Amplitude-integrated electroencephalography shows mild delays in electrocortical activity in preterm infants born small for gestational age

Electroencephalographic studies in growth-restricted and small-for-gestational-age neonates

Foetal growth restriction (FGR) and being born small for gestational age (SGA) are associated with neurodevelopmental delay. Early diagnosis of neurological damage is difficult in FGR and SGA neonates. Electroencephalography (EEG) has the potential as a tool for the assessment of brain development in FGR/SGA neonates. In this review, we analyse the evidence base on the use of EEG for the assessment of neonates with FGR or SGA. We found consistent findings that FGR/SGA is associated with measurable changes in the EEG that present immediately after birth and persist into childhood. Early manifestations of FGR/SGA in the EEG include changes in spectral power, symmetry/synchrony, sleep-wake cycling, and the continuity of EEG amplitude. Later manifestations of FGR/SGA into infancy and early childhood include changes in spectral power, sleep architecture, and EEG amplitude. FGR/SGA infants had poorer neurodevelopmental outcomes than appropriate for gestational age controls. The EEG has the potential to identify FGR/SGA infants and assess the functional correlates of neurological damage. IMPACT: FGR/SGA neonates have significantly different EEG activity compared to AGA neonates. EEG differences persist into childhood and are associated with adverse neurodevelopmental outcomes. EEG has the potential for early identification of brain impairment in FGR/SGA neonates.

Prophylactic Low-Dose Paracetamol Administration for Ductal Closure and Amplitude-Integrated Electroencephalography in Preterm Infants

INTRODUCTION

Prophylactic low-dose paracetamol administration is used to induce closure of the ductus arteriosus in preterm infants. In our recent study we found no impairment on microstructural maturation processes in the brain of preterm infants at term-equivalent age following prophylactic low-dose paracetamol administration. We now assessed amplitude-integrated electroencephalography (aEEG) signals in preterm infants with and without exposure to prophylactic low-dose paracetamol administration.

METHODS

Infants <32 gestational weeks born between 10/2014 and 12/2018 received prophylactic paracetamol (10 mg/kg intravenously every 8 h until echocardiography after at least 72 h) and form the paracetamol group; infants born between 02/2011 and 09/2014 formed the control group. Four single parameters (continuity, cyclicity, amplitude of lower border, bandwidth span) together with their sum (Burdjalov total score) and presence of sleep-wake cycles were compared between the groups.

RESULTS

Included in the study were 338 infants. Two-hundred and seventeen infants received prophylactic paracetamol and 121 formed the control group. The paracetamol group showed a significantly higher number of sleep-wake cycles per hour and a significantly higher total scores compared to the control group (p < 0.05).

CONCLUSION

Paracetamol exposure has been regarded critically with respect to safety in preterm infants in recent years. We found no impairment on amplitude-integrated electroencephalography signals in preterm infants receiving low-dose prophylactic paracetamol compared to controls. Growing awareness and greater availability of data may encourage the clinicians to administer prophylactic paracetamol for ductal closure in preterm infants. The clinical relevance of our findings has to be evaluated in long-term follow up studies on neurodevelopmental outcome.

Amplitude-integrated electroencephalography signals in preterm infants with cerebral hemorrhage

OBJECTIVE

To evaluate whether preterm infants with cerebral hemorrhage show alterations of aEEG signals in the first four weeks of life.

STUDY DESIGN

Preterm infants (n = 536) born before 32 completed weeks of pregnancy at Innsbruck Medical University Hospital were included in the study. AEEG recordings were evaluated for the Burdjalov score and cerebral hemorrhage was diagnosed by cerebral ultrasound.

RESULTS

Eighty preterm infants with cerebral hemorrhage (median gestational age 28.9 weeks, median birth weight 1157 g) and 456 preterm infants without cerebral hemorrhage (median gestational age 30.0 weeks, median birth weight 1300 g) were investigated. Burdjalov total scores were significantly lower in infants with cerebral hemorrhage. Infants with mild cerebral hemorrhage showed higher Burdjalov total scores compared to infants with severe cerebral hemorrhage in the first days of life. A Burdjalov total score of seven or more was predictive for no development of a cerebral hemorrhage, with a highest area under the curve (0.613) at postnatal day three.

