Electroencephalographic functional connectivity in extreme prematurity: a pilot study based on graph theory

Prospective assessment of early developmental markers and their association with neuropsychological impairment

Children who experience adversities in the pre-perinatal period are at increased risk of developing impairment later in life, despite the absence of overt brain and neurological abnormalities. However, many of these children exhibit sequelae several years after a period of normal appearance. As a result, the need for reliable developmental assessments for the early detection of infants at high risk of adverse neurodevelopmental outcomes has emerged. The Griffiths Mental Developmental Scales have a promising but poorly explored prognostic ability. This longitudinal study evaluated the predictive power of the Griffiths Mental Developmental Scales at 12 and 24 months on the cognitive and neuropsychological profile at 6 years of age in a sample of 70 children with a history of prematurity or perinatal asphyxia but without brain and neurological abnormalities. We found that the Griffiths Mental Developmental Scales at 24 months had good predictive ability on the intelligence quotient at 6 years and the capacity to predict some neuropsychological performances. On the other hand, the Griffiths Mental Developmental Scale at 12 months was not associated with the performance at 6 years or 24 months.   Conclusion: Data on brain development converge to indicate that the first two years of age represent a critical stage of development, particularly for children experiencing mild pre-perinatal adversities who are thought to exhibit white matter dysmaturity. For this reason, this age is crucial for identifying which children are at major risk, leaving enough time to intervene before overt deficits become apparent. Brain development in the first 2 years could explain the limited reliability of early neurodevelopmental testing. What is Known: • Pre-perinatal adversities increase the risk of developing neurodevelopmental disorders. • The predictive ability of the Griffith scale is poorly explored in low-grade conditions. What is New: • The predictive ability of the Griffith scale has been investigated in low-risk children. • A complete neuropsychological profile could offer a more accurate prediction than the intellectual quotient.

Mood and anxiety spectrum disorders detected by neuropsychiatric interviews in young adults born preterm: A prospective cohort study

BACKGROUND

Psychopathology has not yet been studied beyond pediatric age for all degrees of prematurity, including late-preterm, particularly in those who grew up with no apparent neurodevelopmental sequelae. This study aimed to examine psychopathological outcome following preterm birth and admission to neonatal intensive care in young adults without major neurodevelopmental and psychopathological problems that emerged during childhood.

METHODS

An Italian single-center prospective cohort study. Eighty-nine young adults (40 admitted to neonatal intensive care unit with less than 37 weeks of gestation and no medical history of other neurological or psychiatric conditions in childhood and 49 healthy peers born at term, matched by age, sex, and education) underwent neuropsychiatric interviews at the age of 20 ± 1 years; MINI International Neuropsychiatric Interview, Beck Depression Inventory and Barratt Impulsive Scale, results were correlated to individual neonatal data and cognitive measures.

RESULTS

We found a significantly higher prevalence of psychopathology at MINI score (22.5% vs. 4.2%; χ2 = 6.7; p = 0,010) and prevalence of previous stressful life events in the preterm compared to at-term group. B.D.I. (testing depression) and BIS-11(testing impulsivity) did not highlight a statistically significant difference between the groups. All patients had average I.Q., a statistically significant difference (p < 0.001) was observed between groups with a better performance in controls than cases.

CONCLUSIONS

Preterm infants attaining young adult age with otherwise typical development during childhood are at risk of psychopathology and lower resilience to stressful life events. The MINI interview could be a useful tool to highlight the psychopathology of preterm infants attaining adult age.

Grounding Adaptive Cognitive Control in the Intrinsic, Functional Brain Organization: An HD-EEG Resting State Investigation

In a recent study, we used the dynamic temporal prediction (DTP) task to demonstrate that the capability to implicitly adapt motor control as a function of task demand is grounded in at least three dissociable neurofunctional mechanisms: expectancy implementation, expectancy violation and response implementation, which are supported by as many distinct cortical networks. In this study, we further investigated if this ability can be predicted by the individual brain's functional organization at rest. To this purpose, we recorded resting-state, high-density electroencephalography (HD-EEG) in healthy volunteers before performing the DTP task. This allowed us to obtain source-reconstructed cortical activity and compute whole-brain resting state functional connectivity at the source level. We then extracted phase locking values from the parceled cortex based on the Destrieux atlas to estimate individual functional connectivity at rest in the three task-related networks. Furthermore, we applied a machine-learning approach (i.e., support vector regression) and were able to predict both behavioral (response speed and accuracy adaptation) and neural (ERP modulation) task-dependent outcome. Finally, by exploiting graph theory nodal measures (i.e., degree, strength, local efficiency and clustering coefficient), we characterized the contribution of each node to the task-related neural and behavioral effects. These results show that the brain's intrinsic functional organization can be potentially used as a predictor of the system capability to adjust motor control in a flexible and implicit way. Additionally, our findings support the theoretical framework in which cognitive control is conceived as an emergent property rooted in bottom-up associative learning processes.

