The Vulnerable Brain : neurodevelopment after neonatal critical illness

Over the last decade, the number of children admitted to specialized intensive care units has increased significantly worldwide. The majority of critically ill infants nowadays survive. This development requires our focus to broaden from minimizing mortality rates to maximizing long-term quality of life following neonatal critical illness. In this thesis we describe long-term neuropsychological outcome and the brain following treatment with neonatal extracorporeal membrane oxygenation (ECMO) and/or congenital diaphragmatic hernia (CDH). Based on our findings, we propose a common neurodevelopmental pathway across survivors of neonatal critical illness, in which early hippocampal alterations are associated with long-term memory deficits, irrespective of underlying disease or gestational age. We also report the results from a nationwide, randomized controlled trial assessing the effects of Cogmed Working Memory Training on neuropsychological outcome and the brain in neonatal ECMO and/or CDH survivors. The findings presented in this thesis demonstrate the importance of long-term neurodevelopmental follow-up in survivors of neonatal critical illness and stress the need for early risk stratification and targeted intervention strategies for these children

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

Verbal and visual-spatial memory problems at adolescent age after neonatal extracorporeal membrane oxygenation

__Objectives__ To assess neuropsychological outcome in 17- and 18-year–old neonatal extracorporeal membrane oxygenation survivors. __Design__ A prospective longitudinal follow-up study. __Setting__ Follow-up program at the Erasmus MC-Sophia Children’s Hospital in Rotterdam, The Netherlands. __Patients__ Thirty adolescents 17 or 18 years old, treated between 1991 and 1997, underwent neuropsychological assessment. __Interventions__ None. __Measurements and Main Results__ Attention, memory, executive functioning, visual-spatial functions, social-emotional functioning, and behavior were assessed with validated instruments, and data were compared with reference data. Included predictors for analysis of adverse outcome were diagnosis, age at start extracorporeal membrane oxygenation, convulsions, and use of anti-epileptics. Adolescents’ performance (expressed as mean [sd] z-score) was significantly lower than the norm on short-term and long-term verbal memory (z-score = -1.40 [1.58], p = 0.016; z-score = -1.54 [1.67], p = 0.010, respectively), visual-spatial memory (z-score = -1.65 [1.37], p = 0.008; z-score = -1.70 [1.23], p = 0.008, respectively), and working memory (32% vs 9% in the norm population). Parents reported more problems for their children regarding organization of materials (z-score = −0.60 [0.90]; p = 0.03) and behavior evaluation (z-score = −0.53 [0.88]; p = 0.05) on a questionnaire. Patients reported more withdrawn/depressed behavior (z-score = −0.47 [0.54]; p = 0.02), somatic complaints (z-score = −0.43 [0.48]; p = 0.03), and social problems (z-score = −0.41 [0.46]; p = 0.04). Patients reported more positive feelings of self-esteem and an average health status. __Conclusions__ Adolescents treated with neonatal extracorporeal membrane oxygenation are at risk of verbal, visual-spatial, and working-memory problems. Future research should focus on 1) the longitudinal outcome of specific neuropsychological skills in adolescence and adulthood; 2) identifying risk factors of neuropsychological dysfunction; 3) evaluating to what extent “severity of illness” is responsible for acquired brain injury; and 4) effects of timely cognitive rehabilitation

Memory deficits following neonatal critical illness: A common neurodevelopmental pathway

Summary Over the last decade, knowledge has emerged that children growing up after neonatal critical illness, irrespective of underlying diagnosis, are at risk of memory impairment and school problems. Strikingly, these problems are manifest even when intelligence is normal. In this review, we propose a common neurodevelopmental pathway following neonatal critical illness by demonstrating that the 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 being a consequence of underlying diagnosis, we suggest that this shared vulnerability is most likely related to common conditions associated with neonatal critical illness. These include hypoxia, neuroinflammation, stress, exposure to anaesthetics, or a complex interplay of these factors at different postconceptional ages. Future work should be aimed at improving early identification of patients at risk and evaluating intervention modalities, such as cognitive or exercise training

Neuropsychological Follow-up After Neonatal ECMO

OBJECTIVE: To assess the longitudinal development of intelligence and its relation to school abstract performance in a nationwide cohort of neonatal extracorporeal membrane oxygenation (ECMO) survivors and evaluate predictors of outcome at 8 years of age. METHODS: Repeated measurements assessed intelligence of neonatal ECMO survivors at 2, 5, and 8 years (n = 178) with the use of validated, standardized instruments. Selective attention (n = 148) and type of education were evaluated in the 8-year-olds. RESULTS: Intelligence remained stable and average across development (mean ± SD IQ: at 2 years, 102 ± 18; at 5 years, 100 ± 17; and at 8 years, 99 ± 17 [P = .15]). Children attending regular education without the need for help (n

Neonatal critical illness and development: white matter and hippocampus alterations in school-age neonatal ECMO survivors

Aim: Examine the neurobiology of long-term neuropsychological deficits following neonatal extracorporeal membrane oxygenation (ECMO). Method: This cross-sectional study assessed white matter integrity and hippocampal volume of ECMO survivors (8-15yrs) and healthy controls (8-17yrs) using Diffusion Tensor Imaging and structural MRI, respectively. Neuropsychological outcome was evaluated in patients. Included clinical predictors of white matter integrity: age start ECMO, ECMO duration, highest oxygenation index before ECMO, highest mean airway pressure and mechanical ventilation duration. Results: Patients (n=23) had lower global fractional anisotropy than controls (n=54)(patients=.368; controls=.381; p=.02), but similar global mean diffusivity (p=.41). Patients had lower fractional anisotropy in the left cingulum bundle (patients=.345; controls=.399; p<.001) and higher mean diffusivity in a region of the left parahippocampal cingulum (patients=.916; controls=.871; p<.001). Higher global mean diffusivity predicted worse verbal memory in patients (n=17)(β=-.74, p=.01). Patients (n=23) had smaller bilateral hippocampal volume than controls (n=43)(left: p< .001; right: p< .001). In patients, this was related to worse verbal memory (left: β=.65, p=.02; right: β=.71, p=.01). Interpretation: Neonatal ECMO survivors are at risk for long-term brain alterations, which may partly explain long-term neuropsychological impairments. Neuroimaging may contribute to better risk stratification of long-term impairments

Risk factors of impaired neuropsychological 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 (ECMO) and/or congenital diaphragmatic hernia (CDH). 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 ECMO and/or CDH. __Design__ Prospective follow-up study. __Setting__ Tertiary university hospital. __Patients__ Sixty-five eight-year-old survivors of neonatal ECMO and/or CDH. __Interventions__ None. __Measurements and Main Results__ Intelligence, attention, memory, executive functioning and visuospatial processing were evaluated

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 (CWM

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

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