only one blood sample. In all infants, the most metabolically active brain areas were the deep subcortical parts, thalamus, basal ganglia, and sensorimotor cortex. Frontal, temporal, and parietal cortex were less metabolically active in all infants. Total CMRgl was inversely correlated with the severity of HIE (p < 0.01). Six infants with mild HIE had a mean (range) CMRgl of 55.5 (37.7-100.8) micromol.min(-1).100 g(-1), 11 with moderate HIE had 26.6 (13.0-65.1) micromol.min(-1).100 g(-1), and two with severe HIE had 10.4 and 15.0 micromol.min(-1).100 g(-1), respectively. Five of six infants who developed cerebral palsy had a mean (range) CMRgl of 18.1 (10.2-31.4) micromol.min(-1).100 g(-1) compared with 41.5 (13.0-100.8) micromol.min(-1).100 g(-1) in the infants with no neurologic sequela at 2 y. We conclude that CMRgl measured during the subacute period after perinatal asphyxia in term infants is highly correlated with the severity of HIE and short-term outcome.     

早产儿振幅整合脑电图的影响因素

目的探讨早产儿振幅整合脑电图(aEEG)的影响因素。方法在出生12 h内采用NicoletOne脑功能监测仪对71例早产儿进行aEEG描记。根据aEEG背景活动的方式及有无惊厥样活动,将aEEG结果判断为正常和异常aEEG(包括轻度异常及重度异常)。床旁颅脑超声监测脑损伤的发生。分析胎龄、出生体质量、窒息、低氧血症、辅助通气及脑损伤对早产儿aEEG的影响。结果 1.早产儿71例中,正常aEEG 40例,异常aEEG 31例。2.胎龄<34周者54例,正常aEEG 25例,异常aEEG 29例(53.7%);≥34周者17例,正常aEEG 15例,异常aEEG 2例(11.8%);2组aEEG异常率比较差异有统计学意义(χ2=9.245 2,P<0.01)。3.出生体质量<1.5 kg者25例,正常aEEG 8例,异常aEEG 17例(68.0%);出生体质量≥1.5 kg者46例,正常aEEG 32例,异常aEEG14例(30.4%);2组aEEG异常率比较差异有统计学意义(χ2=9.291 9,P<0.001)。4.产时有窒息者36例,正常aEEG 15例,异常aEEG 21例(58.3%);无窒息者35例,正常aEEG 25例,异常aEEG 10例(28.6%);2组aEEG异常率比较差异有统计学意义(χ2=6.390 4,P<0.05)。5.低氧血症24例,正常aEEG 16例,异常aEEG 8例(33.3%);无低氧血症者47例,正常aEEG 24例,异常aEEG 23例(48.9%);2组aEEG异常率比较差异无统计学意义(χ2=1.572 4,P>0.05)。6.辅助通气者19例,正常aEEG 8例,异常aEEG 11例(57.9%);未辅助通气者52例,正常aEEG 32例,异常aEEG 20例(38.5%);2组aEEG异常率比较差异无统计学意义(χ2=2.136 4,P>0.05)。7.有脑损伤者51例,正常aEEG 24例,异常aEEG 27例(52.9%);无脑损伤者20例,正常aEEG 16例,异常aEEG 4例(20.0%);2组aEEG异常率比较差异有统计学意义(χ2=6.337 5,P<0.05)。结论胎龄和出生体质量对早产儿aEEG有显著影响。小胎龄、低出生体质量以及出生时窒息和脑损伤的早产儿异常aEEG的发生率高。在分析早产儿aEEG时应考虑胎龄、出生体质量、窒息及脑损伤等生理病理因素的影响。     

The prognostic value of amplitude integrated EEG in neonatal sepsis and/or meningitis

