Neurobiologic Correlates of Attention and Memory Deficits Following Critical Illness in Early Life

Microstructural properties of attention-related white matter tracts are associated with the renewal effect of extinction

The tendency to show the renewal effect of extinction appears as an intra-individually stable, reproducible processing strategy associated with differential patterns of BOLD activation in hippocampus, iFG and vmPFC, as well as differential resting-state functional connectivity between prefrontal regions and the dorsal attention network. Also, pharmacological modulations of the noradrenergic system that influence attentional processing have partially different effects upon individuals with (REN) and without (NoREN) a propensity for renewal. However, it is as yet unknown whether REN and NoREN individuals differ regarding microstructural properties in attention-related white matter (WM) regions, and whether such differences are related to noradrenergic processing. In this diffusion tensor imaging (DTI) analysis we investigated the relation between microstructural properties of attention-related WM tracts and ABA renewal propensity, under conditions of noradrenergic stimulation by means of the noradrenergic reuptake inhibitor atomoxetine, compared to placebo. Fractional anisotropy (FA) was higher in participants with noradrenergic stimulation (ATO) compared to placebo (PLAC), the effect was predominantly left-lateralized and based on the comparison of ATO REN and PLAC REN participants. In REN participants of both treatment groups, FA in several WM tracts showed a positive correlation with the ABA renewal level, suggesting higher renewal levels were associated with higher microstructural integrity. These findings point towards a relation between microstructural properties of attention-related WM tracts and the propensity for renewal that is not specifically dependent on noradrenergic processing.

Long-Term Neurobehavioral and Functional Outcomes of Pediatric Extracorporeal Membrane Oxygenation Survivors

There are limited reports of neurobehavioral outcomes of children supported on extracorporeal membrane oxygenation (ECMO). This observational study aims to characterize the long-term (≥1 year) neurobehavioral outcomes, identify risk factors associated with neurobehavioral impairment, and evaluate the trajectory of functional status in pediatric ECMO survivors. Pediatric ECMO survivors ≥1-year postdecannulation and ≥3 years of age at follow-up were prospectively enrolled and completed assessments of adaptive behavior (Vineland Adaptive Behavior Scales, Third Edition [Vineland-3]) and functional status (Functional Status Scale [FSS]). Patient characteristics were retrospectively collected. Forty-one ECMO survivors cannulated at 0.0-19.8 years (median: 2.4 [IQR: 0.0, 13.1]) were enrolled at 1.3-12.8 years (median: 5.5 [IQR: 3.3, 6.5]) postdecannulation. ECMO survivors scored significantly lower than the normative population in the Vineland-3 Adaptive Behavior Composite (85 [IQR: 70, 99], P < 0.001) and all domains (Communication, Daily Living, Socialization, Motor). Independent risk factors for lower Vineland-3 composite scores included extracorporeal cardiopulmonary resuscitation, electrographic seizures during ECMO, congenital heart disease, and premorbid developmental delay. Of the 21 patients with impaired function at discharge (FSS ≥8), 86% reported an improved FSS at follow-up. Pediatric ECMO survivors have, on average, mild neurobehavioral impairment related to adaptive functioning years after decannulation. Continued functional recovery after hospital discharge is likely.

Long-term follow-up of patients with congenital diaphragmatic hernia

Neonates with congenital diaphragmatic hernia encounter a number of surgical and medical morbidities that persist into adulthood. As mortality improves for this population, these survivors warrant specialized follow-up for their unique disease-specific morbidities. Multidisciplinary congenital diaphragmatic hernia clinics are best positioned to address these complex long-term morbidities, provide long-term research outcomes, and help inform standardization of best practices in this cohort of patients. This review outlines long-term morbidities experienced by congenital diaphragmatic hernia survivors that can be addressed in a comprehensive follow-up clinic.

Long-term follow-up of neuropsychological complications in neonates undergoing extracorporeal membrane oxygenation: a systematic review and meta-analysis

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been widely used in severe neonatal diseases for approximately 50 years, while few studies have concentrated on the long-term follow-up of its neuropsychological development.

OBJECTIVE

To assess the long-term neuropsychological complications in children who underwent ECMO in infancy.

METHODS

The PubMed, Web of Science, Cochrane, and EMBASE databases were searched for retrieving studies published in the recent 10 years (until June 10, 2022). All studies were eligible that concentrated on the long-term follow-up of neuropsychological complications in neonates undergoing ECMO. Excluding animal studies, neonates with congenital craniocerebral dysplasia and studies with data from the same center performed at different times. Statistical analysis was performed using RevMan 5.3 and Stata/SE 12.0 software. A random-effects model was used to report results. The sensitivity analysis was utilized to identify sources of heterogeneity.