CONCLUSION

Preterm infants with cerebral hemorrhage show alterations in aEEG signals in the newborn period. In future aEEG could be used as a supplemental method to monitor preterm infants at risk for cerebral hemorrhage. The use of aEEG in early life could reduce the number of ultrasound examinations and limit cumulative stress and discomfort in preterm infants.

[Clinical significance of amplitude-integrated electroencephalography in preterm infants with bronchopulmonary dysplasia]

OBJECTIVE

To study the changes and clinical significance of amplitude-integrated electroencephalography (aEEG) in preterm infants with bronchopulmonary dysplasia (BPD).

METHODS

A total of 156 preterm infants with a gestational age of ≤ 32⁺⁶ weeks who were diagnosed with BPD were enrolled as the BPD group, and 156 preterm infants without BPD who were hospitalized during the same period of time were enrolled as the control group. The aEEG scoring system for preterm infants was used to compare aEEG results between the two groups during hospitalization. A stratified analysis was conducted based on the examination time (at the corrected gestational age of ≤ 28⁺⁶ weeks, 29-30⁺⁶ weeks, 31-32⁺⁶ weeks, 33-34⁺⁶ weeks, 35-36⁺⁶ weeks, and 37-38⁺⁶ weeks).

RESULTS

Compared with the non-BPD group, the BPD group had a significantly lower total aEEG score at the corrected gestational age of 33-34⁺⁶ weeks (P < 0.001). The mild BPD group had a significantly lower total aEEG score than the non-BPD group at the corrected gestational age of 33-34⁺⁶ weeks (P < 0.05); the moderate BPD group had a significantly lower total aEEG score than the non-BPD group at the corrected gestational ages of 31-32⁺⁶ weeks, 33-34⁺⁶ weeks, and 35-36⁺⁶ weeks (P < 0.05); the severe BPD group had a significantly lower total aEEG score than the non-BPD group at all corrected gestational ages except ≤ 28⁺⁶ weeks and 29-30⁺⁶ weeks (P < 0.05).

CONCLUSIONS

Preterm infants with BPD (especially moderate to severe BPD) have a lower aEEG score than those without BPD, suggesting that their nervous system development may lag behind that of non-BPD preterm infants with the same gestational age. Therefore, early nervous system evaluation and intervention are necessary for preterm infants with BPD.

Evaluation of maturity of sleep states in preterm infants using conventional and amplitude-integrated electroencephalography

OBJECTIVE

To determine whether sleep state maturity can be estimated accurately using conventional electroencephalography (cEEG) or amplitude-integrated electroencephalography (aEEG) features concerning sleep in neurologically unimpaired preterm infants.

METHODS

A total of 51 preterm infants were monitored with cEEG-polygraphy and simultaneous aEEG. Sleep state maturity of EEG corresponded to specific postmenstrual age (PMA). PMA on cEEG was blindly estimated according to cEEG patterns (indicated as background continuity, frequencies, and voltages) as well as developmental markers in specific states. PMA on aEEG was blindly estimated based on the cycling score (cycling representing sleep state transitions) according to a pre-established scoring system.

RESULTS

A total of 51 EEGs recorded between 32 and 37 weeks PMA were analysed. A significant relationship between estimated PMA (ePMA) and actual chronological PMA (cPMA) was shown by linear regression both on cEEG (r = 0.93, β = 0.98, 95% confidence interval (CI) 0.87-1.09, p < 0.001) and aEEG (r = 0.85, β = 0.83, 95% CI 0.69-0.98, p < 0.001). The estimation gap (defined as ePMA minus cPMA) was between -2 and +2 weeks both on cEEG and aEEG. The percentage of estimation gap between -1 and +1 weeks was 96% for cEEG, which was higher than the estimate of 88% for aEEG.

CONCLUSION

Estimated maturity of sleep state was well correlated with cPMA both on cEEG and aEEG. PMA corresponding to state maturity could be estimated within two weeks of actual cPMA using either of these two tools. However, cEEG had higher accuracy compared with aEEG in the evaluation of sleep state maturity.