Aim: To investigate the longitudinal course and prognostic value of amplitude integrated EEG (aEEG) in infants with neonatal sepsis or meningitis. Methods: Amplitude integrated EEG recordings of 22 infants with sepsis/meningitis were retrospectively evaluated. Mean gestational age was 38 weeks (range: 34–42 weeks). Thirteen infants had meningitis. Survivors were seen for neurological follow‐up. Four infants died, two were severely abnormal at 24 months. Amplitude integrated EEG background pattern, sleep wake cycling (SWC) and electrographic seizure activity (EA) were appraised. Results: All infants with continuous low voltage or flat trace on aEEG (n = 4) had an adverse outcome. Low voltage aEEGs (n = 9) had a positive LR (LR+) for an adverse outcome of 5.3 (95% CI: 1.9–14.8) at 6 h and 8.3 (95% CI: 1.3–55) at 24 h after admission. EA was more frequent in infants with adverse outcome (p < 0.01) and had a LR+ for adverse outcome of 10.6 (95% CI: 1.5–76). SWC appeared more frequent in infants with good outcome (p < 0.05). Conclusion: Low voltage background pattern, SWC and EA on aEEG are helpful to predict neurological outcome in infants with neonatal sepsis or meningitis.     

Amplitude integrated electroencephalographic activity in infants with congenital heart disease before surgery

Background

Infants with congenital heart disease (CHD) are at risk for brain injury. An accurate tool to monitor brain function is amplitude integrated EEG (aEEG). It records both background patterns and electrographic seizure activity (EA).

Aims

Our aim was to determine aEEG patterns in infants with CHD and to determine the differences between infants with a cyanotic or an acyanotic CHD.

Study design and subjects

Sixty-two full term newborns had either a cyanotic CHD (transposition of the great arteries (n = 24)) or an acyanotic CHD (hypoplastic left heart syndrome (n = 26), critical aortic valve stenosis (n = 1) or aortic coarctation (n = 11)). The background patterns, sleep-wake cycling (SWC), and EA were assessed. The first 72 h after starting prostaglandin E₁-therapy were used for analysis.

Results

The background patterns were mildly abnormal in 45% of the infants and severely abnormal at some point during the recording in 14% of the infants. We found no differences in background patterns between the two groups. EA was present in 12 (19%) infants. EA was more frequent in infants with acyanotic CHD (OR 9.4, 95% CI 1.1-78, p = 0.039). SWC was equally frequent in infants with cyanotic and infants with acyanotic CHD. A severely abnormal aEEG and EA were associated with more profound acidosis.

Conclusions

Before surgery the majority of infants with a CHD had an abnormal aEEG. aEEG helped to identify EA and it was a useful tool to evaluate brain function prior to surgery in CHD.     

正常早产儿振幅整合脑电图特点的研究

目的 了解28 ～ 36周正常早产儿出生时振幅整合脑电图(Amplitude integrated Electroencephalogram,aEEG)特征,为早产儿临床脑功能监测提供依据。方法 共纳入胎龄28～ 36周早产儿135例,采用国产数字化振幅整合脑功能监护仪（CFM3000,样机）分别于生后3d内进行监测,每次连续监测4h。分析正常28～36周早产儿aEEG背景连续性、睡眠-觉醒周期（周期性）、电压和带宽。结果 连续性电压由28周的30％增加至36周时的85.7％(x2=28.2,P=0.026)。睡眠-觉醒周期出现率由28周的10％增加至36周时的100％( x2=192.4,P＜0.01)。窄带下界电压由28周的(6.8±1.7) μV升至35～36周的9.7～10.1 μV(F=11.4,P＜0.01)。窄带带宽由28周的(21.3 ±8.3)μV降至36周的(14.9±7.5) μV(F =8.731,P=0.000)。aEEG连续性、周期性、窄带带宽和总评分与胎龄的相关系数分别为0.32、0.81、0.55和0.78,P均＜0.05,窄带下界电压（μV）与胎龄的相关系数为0.38,P＜ 0.05。结论出生时胎龄越大,aEEG越成熟,表现为aEEG图形的连续性、睡眠-觉醒周期渐趋明显,窄带下界电压逐渐升高,带宽变窄。     

