Researchers who focus on child development wonder if the outbreak will affect brains and behaviors.
Like other pediatricians, Dani Dumitriu was incapacitated when she first saw the coronavirus in her room. She was relieved that most of the newborns exposed to the new crown virus in their hospital were not in serious trouble. Doctors who already have some knowledge of viruses such as Zika that cause birth defects are particularly wary of abnormalities.
However, the trend seen later was very faint and hidden. Since late 2017, Dumitriu and her team at New York-Presbyterian Morgan Stanley Children's Hospital have been collecting infant and toddler development data for two years, and they have been analyzing the communication and motor abilities of infants aged 6 months and younger. Dumitriu thinks it would be interesting to compare babies born before the pandemic with babies born during the pandemic. So she asked her colleague Morgan Firestein, a postdoctoral researcher at Columbia University in New York, to see if there were differences in neurodevelopment between the two groups of babies.
A few days later, Firestein panicked and called Dumitriu. Dumitriu recalled, "She said, 'Something went wrong, I didn't know what to do, the epidemic not only had an impact, but it was a big impact.'" She had hardly slept that night, flipping over and over to look at the data. Babies born during the pandemic scored lower on average in large movements, fine motor and communication skills compared to babies born before the pandemic (parents of both groups scored using ready-made questionnaires) [1]. This result has nothing to do with whether the birth parents have been infected with the new crown, and it looks more like it is related to the general environment of the epidemic.
Dumitriu was stunned. She said, "Our reaction was, oh my God, there are hundreds of millions of babies here. ”
A teacher in protective clothing teaches a little girl at her home in Cali, Colombia.
图 | Luis Robayo/AFP/Getty
Although children are generally doing well after infection with COVID-19, preliminary studies have shown that outbreak-related stress during pregnancy may have adverse effects on fetal brain development in some children. Not only that, but exhausted parents and caregivers can change or reduce their interactions with their children, which may affect the child's physical and mental development.
Lockdowns, a crucial anti-epidemic measure, have forced many families with newborn babies into quarantine, depriving them of play time and interaction opportunities. Stress and lack of physical exertion also prevent many caregivers from providing the one-on-one companionship that infants and young children desperately need.
"Everybody wants to know if this has an impact on child development, parent-child relationships, peer relationships," said James Griffin, director of the Child Development and Behavior Division at the National Institute for Child Health and Human Development in Younis Kennedy," said James Griffin, director of the Child Development and Behavior Division at the National Institute for Child Health and Human Development in Maryland. ”
A number of teams around the world who are interested in these topics are publishing their findings, and new research projects are being launched. It's hard to see an absolute answer right now, not least because many of the labs that study child development have closed during the pandemic.
Some babies born in the past two years may show signs of stunting; others may be safe — if their caregivers can stay with them for longer at home, they can communicate more with their older siblings. As with health problems that have arisen during the pandemic, socioeconomic disparities clearly determine which groups are most affected. Early data showed that mask use had no adverse effects on children's emotional development, but prenatal stress may cause some changes in their brain connections. However, the specifics are unclear and many studies have yet to be peer reviewed.
Some researchers believe that many stunted children catch up and do not have long-term effects. "I don't think there is a generation that has been hurt by COVID-19." Moriah Thomason, a child and adolescent psychologist at New York University's Grossman School of Medicine, said.
Play time plummets
One lab that hasn't closed during covid-19 is the Advanced Baby Imaging Lab at Brown University in Rhode Island. Medical biophysicist Sean Deoni and colleagues used techniques such as magnetic resonance imaging (MRI) here to study how environmental factors affect infant brain development.
Although the pandemic has changed the way they study — fewer visitors and more cleaning — they still invite many babies to the lab to document their motor, visual and language abilities, part of a 7-year program by the National Institutes of Health (NIH) that focuses on early childhood development and its impact on health later in life.
However, as the outbreak continued, Deoni heard concerns from colleagues. "Our colleagues told me in private, 'How long have these kids been through the assessment?'" he said. ’”
Puzzled, he asked lab researchers to calculate and compare the baby's annual average score and variance in neurodevelopment. They found that the scores of babies born during the pandemic were much worse than those of babies born before the pandemic (see "Developmental Hypocity"). He said at the end of 2021, "The situation seems to have taken a sharp turn for the worse from the end of last year to the beginning of this year." When they compared the results of different groups, they found that babies born during the epidemic were nearly two standard deviations lower in a series of developmental tests similar to IQ tests than babies born before the epidemic. Their findings also included that infants in low-income households experienced the greatest declines; boys were more affected than girls[2]; and large motor skills were most affected.
Figure | Reference 2
At first, Deoni thought it was a matter of selectivity: families who came to the lab during the pandemic may have children who have some developmental problems themselves or have signs of it. But gradually, he found that selective bias could not explain the end result, because the children who came to evaluate were not different from their previous children in terms of background, childbirth outcomes, or socioeconomic status.