Early preterm infants with abnormal psychomotor neurodevelopmental outcome at age two show alterations in amplitude-integrated electroencephalography signals

INTRODUCTION

Recent studies showed that neurodevelopment in preterm infants can be predicted by using amplitude-integrated electroencephalography (aEEG)-derived parameters. In our previous study we demonstrated that aEEG could be useful in predicting neurodevelopmental outcome in very preterm infants at the corrected age of 2 years.

AIM

The aim of this study was to further evaluate aEEG for predicting neurodevelopmental outcome at the at the corrected age of 2 years in preterm infants.

METHODS

Between July 2010 and June 2016 440 very preterm infants were eligible for the study at Innsbruck Medical University Hospital. The aEEG was evaluated for the Burdjalov score in 306 preterm infants (mean gestational age 29.5 weeks; range: 24.1-31.9 weeks). At the corrected age of 2 years outcome was assessed by the Bayley Scales of Infant and Toddler Development.

RESULTS

The cohort was divided into three subgroups: 248 infants with normal outcome, 40 infants with delayed outcome and 18 infants with abnormal outcome. Burdjalov scores were lower in infants with delayed outcome than in infants with normal outcome and even lower in infants with abnormal outcome. Post-hoc analysis showed significant differences between normal and delayed psychomotor outcome at 18-24 h (5 (3;6) versus 3 (3;5), p = .024), 30-36 h (6 (4;8) versus 4 (4;6), p = .033), 42-48 h (7 (5;8.5) versus 4 (4;7), p = .003), 54-60 h (7 (6;9) versus 5 (4;7), p = .003), 66-72 h (8 (6;9) versus 6.5 (4.25;7.75), p = .027) and week one (8 (7;10) versus 6.5 (5;8), p = .021). Additionally, when comparing normal to abnormal outcome, a significant difference was found at week four (12 (9;12) versus 8 (7;10), p = .024). The Burdjalov score was only predictive for a delayed psychomotor outcome, presenting the highest area under the curve (0.690) at week two of life.

CONCLUSION

We observed differences in aEEG signals and neurodevelopmental outcome at the corrected age of 2 years, especially for psychomotor outcome. The predictive value of the Burdjalov score regarding neurodevelopmental outcome at the corrected age of 2 years in preterm infants was low.

Amplitude-Integrated EEG and Brain Sparing in Preterm Small-for-Gestational-Age Infants

PURPOSE

Preterm small-for-gestational-age (SGA) infants are at risk for a high mortality rate and impaired cognitive development. Only a few studies have focused on amplitude-integrated EEG (aEEG) in preterm SGA infants. They have been shown to have a slower rate of brain maturation, but these findings have not consistently been related to neurodevelopmental outcomes. The aim of our study was to evaluate early aEEG monitoring in SGA compared with adequate-for-gestational-age preterms.

METHODS

This prospective cohort study enrolled infants with very low birth weight who were admitted to the neonatal intensive care unit at Hospital Puerta del Mar, Cádiz, Spain, from June 2009 to September 2012. This study was a subanalysis of SGA from the global cohort previously described by our group. Adverse outcome included severe intraventricular hemorrhage and/or death. Cerebral function was monitored using aEEG recordings during the first 72 hours of life.

RESULTS

Preterm SGA infants (18 SGA in the global cohort of 92 patients) had lower 1- and 5-minute Apgar scores, higher score for neonatal acute physiology perinatal extension II scores, and higher proportion of adverse outcomes. When comparing preterm adequate-for-gestational-age infants with SGA infants with good prognosis, those with SGA had more mature and continuous aEEG patterns. Low margin amplitude depression was not as severe in these patients, and a higher proportion of these patients developed sleep-wake cycles.

CONCLUSIONS

The results of our study suggest that SGA infants with a good prognosis have a more mature aEEG pattern than preterm adequate-for-gestational-age patients with the same outcome. These findings support the brain sparing theory in SGA infants.

Amplitude-integrated electroencephalography can predict neurodevelopmental outcome at 12 months of corrected age in very preterm infants

AIM

It is difficult to find diagnostic tools than can reliably predict neurodevelopmental outcomes in very preterm infants in clinical practice. This study evaluated whether amplitude-integrated electroencephalography predicted neurodevelopmental outcome in preterm infants when they reached 12 months of corrected age.