振幅整合脑电图监测不同胎龄早产儿宫外环境下脑发育的多中心观察性研究

目的 了解宫外生活对28~36周早产儿振幅整合脑电图（aEEG）的影响。方法 以出生时无窒息抢救史早产儿为早产儿组,以胎龄37周出生后正常的新生儿为对照组;早产儿组采用振幅整合脑电图仪分别于生后3 d内,然后每周监测1次直至出院（或最长监测至纠正胎龄37周）,对照组于生后第3 d 行aEEG监测。每次连续监测4 h。分析胎龄和纠正胎龄对aEEG成熟过程影响,包括aEEG背景连续性、睡眠-觉醒周期、下边界振幅和带宽。5家参研医院均采用相同品牌和型号的aEEG,研究开始前统一进行操作技术培训,样本的临床和图像数据发送至复旦大学附属儿科医院整理。结果 2008年5月1日至2009年8 月31日5家参研医院符合本文纳入和排除标准的早产儿组135例,对照组20例。早产儿aEEG的成熟度受胎龄和纠正胎龄的影响,随胎龄和纠正胎龄增加,aEEG背景连续性和睡眠-觉醒周期出现的百分比均增加,逐步出现连续性电压（χ2=26.865,P<0.01）,≥34周出生的早产儿成熟的睡眠-觉醒周期的出现的百分比均为100％（χ2=192.4,P<0.01）;下边界振幅升高（F＝11.4,P<0.01）,带宽变窄（F＝8.731,P<0.01）。纠正胎龄和同出生胎龄的新生儿比较,连续性电压百分比、睡眠-觉醒周期的出现率均显著增加,胎龄＞34周的早产儿出生时aEEG均可见明显的睡眠-觉醒周期,而纠正胎龄32周时,睡眠-觉醒周期出现的百分比已达到100%;窄带下界也显著增高;窄带带宽变窄,至34周龄后,纠正胎龄和同出生胎龄新生儿均变化不明显。结论 早产儿aEEG的成熟度与出生胎龄和纠正胎龄相关,宫外生活加速了早产儿脑发育成熟。     

Background patterns and sleep-wake cycles on amplitude-integrated electroencephalography in preterms younger than 30 weeks gestational age with peri-/intraventricular haemorrhage

AIM: The objective of this prospective study was to evaluate the influence of peri-/intraventricular haemorrhage (PIVH) grades I-IV on amplitude-integrated electroencephalographic (aEEG) activity in preterm infants<30 weeks gestational age (GA). METHODS: The aEEG tracings of the first 2 weeks of life of 56 preterm infants younger than 30 weeks GA (2 groups: group A=23-26 weeks GA, group B=27-29 weeks GA) born during a 4-year period with PIVH grades I-IV were assessed for the relative duration of four background aEEG activity patterns (continuous pattern, discontinuous high-voltage pattern, discontinuous low-voltage pattern and nearly isoelectric pattern), the presence of seizure activity and the appearance of sleep-wake cycles and compared to the tracings of 75 neurologically healthy preterms without PIVH. RESULTS: Analysis of aEEG background activity showed a decrease of continuous activity whereas discontinuous activity increased in both groups with larger haemorrhages (grades III and IV) and when compared to controls. Suspected seizure activity was more common with increasing degree of bleeding in group A (50% with PIVH I or II, 75% with PIVH III or IV) and when compared to controls and was the same with increasing degree of bleeding in group B (47% with PIVH I or II, 45% with PIVH III or IV). Sleep-wake cycles were less common with larger haemorrhages in both groups (group A: 41% with PIVH I or II, 25% with PIVH III or IV; group B: 52% with PIVH I or II, 9% with PIVH III or IV) and when compared to controls. CONCLUSIONS: The aEEG characteristics of severe PIVH consist in a combination of a more discontinuous background pattern, a lack of sleep-wake cycles and a higher likelihood of seizure activity when compared to age-matched controls.     

Prognostic significance of amplitude-integrated EEG during the first 72 hours after birth in severely asphyxiated neonates

Amplitude-integrated EEG (aEEG) is used to select patients for neuroprotective therapy after perinatal asphyxia because of its prognostic accuracy within several hours after birth. We aimed to determine the natural course of aEEG patterns during the first 72 h of life, in relation to neurologic outcome, in a group of severely asphyxiated term infants. Thirty infants, admitted to our neonatal intensive care unit from October 1998 until February 2001, were studied retrospectively. The aEEG traces obtained during the first 72 h after birth were assessed by pattern recognition: continuous normal voltage (CNV), discontinuous normal voltage (DNV), burst suppression (BS), continuous low voltage, and flat trace. Epileptic activity was also determined. The course of aEEG patterns was examined in relation to neurologic findings at 24 mo. Initially, 17 of 30 infants had severely abnormal aEEG patterns (BS or worse), which changed spontaneously to normal voltage patterns (CNV, DNV) in 7 within 48 h. The sooner the abnormalities on aEEG disappeared, the better the prognosis. The likelihood ratio of BS or worse for adverse outcome was 2.7 (95% confidence interval 1.4-5.0) between 0 and 6 h and increased to a highest value of 19 (95% confidence interval 2.8-128) between 24 and 36 h; after 48 h, it was not significant. Normal voltage patterns (CNV and DNV) up to 48 h of life were predictive for normal neurologic outcomes (negative likelihood ratios <0.3). Our findings indicate that the course of aEEG patterns adds to the prognostic value of aEEG monitoring in asphyxiated infants. Spontaneous recovery of severely abnormal aEEG patterns is not uncommon.     