These effects may seem large, but some researchers believe that this does not necessarily lead to long-term problems. "Iq doesn't predict anything for babies," says Marion van den Heuvel, a developmental neuropsychologist at Tilburg University in the Netherlands, "and it's hard to say what this will do for their future." She noted that there was a study[3] that found that Romanian girls born in orphanages but adopted before the age of 2.5 were less likely to develop mental problems at age 4.5 than girls who had been living in orphanages. Although this is not the same thing as the epidemic, it shows that infants and young children will compensate for their previous difficulties after the restrictions disappear.
But worryingly, Deoni found that the longer the outbreak lasts, the more problems there are with children. "The extent is staggering." Deoni commented on the findings. The study is currently being revised in jama pediatrics.
When Deoni first published his findings on a preprint server,[2] the media erupted in panic and questioned by peers in the research community. Griffin said there was concern at the time that the results would be made public without proper peer review.
Assuming the findings hold water, why do babies born during the pandemic develop significant cognitive impairments – especially movement disorders? Deoni believes this is due to a lack of interpersonal communication. In an unpublished follow-up study, Deoni and his team recorded the time of parent-child interaction across families and found that in the past two years, parents have said less to their children, and what children have said to their parents, than before the pandemic. He also speculated that infants and young children's physical abilities were not fully exercised because they could not play with other children regularly and could not go to the outdoor playground. "Unfortunately, these skills are the foundation of other skills," he said. ”
Other recently published studies support the idea that a lack of interaction with peers can delay the development of some children. In a study published earlier this year, British researchers surveyed parents of 189 children aged 8 months to 3 years through a questionnaire, asked if their children had attended nursery or kindergarten during the pandemic, and assessed their language and executive abilities. The authors found that children who received group care during the pandemic were more empowered, and that the benefits were particularly pronounced among children from low-income backgrounds [4].
The children most likely to be delayed appear to come from people of color or from low-income families. For example, a growing body of research suggests that distance learning among school-age children may exacerbate the already large educational and developmental disparities between wealthy and low-income families, as well as between white and colored children. In the Netherlands, researchers found that the 2020 National Child Assessment was less than the previous three years, with children from less educated families being 60% worse [5].
Mask effect
Children who go to school or participate in other groups during the pandemic are generally wearing masks. There's a problem: parts of our face are important for expressing emotions and speaking, and covering our faces with masks may also affect our children's emotional and language development.
A masked mother in Houston, Texas, interacts with her daughter while waiting for the results of a nucleic acid test.
图 | Brandon Bell/Getty
Edward Tronick, a psychologist at the University of Massachusetts boston, received a flood of emails from parents and pediatricians who were concerned about the potential impact of masks on development. Tronick became a household name for his 1975 "Still Face" experiment, which showed that if a biological parent suddenly raised his face when interacting with a baby, their children would initially win their attention, but over time they would become distant, more angry, and more wary.
Tronick decided to investigate whether wearing a mask had a similar effect. He and his colleague, psychologist Nancy Snidman, conducted an experiment (which has not yet been peer-reviewed) in which parents used their phones to record their parent-child interactions before, during, and after they wore a mask. Although babies can see that adults are wearing masks—they have subtle changes in facial expressions, look away, or point at masks—they interact with adults as before. Masks only shut down one of the channels of communication, Tronick said, "parents who wear masks still say to babies, 'I'm still here, with you, playing with you.'" ’”
Masks also don't seem to have much effect on emotional or verbal cognition. A study published last May found that 2-year-olds could understand what adults wearing opaque masks were saying [9]. Study corresponding author Leher Singh, a psychologist at the National University of Singapore, said it was easier for children to compensate for missing information than we thought. Researchers in the United States have found that although masks make it harder for school-age children to detect changes in adult emotions — as difficult as facing adults wearing sunglasses — these children are still able to make correct judgments in most cases [10].
Study author Ashley Ruba, a postdoctoral researcher at the University of Wisconsin-Madison, said, "Children can also rely on many other clues to interpret other people's feelings, such as voice expression, body language, environment, etc."
Pregnancy and stress
Other researchers also wanted to find out whether the pandemic would affect children's development before they were born. Psychologist Catherine Lebel, head of the Developmental Neuroimaging Laboratory at the University of Calgary, Canada, and her colleagues surveyed more than 8,000 pregnant women during the pandemic, with nearly half of them reporting symptoms of anxiety and 1 in 3 developing depressive symptoms – much higher than the pre-pandemic rate. So, does this stress affect the fetus in their womb?
To find out, the team used magnetic resonance imaging to scan 75 babies who were just 3 months old. In a preprint paper published last October, they found that women with more prenatal stress — more anxiety or depressive symptoms — had different structural networks of amygdalas and prefrontal cortex than others. The amygdala is the brain region that processes emotions, while the prefrontal cortex is the area responsible for performing functions [11].
The brain scan image above shows the pattern of connection between the baby's amygdala and other brain regions. The stress associated with the outbreak experienced during pregnancy can weaken some babies' brain connections. Figure | Kathryn Manning
In a previous small study, Lebel and her team also found an association between prenatal depression and differences in brain connections in these brain areas, and suggested that these brain changes were associated with aggression and ADHD in preschool-age boys [12]. