Child development researchers are asking whether the pandemic is shaping brains and behavior.
Dumitriu and her team at NewYork–Presbyterian Morgan Stanley Children's Hospital in New York City had more than two years of data on infants' development – since late 2017, they analyzed communication skills and movement of infants under six months old. Dumitriu thought it would be interesting to compare results from children born before and during the pandemic. She asked her colleague Morgan Firestein, a postdoctoral researcher at Columbia University in New York City, to assess whether there were neurodevelopmental differences between the two groups.
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Children born during the pandemic scored lower on average on tests of gross motor, fine motor and communication skills than children born before (both groups were rated by their parents). price using the established questionnaire). It doesn't matter whether their biological parents were infected with the virus or not, there seems to be something about the environment of the pandemic itself.
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Although children have generally been healthy when infected with SARS-CoV-2, preliminary research suggests that pandemic-related stress during pregnancy may negatively affect fetal brain development in some children. Furthermore, disadvantaged parents and caregivers may interact differently or less with their young children in ways that can affect the children's physical and mental abilities.
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Some children born in the past two years may have developmental delays, while others may thrive, if caregivers stay home for long periods of time and there are more opportunities for siblings to interact. As with many aspects of health during the pandemic, economic and social disparities play a clear role in who is most affected. Early data shows that mask use does not negatively affect children's emotional development. But prenatal stress may contribute to some changes in brain connectivity. The picture is evolving and many studies have not yet been peer-reviewed.
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Some researchers suggest that many children with developmental delays will be able to catch up without lasting effects. “I didn't expect that we would find that there was a generation that had been traumatized by the pandemic,” said Moriah Thomason, a child and adolescent psychologist at New York University Grossman School of Medicine.
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A SIGNIFICANT DECREASE
One lab that has managed to stay open during the COVID-19 pandemic is Brown University's Advanced Pediatric Imaging Laboratory in Providence, Rhode Island. In it, Sean Deoni, a medical biophysicist, and his colleagues use magnetic resonance imaging (MRI) and other techniques to study how environmental factors shape brain development in infants.
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Although the pandemic has changed the way they conduct research — fewer visitors and more cleaning — they continue to invite infants to their lab, to monitor motor skills, vision and language as part of a seven-year National Institutes of Health study of childhood development and later health effects.
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However, as the pandemic progressed, Deoni began hearing disturbing comments from her colleagues. “What our staff started telling me was that these kids were taking longer to pass the assessments,” Deoni recalls.
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He asked his researchers to plot and compare yearly averages and differences from the infants' neurodevelopmental scores. That's when they discovered that scores during the pandemic were much worse than in previous years. “Things just started falling late last year and early this year,” he said at the end of 2021. When they compared the results among participants, children born during the pandemic scored nearly two standard deviations lower than previously born children based on a set of tests that measure development in a similar way to IQ tests. They also found that infants from low-income families were most affected, boys were affected more than girls, and gross motor skills were most affected.
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At first, Deoni thought selection bias was at play: perhaps the families who tried to come in for testing during the pandemic were those whose children were at risk for developmental problems or had their manifestation. But over time, he became more convinced that selection bias did not explain the study results, because the children who arrived did not have different backgrounds, birth outcomes or socioeconomic statuses than those who did not. previous participants.
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These effects seem strong, but some researchers say they are not necessarily predictive of long-term problems. “IQ, as a child, is not very predictive,” says Marion van den Heuvel, a developmental neuropsychologist at Tilburg University in the Netherlands. It's really difficult to say anything about what that will mean for their future.” She points to a study showing that Romanian girls who started life in orphanages but were then adopted by foster families before age 2.5 were less likely to have mental problems at age 4. 5 years older than girls still receiving care at the facility. That situation is different from the pandemic, but shows that babies can make up for it when restrictions are lifted.
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However, Deoni found that the longer the pandemic lasted, the more deprivation problems children accumulated. When Deoni first posted his results, there was a flurry of worrying media coverage – and backlash from the research community. “There is a real concern about the fact that these results were released without peer review,” Griffin said.