Amplitude-integrated electroencephalography for seizure detection in newborn infants

The amplitude-integrated electroencephalogram (aEEG) is a filtered and compressed EEG trend that can be used for long-term monitoring of brain function in patients of all ages. aEEG is increasingly used in neonatal intensive care units since several studies have shown its utility in high-risk newborn infants. Main indications for aEEG monitoring include early evaluation of brain function after perinatal asphyxia and seizure detection. The aEEG is usually recorded from one or two channels derived from parietal, central, or frontal leads. Although the aEEG is very useful for identifying high-risk infants and infants with seizures, the compressed trend has limitations with regards to detection of individual seizures. However, modern monitors also display the corresponding EEG (aEEG/EEG), which increases the probability of detecting single brief seizures. For improved evaluation of electrocortical brain activity the aEEG/EEG should be assessed together with repeated conventional EEGs or multi-channel EEG monitoring in a multi-disciplinary team.     

Lack of influence of mild hypothermia on amplitude integrated-electroencephalography in neonates receiving extracorporeal membrane oxygenation

OBJECTIVE: To observe amplitude integrated electroencephalography (aEEG) in neonates receiving ECMO and to determine whether mild hypothermia influenced the aEEG recording. METHODS: Twenty-six consecutive neonates enrolled in a pilot study of mild hypothermia during ECMO were studied. The first group (N=6) was maintained at 37 degrees C throughout the study period. Subsequent groups were cooled to 36 degrees C (N=4), 35 degrees C (N=5), and finally 34 degrees C (N=6) respectively for 24 h and the final group (N=5) to 34 degrees C for 48 h before being rewarmed to 37 degrees C. The aEEG was recorded continuously during the first 5 days of ECMO. The aEEG was classified as normal, moderately or severely suppressed and examined for the occurrence of seizures. To assess the effect of temperature, the aEEG was compared over 12 h during the final 6 h of cooling and during the first 6 h once infants were rewarmed. RESULTS: No change in aEEG amplitude was noted over the temperature range studied. Of the 26 traces obtained, 16 (62%) were normal throughout, 6 (23%) were intermittently moderately abnormal and 1 (14%) was severely abnormal. Three (11%) traces had periods of frequent seizure activity and these were not associated with clinical manifestations in two neonates. In one infant who suffered a cerebral haemorrhage, the aEEG became abnormal before cranial ultrasound abnormalities were apparent. CONCLUSIONS: Continuous cerebral monitoring with aEEG is feasible during ECMO and may add information to clinical examination. Mild hypothermia to 34 degrees C for up to 48 h does not influence the aEEG suggesting that cerebral monitoring with aEEG is possible during mild hypothermia.     

Predictive value of early continuous amplitude integrated EEG recordings on outcome after severe birth asphyxia in full term infants.

The background pattern in single channel amplitude integrated EEG recordings (aEEG) was recorded in 47 infants within the first six hours after birth to see if this could predict outcome after birth asphyxia. The aEEG background pattern during the first six hours of life was continuous and of normal voltage in 26 infants. All these infants survived; 25 were healthy, one had delayed psychomotor development. A continuous but extremely low voltage pattern was present in two infants, both of whom survived with severe handicap. Five infants had flat (mainly isoelectric) tracings during the first six hours of life; four died in the neonatal period, and one survived with severe neurological handicap. Burst-suppression pattern was identified in 14 infants, of whom five died, six survived with severe handicap, and three were healthy at follow up. The type of background pattern recorded within the first six postnatal hours in the aEEG tracings predicted outcome correctly in 43 of 47 (91.5%) infants. Use of aEEG monitoring can predict outcome, with a high degree of accuracy, after birth asphyxia, within the first six hours after birth. The predictive value of a suppression-burst pattern was, however, somewhat lower than the other background patterns. The aEEG seems to be a feasible technique for identifying infants at high risk of subsequent brain damage who might benefit from interventionist treatment after asphyxia.     