Structural and functional brain asymmetries in the early phases of life: a scoping review

Asymmetry characterizes the brain in both structure and function. Anatomical asymmetries explain only a fraction of functional variability in lateralization, with structural and functional asymmetries developing at different periods of life and in different ways. In this work, we perform a scoping review of the cerebral asymmetries in the first brain development phases. We included all English-written studies providing direct evidence of hemispheric asymmetries in full-term neonates, foetuses, and premature infants, both at term post-conception and before. The final analysis included 57 studies. The reviewed literature shows large variability in the used techniques and methodological procedures. Most structural studies investigated the temporal lobe, showing a temporal planum more pronounced on the left than on the right (although not all data agree), a morphological asymmetry already present from the 29th week of gestation. Other brain structures have been poorly investigated, and the results are even more discordant. Unlike data on structural asymmetries, functional data agree with each other, identifying a leftward dominance for speech stimuli and an overall dominance of the right hemisphere in all other functional conditions. This generalized dominance of the right hemisphere for all conditions (except linguistic stimuli) is in line with theories stating that the right hemisphere develops earlier and that its development is less subject to external influences because it sustains functions necessary to survive.

Neonatal spectral EEG is prognostic of cognitive abilities at school age in premature infants without overt brain damage

Prematurity is a prototype of biological risk that could affect the late neurocognitive outcome; however, the condition itself remains a non-specific marker. This longitudinal 6-year study aimed to evaluate the prognostic role of neonatal spectral EEG in premature infants without neurological complications. The study cohort was 26 children born 23-34 gestational ages; all neonates underwent multichannel EEG recordings at 35 weeks post-conception. EEG data were transformed into the frequency domain and divided into delta (0.5-4 Hz), theta (5-7 Hz), alpha (8-13 Hz), and beta (14-20 Hz) frequency bands. At 6 years, a neuropsychological and behavioral evaluation was performed. Correlations between spectral bands and neuropsychological assessments were performed with a conservative and robust Bayesian correlation model using weakly informative priors. The correlation of neuropsychological tasks to spectral frequency bands highlighted a significant association with visual and auditory attention tests. The performance on the same tests appears to be mainly impaired.Conclusions: We found that spectral EEG frequencies are independent predictors of performance in attention tasks. We hypothesized that spectral EEG might reflect early circuitries' imbalance in the reticular ascending system and cumulative effect on ongoing development, pointing to the importance of early prognostic instruments. What is Known: • Prematurity is a non-specific marker of late neurocognitive risk. • Precise prognostic instruments are lacking, mostly in patients with low-grade conditions. What is New: • Longitudinal long-term studies are scarce but crucial for the inferential attributive process. • Spectral EEG frequencies are independent predictors of performance in attention tasks.

Graph theory in paediatric epilepsy: A systematic review

Graph theoretical studies have been designed to investigate network topologies during life. Network science and graph theory methods may contribute to a better understanding of brain function, both normal and abnormal, throughout developmental stages. The degree to which childhood epilepsies exert a significant effect on brain network organisation and cognition remains unclear. The hypothesis suggests that the formation of abnormal networks associated with epileptogenesis early in life causes a disruption in normal brain network development and cognition, reflecting abnormalities in later life. Neurological diseases with onset during critical stages of brain maturation, including childhood epilepsy, may threaten this orderly neurodevelopmental process. According to the hypothesis that the formation of abnormal networks associated with epileptogenesis in early life causes a disruption in normal brain network development, it is then mandatory to perform a proper examination of children with new-onset epilepsy early in the disease course and a deep study of their brain network organisation over time. In regards, graph theoretical analysis could add more information. In order to facilitate further development of graph theory in childhood, we performed a systematic review to describe its application in functional dynamic connectivity using electroencephalographic (EEG) analysis, focussing on paediatric epilepsy.