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But, assuming the findings are valid, why might children born during the COVID-19 pandemic have significant cognitive, and especially motor, deficits? Deoni suspects that the problems stem from a lack of human interaction. In unpublished follow-up research, he and his team recorded parent-child interactions at home, finding that the number of words parents said to their children, and vice versa, in The past two years have been lower than previous years. He also suspects that infants and toddlers aren't getting as much gross motor practice as they should because they don't regularly play with other children or go to the playground. “And the unfortunate thing is those skills are the foundation for all the other skills,” he said.
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Other recent studies support the idea that a lack of peer interactions may hold some children back. In a study published earlier this year, researchers in the United Kingdom surveyed 189 parents of children between the ages of 8 months and 3 years, asking whether their children attended daycare or preschool. education during the pandemic or not, and assess language and executive functioning skills. The authors found that children's skills were stronger if they received group care during the pandemic, and these benefits were more evident in low-income children's families.
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Those most at risk appear to be children of color or those from low-income families. For example, a growing body of research shows that for school-aged children, distance learning can widen the already large learning and development gaps between children from affluent backgrounds. and low income, between white children and children of color. In the Netherlands, researchers found that children performed worse on national assessments in 2020 – compared with the previous three years – and academic failures were up to 60% greater for children from uneducated families.
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In parts of sub-Saharan Africa – including Ethiopia, Kenya, Liberia, Tanzania and Uganda – research shows that some children lose a lot of learning time in a year. And in the United States, after the first gap, a report by consulting firm McKinsey found that students of color started school in the fall three to five months behind in learning, while white students just one to three months later.
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MASK EFFECT
Children who have attended school or other group settings during the pandemic often interact with others wearing masks. An important question is whether masks, which obscure parts of the face important for expressing emotions and speech, could also affect children's emotional and language development.
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Edward Tronick, a psychologist at the University of Massachusetts Boston, has been bombarded with emails from parents and pediatricians concerned about the potential developmental effects of wearing masks. Tronick is famous for his 1975 'Still Face' experiment, which showed that when biological parents suddenly adopt a direct gaze when interacting with their infants, their children at first try to attract their attention , then slowly withdraws and becomes increasingly uncomfortable and wary.
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Tronick decided to see if masks would have the same effect. With his colleague, psychologist Nancy Snidman, he conducted an experiment (not yet peer-reviewed) in which parents used smartphones to record interactions with their children in advance, during and after they wear masks. Although infants notice when their parents wear a mask – they will quickly change facial expressions, look away or point at the mask – they will then continue to interact with their parents as before. Tronick says the mask only blocks one channel of communication. The masked parent still says, “I'm still interacting with you, I'm still here with you, I'm still connected to you.”
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Masks also do not appear to have much effect on emotional perception or language. A study published in May reported that two-year-old children could still understand what adults said when wearing masks. Lead author Leher Singh, a psychologist at the National University of Singapore, said children “compensate for information deficits more easily than we think.” Researchers in the US found that, although face masks made it harder for school-aged children to sense the emotions of adults – the majority of children were still able to make accurate inferences.
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“There are many other cues that children can use to analyze how others are feeling, like facial expressions,” said study author Ashley Ruba, a postdoctoral fellow at the University of Wisconsin–Madison. show voice, body expression, context.”
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PREGNANCY AND STRESS
Other researchers are keen to know whether the pandemic could affect children's development before they are born. Catherine Lebel, a psychologist who runs the Developmental Neuroimaging Laboratory at the University of Calgary in Canada, and her colleagues surveyed more than 8,000 pregnant people during the pandemic. Nearly half reported symptoms of anxiety, while a third reported symptoms of depression – a much higher rate than in pre-pandemic years. How does this stress affect the baby in the womb?
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To find out the cause, researchers used MRI images to scan the brains of 75 children 3 months after birth. In a preprint posted in October, they found that children born to people who reported prenatal distress – more symptoms of anxiety or depression – showed negative results. Different structural connections between their amygdala, a brain region involved in emotional processing, and their prefrontal cortex, an area responsible for executive functioning skills.
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In a previous small study, Lebel and her team found a link between prenatal depression and differences in brain connectivity in those areas, and suggested that in boys, These brain changes correlate with aggressive and hyperactive behavior in preschool age. Other groups have found that changes in connectivity between these regions in adults are risk factors for depression and anxiety. “Those are areas that are involved in emotional processing and a lot of different behaviors,” Lebel said.
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Other studies have found similar links between prenatal stress and child development. Livio Provenzi, a psychologist at the IRCCS Mondino Foundation in Pavia, Italy, and his colleagues have observed that the three-month-old babies of people who experienced a lot of stress and anxiety during pregnancy experienced more problems regulating emotions and attention. For example, to maintain the baby's attention on social stimuli and be less soothed – compared to infants of people who were less stressed and anxious during pregnancy.
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Thomason is running her own study to evaluate the impact of maternal stressors on children's brains and behavior. She notes that, although there are many concerns about how prenatal stress may affect children during the pandemic, such early findings do not mean that children will struggle in the future. the rest of his life. “Children are very adaptable and resilient. And we hope that things will improve and children will be able to be resilient in the face of many of the things that have happened,” she said.
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Indeed, research on historical disasters shows that, although stress in the womb can harm babies, it does not always have long-term effects. Children born to people who experienced significant stress as a result of the 2011 floods in Queensland, Australia, showed deficits in social and problem-solving skills at just 6 months of age , compared to children born to less stressed individuals. However, by 30 months, these outcomes were no longer correlated with stress, the more parents were responsive to their infants' and toddlers' needs.
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CAUTION AND ACTION
Research on infants during the pandemic shows a mixed picture and scientists say it is too early to draw meaningful explanations. Catherine Monk, a medical psychologist who works with Dimitriu at NewYork–Presbyterian, said some of these initial, often unpublished findings may not reflect reality.
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For example, the parents who choose to participate in some initial studies may not be a representative sample, Monk said. Perhaps they were worried about their kids on the basis of the behavior they were seeing. Furthermore, she said, the results of head-to-head studies like Deoni's could be influenced by mask wearing — perhaps not much, but enough to skew the results.
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Researchers and funders are launching major studies and collaborations that could help build a clearer picture. The U.S. National Institute on Drug Abuse is funding several studies through the Brain Development and Healthy Children Study. These will look at how maternal stress and substance use during the pandemic affects children's development. Additionally, alliances and conferences have been formed to bring researchers together and share emerging data. In March 2020, Thomason founded the international Generation COVID Research Alliance, bringing together researchers from 14 countries studying families with young children during the pandemic. The alliance, which is hosting a research summit in November 2021, includes researchers in North and South America, Europe, Australia, Asia, the Middle East and Africa.
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Parents can make progress by playing and talking with their young children regularly, and creating opportunities for them to play with others in a safe environment. Policy changes to support families and children can also make a difference. Lebel's research shows that meaningful social support, such as from a husband or close friend, during pregnancy helps reduce prenatal distress. “We can do so much more in the prenatal care ecosystem,” Monk said. Researchers also debate interventions that support families immediately after birth. Provenzi's research has found that people who have just given birth and are visited at home by nurses and neonatologists are less stressed and anxious than those who are not.
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Overall, researchers say most children are likely to be fine – but more than usual appear to be struggling. And if we want to support those who are falling behind, we should ideally intervene early. “The kids are definitely resilient,” Deoni said. “But at the same time, we also recognize the importance of the first 1,000 days of a child's life as an important early foundation.” The first babies of the pandemic, born in March 2020, were at this time more than 650 days old.
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Translator: Hồ Thủy Tiên
Source of article: https://www.nature.com/articles/d41586-022-00027-4