RESULTS

The meta-analysis of 10 studies that enrolled 1199 patients was conducted, showing the pooled morbidity of intelligence (pooled morbidity: 20.3%, 95% CI: 0.16-0.25, I2: 9.5%, P=0.33), motor activity (pooled morbidity: 10.3%, 95%CI: 0.07-0.14, I2: 43.5%, P=0.15), learning (pooled morbidity: 9.0%, 95%CI: -0.03-0.21, I2: 63.2%, P=0.10), hearing (pooled morbidity: 15.7%, 95%CI: 0.02-0.29, I2: 94.2%, P=0.00), vision (pooled morbidity: 18.5%, 95%CI: 0.12-0.25, I2: 0%, P=0.46), cognition (pooled morbidity: 26.3%, 95%CI: 0.19-0.34, I2: 0%, P=0.32), attention (pooled morbidity: 7.4%, 95%CI: 0.02-0.13, I2: 38.9%, P=0.20), speed in attention (pooled morbidity: 69.9%, 95%CI: 0.62-0.78), and accuracy in attention (pooled morbidity: 39.0%, 95%CI: 0.30-0.48) in neonates undergoing ECMO. The results of the Begg's test and sensitivity analysis indicated that the heterogeneity was originated from factors other than sample size.

CONCLUSION

This systematic review and meta-analysis showed that neonates undergoing ECMO were associated with various neuropsychological complications. Additional randomized controlled trials (RCTs) with a larger sample size and a higher quality are needed.

Neurocognitive functioning and health-related quality of life of children after pediatric intensive care admission: a systematic review

OBJECTIVE

This study systematically reviewed recent findings on neurocognitive functioning and health-related quality of life (HRQoL) of children after pediatric intensive care unit admission (PICU).

DATA SOURCES

Electronic databases searched included Embase, Medline Ovid, Web of Science, Cochrane CENTRAL, and Google Scholar. The search was limited to studies published in the last five years (2015-2019).

STUDY SELECTION

Original studies assessing neurocognitive functioning or HRQoL in children who were previously admitted to the PICU were included in this systematic review.

DATA EXTRACTION

Of the 3649 identified studies, 299 met the inclusion criteria based on title abstract screening. After full-text screening, 75 articles were included in the qualitative data reviewing: 38 on neurocognitive functioning, 33 on HRQoL, and 4 on both outcomes.

DATA SYNTHESIS

Studies examining neurocognitive functioning found overall worse scores for general intellectual functioning, attention, processing speed, memory, and executive functioning. Studies investigating HRQoL found overall worse scores for both physical and psychosocial HRQoL. On the short term (≤ 12 months), most studies reported HRQoL impairments, whereas in some long-term studies HRQoL normalized. The effectiveness of the few intervention studies during and after PICU admission on long-term outcomes varied.

CONCLUSIONS

PICU survivors have lower scores for neurocognitive functioning and HRQoL than children from the general population. A structured follow-up program after a PICU admission is needed to identify those children and parents who are at risk. However, more research is needed into testing interventions in randomized controlled trials aiming on preventing or improving impairments in critically ill children during and after PICU admission.

Congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a rare birth defect characterized by incomplete closure of the diaphragm and herniation of fetal abdominal organs into the chest that results in pulmonary hypoplasia, postnatal pulmonary hypertension owing to vascular remodelling and cardiac dysfunction. The high mortality and morbidity rates associated with CDH are directly related to the severity of cardiopulmonary pathophysiology. Although the aetiology remains unknown, CDH has a polygenic origin in approximately one-third of cases. CDH is typically diagnosed with antenatal ultrasonography, which also aids in risk stratification, alongside fetal MRI and echocardiography. At specialized centres, prenatal management includes fetal endoscopic tracheal occlusion, which is a surgical intervention aimed at promoting lung growth in utero. Postnatal management focuses on cardiopulmonary stabilization and, in severe cases, can involve extracorporeal life support. Clinical practice guidelines continue to evolve owing to the rapidly changing landscape of therapeutic options, which include pulmonary hypertension management, ventilation strategies and surgical approaches. Survivors often have long-term, multisystem morbidities, including pulmonary dysfunction, gastroesophageal reflux, musculoskeletal deformities and neurodevelopmental impairment. Emerging research focuses on small RNA species as biomarkers of severity and regenerative medicine approaches to improve fetal lung development.

Extracorporeal Life Support Organization (ELSO) Guidelines for Follow-up After Neonatal and Pediatric Extracorporeal Membrane Oxygenation

Neonates and children who have survived critical illness severe enough to require extracorporeal membrane oxygenation (ECMO) are at risk for neurologic insults, neurodevelopmental delays, worsening of underlying medical conditions, and development of new medical comorbidities. Structured neurodevelopmental follow-up is recommended for early identification and prompt interventions of any neurodevelopmental delays. Even children who initially survive this critical illness without new medical or neurologic deficits remain at risk of developing new morbidities/delays at least through adolescence, highlighting the importance of structured follow-up by personnel knowledgeable in the sequelae of critical illness and ECMO. Structured follow-up should be multifaceted, beginning predischarge and continuing as a coordinated effort after discharge through adolescence. Predischarge efforts should consist of medical and neurologic evaluations, family education, and co-ordination of long-term ECMO care. After discharge, programs should recommend a compilation of pediatric care, disease-specific care for underlying or acquired conditions, structured ECMO/neurodevelopmental care including school performance, parental education, and support. Institutionally, regionally, and internationally available resources will impact the design of individual center's follow-up program. Additionally, neurodevelopmental testing will need to be culturally and lingually appropriate for centers' populations. Thus, ECMO centers should adapt follow-up program to their specific populations and resources with the predischarge and postdischarge components described here.

Towards integrative neuromonitoring of the surgical newborn: A systematic review

BACKGROUND

The altered neurodevelopment of children operated on during the neonatal period might be due to peri-operative changes in the homeostasis of brain perfusion. Monitoring of vital signs is a standard of care, but it does not usually include monitoring of the brain.

OBJECTIVES

To evaluate methods of monitoring the brain that might be of value. We also wanted to clarify if there are specific risk factors that result in peri-operative changes and how this might be evaluated.

DESIGN

Systematic review.

DATA SOURCES

A structured literature search was performed in MEDLINE in Ovid, Embase, Cochrane CENTRAL, Web of Science and Google Scholar.

ELIGIBILITY CRITERIA

Studies in neonates who received peri-operative neuromonitoring were eligible for inclusion; studies on neurosurgical procedures or cardiac surgery with cardiopulmonary bypass and/or deep hypothermia cardiac arrest were excluded.

RESULTS

Nineteen of the 24 included studies, totalling 374 infants, reported the use of near-infrared spectroscopy. Baseline values of cerebral oxygenation greatly varied (mean 53 to 91%) and consequently, no coherent results were found. Two studies found a correlation between cerebral oxygenation and mean arterial blood pressure. Five studies, with in total 388 infants, used (amplitude-integrated) electro-encephalography to study peri-operative brain activity. Overall, the brain activity decreased during anaesthesia and epileptic activity was more frequent in the peri-operative phase. The association between intra-operative cerebral saturation or activity and neuro-imaging abnormalities and/or neurodevelopmental outcome was investigated in six studies, but no association was found.

CONCLUSION

Neuromonitoring with the techniques currently used will neither help our understanding of the altered neonatal pathophysiology, nor enable early detection of deviation from the norm. The modalities lack specificity and are not related to clinical (long-term) outcome or prognosis. Accordingly, we were unable to draw up a monitoring guideline.

Long term follow-up in congenital diaphragmatic hernia

Survivorship of patients with congenital diaphragmatic hernia (CDH) has created a unique cohort of children, adolescents and adults with complex medical and surgical needs. Morbidities specific to this disease benefit from multi-specialty care, and the long term follow up of these patients offers a tremendous opportunity for research and collaboration. Herein we aim to offer an overview of the challenges that modern CDH survivors face, and include a risk-stratified algorithm as a general guideline for a multi-specialty follow up program.

Analgesics and Sedatives in Critically Ill Newborns and Infants: The Impact on Long-Term Neurodevelopment

Inadequate pain and/or stress management in preterm- and term-born infants has been associated with increased morbidity and even mortality. However, exposure to analgosedatives during early infancy may also be one of the risk factors for subsequent neurodevelopmental impairment, at least in animal studies. Because infants admitted to neonatal or pediatric intensive care units may receive high amounts of these drugs for prolonged periods of time and the majority of these infants nowadays survive to discharge, this is of major concern. A balanced approach that incorporates the assessment and quantification of both wanted effects as well as unwanted side effects is therefore needed. In this article, the optimal dose determination of commonly used analgosedative drugs as well as their potential long-term effects on the developing human brain and neuropsychological functioning are reviewed.

Working Memory Training Following Neonatal Critical Illness: A Randomized Controlled Trial

OBJECTIVES

To test the immediate and long-term effectiveness of Cogmed Working Memory Training following extracorporeal membrane oxygenation and/or congenital diaphragmatic hernia.

