Contributions of working memory and sustained attention to children’s reading achievement: A commonality analysis approach

Annual Research Review: Exposure to environmental chemicals and psychosocial stress and the development of children's learning difficulties

Although awareness of the role of environmental exposures in children's cognitive development is increasing, learning difficulties have not yet been a major focus of environmental health science. Learning difficulties disproportionately affect children living in economic disadvantage, yielding an 'achievement gap.' Studies examining the neurobiology of reading and math have mostly included economically advantaged youth, leaving a great deal unknown about the neural underpinnings of reading and math difficulties in youth living in disadvantaged contexts. Critically, due to environmental injustice, these youth are disproportionately exposed to environmental neurotoxicants. Herein, we review literature supporting a theoretical framework of environmentally associated phenotypes of learning difficulties. We propose that prenatal exposure to neurotoxicants and early-life exposure to psychosocial stressors increases risk for learning difficulties via effects on neural circuits that support cognitive processes which, in addition to literacy and numeracy, are integral to acquiring and performing academic skills. We describe models in which (1) prenatal exposure to air pollution has a main effect on learning via brain structure and function or associated domain-general cognitive processes and (2) a joint 'two-hit' pathway in which prenatal air pollution exposure followed by early life stress-when combined and sequential-increases risk for learning difficulties also via effects on brain structure, function, and/or associated cognitive processes. We review a select literature documenting effects of exposure to pollutants and early life stress on relevant neural circuits and associated cognitive processes in animal models and parallel findings in human epidemiologic studies. We advocate for team science in which researchers, practitioners, and policymakers collaborate to increase health literacy about environmentally associated phenotypes of learning difficulties and support the development of precision-oriented instructional and environmental intervention methods for youth living in economic disadvantage.

Attention and executive functioning in children and adolescents treated for high-risk acute lymphoblastic leukemia: A report from the Children's Oncology Group (COG)

OBJECTIVES

Survivors of childhood B-acute lymphoblastic leukemia (B-ALL) are at risk for difficulties with attention and executive functioning (EF) as a late effect of treatment. The present study aimed to identify treatment and demographic factors associated with risk for difficulties with EF in youth treated for high-risk B-ALL.

METHOD

Children and adolescents with B-ALL treated on Children's Oncology Group (COG) protocol AALL0232 were randomized to high-dose or escalating-dose methotrexate (MTX), and either dexamethasone or prednisone during the induction phase. Neuropsychological functioning was evaluated via protocol AALL06N1, including performance-based and parent-report measures, for 177 participants (57% female, 81% white; mean age at diagnosis = 8.4 years; SD = 5.0) 8-24 months following treatment completion.

RESULTS

Mean scores for all attention and EF measures were within the average range, with no significant differences as a function of MTX delivery or steroid treatment (all p > 0.05). In multivariable models, participants with US public insurance exhibited significantly greater parent-reported EF difficulties than those with US private or non-US insurance (p ≤ 0.05). Additionally, participants diagnosed under 10 years of age performed significantly more poorly on measures of attention (i.e., continuous performance task, p ≤ 0.05) and EF (i.e., verbal fluency and tower planning task, p ≤ 0.05).

CONCLUSIONS

For survivors of pediatric B-ALL, treatment-related factors were not associated with attention or EF outcomes. In contrast, outcomes varied by demographic characteristics, including age and insurance type, an indicator of economic hardship. Future research is needed to more directly assess the contribution of socioeconomic status on cognitive outcomes in survivors.

Cognition and Cognitive Reserve

Cognition is a mental process that provides the ability to think, know, and learn. Though cognitive skills are necessary to do daily tasks and activities, cognitive aging causes changes in various cognitive functions. Cognitive abilities that are preserved and strengthened by experience can be kept as a reserve and utilized when necessary. The concept of reserving cognition was found when people with Alzheimer's disease had differences in clinical manifestations and cognitive functions. The cognitive reserve builds resilience against cognitive decline and improves the quality of life. Also, several lines of studies have found that the plasticity between neurons has a significant impact on cognitive reserve and acts against cognitive decline. To extend the findings, the present study provides a comprehensive understanding of cognitive reserve and the variables that are involved in maintaining cognition. The study also considers reading as one of the cognitive proxies that develops and maintains cognitive reserve.

Working memory development: A 50-year assessment of research and underlying theories

The author has thought about working memory, not always by that name, since 1969 and has conducted research on its infant and child development since the same year that the seminal work of Baddeley and Hitch (1974) was published. The present article assesses how the field of working memory development has been influenced since those years by major theoretical perspectives: empiricism (along with behaviorism), nativism (along with modularity), cognitivism (along with constructivism), and dynamic systems theory. The field has not fully discussed the point that these theoretical perspectives have helped to shape different kinds of proposed working memory systems, which in turn have deeply influenced what is researched and how it is researched. Here I discuss that mapping of theoretical viewpoints onto assumptions about working memory and trace the influence of this mapping on the field of working memory development. I illustrate where these influences have led in my own developmental research program over the years.

The intellectual profile of pediatric patients with posterior cortex epilepsy

BACKGROUND

Cognitive functioning in epileptic syndromes has been widely explored in patients with temporal lobe epilepsy (TLE), but few studies have investigated the neuropsychological profile in posterior cortex epilepsy (PCE). In this study, we investigated the presurgical intellectual profile of children and adolescents with drug-resistant PCE.

METHODS

Children and adolescents diagnosed with PCE (n = 25) participated in this study. The data were obtained from medical records, with assessments carried out between the years 2003 and 2019. To compare the intellectual profile, we also included patients diagnosed with frontal (n = 26) and temporal lobe epilepsy (n = 40). The Wechsler Intelligence Scales were used for the assessment of general intelligence.

RESULTS

There was an effect of the brain region on the Working Memory Index (p < 0.01), in which patients with TLE had significantly higher scores than groups with FLE (p < 0.01) and PCE (p < 0.05). We also demonstrated that patients with PCE tended to perform worse in the Processing Speed Index than patients with TLE (p = 0.055). The Full-Scale Intelligence Quotient, Verbal Comprehension, and Perceptual Reasoning indexes did not differ among the brain regions.

CONCLUSIONS

Children and adolescents with PCE demonstrated significant impairment in working memory and processing speed. The pattern of cognitive dysfunction in PCE was similar to that observed in FLE, which expands the evidence of the involvement of frontoparietal networks on cognitive proficiency.