Effects of magnesium sulphate on amplitude-integrated continuous EEG in asphyxiated term neonates

In this study it is hypothesized that magnesium sulphate in asphyxiated full-term neonates could lead to a gradual improvement in background pattern of the amplitude integrated EEG (aEEG), an early marker of hypoxic-ischaemic brain injury. In a double-blind, randomized, controlled pilot study of 22 asphyxiated full-term neonates 8 received magnesium sulphate, reaching serum Mg2+ levels of 2.5 mmol/L. Magnesium sulphate had no immediate effect on aEEG-patterns. At 12 h of age, aEEG was more depressed compared with aEEG at 3 h in 6 of the 8 magnesium-treated neonates, and in 3 of the 14 placebo-treated neonates (Mg2+ vs placebo: p < 0.05, Mann-Whitney). No further significant changes in aEEG were seen between 12 and 24 h. Outcome was unfavourable in 4 of the 8 magnesium-treated neonates, and in 8 of the 14 placebo-treated neonates. Conclusion: Magnesium sulphate did not have a positive effect on aEEG patterns in this small group of asphyxiated term neonates.     

Early markers of brain damage in premature low-birth-weight neonates who suffered from perinatal asphyxia and/or infection

We studied 57 low-birth-weight premature neonates, of whom 29 suffered from perinatal asphyxia and/or infection, while the remaining 28 did not and served as controls. We measured peripheral nucleated red blood cell (NRBC) absolute numbers as well as interleukin (IL)-1beta, IL-6 and tumour necrosis factor (TNF)-alpha cytokine serum levels at 24 h postnatally and on days 3 and 7 following birth. Fourteen of the asphyxiated/infected neonates and 12 controls had neurologic assessments at the corrected postnatal age of 18 months. We found NRBC absolute numbers and serum IL-1beta and IL-6 cytokine levels at 24 h postnatally to be significantly higher in neonates with perinatal asphyxia/infection than in the controls (p = 0.022, p = 0.036 and p = 0.037, respectively). TNF-alpha levels did not differ. Neurologic examination at the corrected postnatal age of 18 months showed 8 out of the 14 children who had been asphyxiated/infected as neonates to have abnormal findings, while 12 children who were used as controls during their neonatal period were normal. Abnormal neurologic findings correlated with high NRBC counts and IL-1beta and IL-6 levels at 24 h postnatally. In conclusion, increased NRBC counts and proinflammatory cytokine levels in asphyxiated/infected neonates represent early markers for subsequent neurologic impairment.     

Developmental change of amplitude-integrated electroencephalographic activity in preterm infants with intraventricular hemorrhage

Background

Amplitude-integrated electroencephalography (aEEG) allows continuous brain function monitoring at bedside.

Objectives

This prospective cohort study was designed to longitudinally evaluate aEEG tracings at increased postmenstrual age (PMA) in preterm infants with intraventricular hemorrhage (IVH).

Methods

Biweekly aEEG recordings were performed on preterm infants < 32 weeks gestational age from 24 to 36 weeks PMA. The tracings were evaluated according to a scoring system adapted from Burdjalov et al.

Results

We analyzed 496 aEEG recordings in 105 preterm infants. The control group consisted of 42 infants with no IVH, whereas the IVH grade I, II, III, and IV groups consisted of 38, 8, 3, and 14 infants, respectively. There were significant differences in the cycling and total maturation scores among the IVH groups at 36 weeks PMA (p = 0.010 and p = 0.006, respectively). The IVH-IV patients maintained low scores in their cycling as their PMA increased, in contrast to their continuity and amplitude scores. The risk factors affecting the aEEG maturation scores at 36 weeks PMA in the IVH-IV patients included seizure events with the administration of antiepileptic drugs and the insertion of external ventricular drains (β = − 0.679 and β = − 0.418, respectively; p = 0.003).

Conclusions

The low cycling scores persisted until 36 weeks PMA in the IVH-IV group.