DESIGN

A nationwide randomized controlled trial assessing neuropsychologic outcome immediately and 1 year post Cogmed Working Memory Training, conducted between October 2014 and June 2017. Researchers involved in the follow-up assessments were blinded to group allocation.

SETTING

Erasmus MC-Sophia Children's Hospital, Rotterdam, and Radboud University Medical Center, Nijmegen, the Netherlands.

PATIENTS

Eligible participants were neonatal extracorporeal membrane oxygenation and/or congenital diaphragmatic hernia survivors (8-12 yr) with an intelligence quotient greater than or equal to 80 and a z score less than or equal to -1.5 on at least one (working) memory test at first assessment.

INTERVENTIONS

Cogmed Working Memory Training, comprising 25 45-minute training sessions for 5 consecutive weeks at home.

MEASUREMENTS AND MAIN RESULTS

Participants were randomized to Cogmed Working Memory Training (n = 19) or no intervention (n = 24) (two dropped out after T0). Verbal working memory (estimated coefficient = 0.87; p = 0.002) and visuospatial working memory (estimated coefficient=0.96, p = 0.003) significantly improved at T1 post Cogmed Working Memory Training but was similar between groups at T2 (verbal, p = 0.902; visuospatial, p = 0.416). Improvements were found at T2 on long-term visuospatial memory following Cogmed Working Memory Training (estimated coefficient = 0.95; p = 0.003). Greater improvements in this domain at T2 following Cogmed Working Memory Training were associated with better self-rated school functioning (r = 0.541; p = 0.031) and parent-rated attention (r = 0.672; p = 0.006).

CONCLUSIONS

Working memory improvements after Cogmed Working Memory Training disappeared 1 year post training in neonatal extracorporeal membrane oxygenation and/or congenital diaphragmatic hernia survivors. Gains in visuospatial memory persisted 1 year post intervention. Cogmed Working Memory Training may be beneficial for survivors with visuospatial memory deficits.

Risk Factors of Impaired Neuropsychologic Outcome in School-Aged Survivors of Neonatal Critical Illness

OBJECTIVE

Until now, long-term outcome studies have focused on general cognitive functioning and its risk factors following neonatal extracorporeal membrane oxygenation and/or congenital diaphragmatic hernia. However, it is currently unknown which neuropsychological domains are most affected in these patients and which clinical variables can be used to predict specific neuropsychological problems. This study aimed to identify affected neuropsychological domains and its clinical determinants in survivors of neonatal extracorporeal membrane oxygenation and/or congenital diaphragmatic hernia.

DESIGN

Prospective follow-up study.

SETTING

Tertiary university hospital.

PATIENTS

Sixty-five 8-year-old survivors of neonatal extracorporeal membrane oxygenation and/or congenital diaphragmatic hernia.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Intelligence, attention, memory, executive functioning and visuospatial processing were evaluated using validated tests and compared with Dutch reference data. Assessed risk factors of outcome were illness severity indicators, number of anesthetic procedures in the first year of life, and growth at 1 year. Patients had average intelligence (mean intelligence quotient ± SD, 95 ± 16), but significantly poorer sustained attention (mean z score ± SD, -2.73 ± 2.57), verbal (immediate, -1.09 ± 1.27; delayed, -1.14 ± 1.86), and visuospatial memory (immediate, -1.48 ± 1.02; delayed, -1.57 ± 1.01; recognition, -1.07 ± 3.10) than the norm. Extracorporeal membrane oxygenation-treated congenital diaphragmatic hernia patients had significantly lower mean intelligence quotient (84 ± 12) than other neonatal extracorporeal membrane oxygenation patients (94 ± 10) and congenital diaphragmatic hernia patients not treated with extracorporeal membrane oxygenation (100 ± 20). Maximum vasoactive-inotropic score was negatively associated with delayed verbal (B = -0.02; 95% CI, -0.03 to -0.002; p = 0.026) and visuospatial memory (B = -0.01; 95% CI, -0.02 to -0.001; p = 0.024).

CONCLUSIONS

We found memory and attention deficits in 8-year-old neonatal extracorporeal membrane oxygenation and congenital diaphragmatic hernia survivors. The maximum dose of vasoactive medication was negatively associated with verbal and visuospatial memory, which may suggest an effect of early cerebral hypoperfusion in determining these abnormalities.