METHODS

Between October 2007 and December 2013, we studied 232 preterm infants (51% male) at Innsbruck Medical University Hospital, Austria. Their mean birthweight was 1264 g, and their mean gestational age was 29.5 weeks. Amplitude-integrated electroencephalography was evaluated using the Burdjalov score, and outcomes were assessed using the Bayley Scales of Infant Development - Second Edition.

RESULTS

The cohort was divided into three subgroups: 154 infants with normal outcomes, 53 infants with moderate delays and 25 infants with severe delays. The amplitude-integrated electroencephalography Burdjalov scores were lower in infants with moderate delays than in infants with normal outcomes and even lower in infants with severe delays. The highest area under the curve (0.776) for the Burdjalov score was at 18-24 hours of life.

CONCLUSION

Our study confirmed the predictive value of amplitude-integrated electroencephalography and showed that this needed to be carried out early in life to provide reliable information on neurodevelopmental outcomes in very preterm infants.

Comparison of two common aEEG classifications for the prediction of neurodevelopmental outcome in preterm infants

Neurodevelopmental outcome after prematurity is crucial. The aim was to compare two amplitude-integrated EEG (aEEG) classifications (Hellström-Westas (HW), Burdjalov) for outcome prediction. We recruited 65 infants ≤32 weeks gestational age with aEEG recordings within the first 72 h of life and Bayley testing at 24 months corrected age or death. Statistical analyses were performed for each 24 h section to determine whether very immature/depressed or mature/developed patterns predict survival/neurological outcome and to find predictors for mental development index (MDI) and psychomotor development index (PDI) at 24 months corrected age. On day 2, deceased infants showed no cycling in 80% (HW, p = 0.0140) and 100% (Burdjalov, p = 0.0041). The Burdjalov total score significantly differed between groups on day 2 (p = 0.0284) and the adapted Burdjalov total score on day 2 (p = 0.0183) and day 3 (p = 0.0472). Cycling on day 3 (HW; p = 0.0059) and background on day 3 (HW; p = 0.0212) are independent predictors for MDI (p = 0.0016) whereas no independent predictor for PDI was found (multiple regression analyses).

CONCLUSION

Cycling in both classifications is a valuable tool to assess chance of survival. The classification by HW is also associated with long-term mental outcome. What is Known: •Neurodevelopmental outcome after preterm birth remains one of the major concerns in neonatology. •aEEG is used to measure brain activity and brain maturation in preterm infants. What is New: •The two common aEEG classifications and scoring systems described by Hellström-Westas and Burdjalov are valuable tools to predict neurodevelopmental outcome when performed within the first 72 h of life. •Both aEEG classifications are useful to predict chance of survival. The classification by Hellström-Westas can also predict long-term outcome at corrected age of 2 years.

Being Born Small for Gestational Age Influences Amplitude-Integrated Electroencephalography and Later Outcome in Preterm Infants

BACKGROUND

The impact of growth restriction on perinatal morbidity is well known, but electroencephalographic (EEG) data on its influence are still scarce.

OBJECTIVES

We aimed to analyze the influence of being born small for gestational age (SGA; defined as a birth weight <10th percentile) on the amplitude-integrated EEG (aEEG) score in the first 2 weeks of life in preterm infants born before 30 weeks of gestation, and its impact on later outcome.

METHODS

aEEG data obtained within the first 2 weeks of life on preterm infants born SGA and before 30 weeks of gestational age (GA) were analyzed retrospectively using a combined score [including background activity, occurrence of sleep-wake cycles (SWC) and suspected seizure activity]. Neurodevelopmental outcome was evaluated at 24 months by means of the Bayley Scales of Infant Development II and a standardized neurological examination.

RESULTS

One hundred and thirty-six patients were included (47 SGA and 89 controls). Infants with SGA had abnormal aEEG scores significantly more often (57 vs. 24%, p = 0.002) than infants born appropriate for gestational age (AGA). They also displayed SWC less frequently (65 vs. 96%, p = 0.001), were more likely to develop seizure activity (15 vs. 4%, p = 0.013) and had a normal neurodevelopmental outcome at the age of 2 years less frequently (36.2 vs. 59.6%, p = 0.02).

CONCLUSION

Preterm infants born SGA and before 30 weeks of GA had less optimal scores on early aEEG and a poorer neurodevelopmental outcome at 24 months than the AGA controls.