Training-induced white matter microstructure changes in survivors of neonatal critical illness: A randomized controlled trial

In a nationwide randomized controlled trial, white matter microstructure was assessed before and immediately after Cogmed Working-Memory Training (CWMT) in school-age neonatal critical illness survivors. Eligible participants were survivors (8-12 years) with an IQ ≥ 80 and a z-score of ≤ -1.5 on (working)memory test at first assessment. Diffusion Tensor Imaging was used to assess white matter microstructure. Associations between any training-induced changes and improved neuropsychological outcome immediately and one year post-CWMT were evaluated as well. The trial was conducted between October 2014-June 2017 at Erasmus MC-Sophia, Rotterdam, Netherlands. Researchers involved were blinded to group allocation. Participants were randomized to CWMT(n = 14) or no-intervention(n = 20). All children completed the CWMT. Global fractional anisotropy(FA) increased significantly post-CWMT compared to no-intervention(estimated-coefficient = .007, p = .015). Increased FA(estimated coefficient = .009, p = .033) and decreased mean diffusivity(estimated-coefficient = -.010, p = .018) were found in the left superior longitudinal fasciculus(SFL) post-CWMT compared no-intervention. Children after CWMT who improved with >1SD on verbal working-memory had significantly higher FA in the left SLF post-CWMT(n = 6; improvement = .408 ± .01) than children without this improvement post-CWMT(n = 6; no-improvement = .384 ± .02), F(1,12) = 6.22, p = .041, ηp2 = .47. No other structure-function relationships were found post-CWMT. Our findings demonstrate that white matter microstructure and associated cognitive outcomes are malleable by CWMT in survivors of neonatal critical illness.

Neurocognitive Outcome After Treatment With(out) ECMO for Neonatal Critical Respiratory or Cardiac Failure

Over the years, it has become clear that children growing up after neonatal critical illness are at high risk of long-term neurocognitive deficits that impact their school performance and daily life activities. Although the pathophysiological mechanisms remain largely unknown, emerging evidence seems to suggest that long-term neuropsychological deficits following neonatal critical illness are not associated with the type of treatment, such as extracorporeal membrane oxygenation (ECMO), but rather with underlying disease processes. In this review, neurocognitive outcome and brain pathology following neonatal critical respiratory and cardiac illness, either treated with or without ECMO, are described and compared in order to gain insight into potential underlying pathophysiological mechanisms. Putting these findings together, it becomes apparent that both children with complex congenital heart disease and children who survived severe respiratory failure are at risk of neurocognitive deficits later in life. Neurorehabilitation strategies, such as Cogmed working-memory training, are discussed. While prevention of neurocognitive deficits altogether should be strived for in the future, this is not realistic at this moment. It is therefore of great importance that children growing up after neonatal critical illness receive long-term care that includes psychoeducation and personalized practical tools that can be used to improve their daily life activities.

Memory deficits following neonatal critical illness: a common neurodevelopmental pathway

Over the past decade, evidence has emerged that children growing up after neonatal critical illness, irrespective of underlying diagnosis, are at risk of memory impairment and academic problems. These difficulties are manifest even when intelligence is within the normal range. In this Review, we propose a common neurodevelopmental pathway following neonatal critical illness by showing that survivors of preterm birth, congenital heart disease, and severe respiratory failure share an increased risk of long-term memory deficits and associated hippocampal alterations. Rather than a consequence of underlying diagnosis, we suggest that this shared vulnerability is probably related to common conditions associated with neonatal critical illness, including hypoxia, neuroinflammation, stress, exposure to anaesthetics, or a complex interplay of these factors at different postconceptional ages. Future work should be aimed at improvement of early identification of patients at risk and evaluation of intervention modalities, such as exercise or cognitive training.

Improving Long-Term Outcomes After Extracorporeal Membrane Oxygenation: From Observational Follow-Up Programs Toward Risk Stratification

Since the introduction of extracorporeal membrane oxygenation (ECMO), more neonates and children with cardiorespiratory failure survive. Interest has therefore shifted from reduction of mortality toward evaluation of long-term outcomes and prevention of morbidity. This review addresses the changes in ECMO population and the ECMO-treatment that may affect long-term outcomes, the diagnostic modalities to evaluate neurological morbidities and their contributions to prognostication of long-term outcomes. Most follow-up data have only become available from observational follow-up programs in neonatal ECMO-survivors. The main topics are discussed in this review. Recommendations for long-term follow up depend on the presence of neurological comorbidity, the nature and extent of the underlying disease, and the indication for ECMO. Follow up should preferably be offered as standard of care, and in an interdisciplinary, structured and standardized way. This permits evaluation of outcome data and effect of interventions. We propose a standardized approach and recommend that multiple domains should be evaluated during long-term follow up of neonates and children who needed extracorporeal life support.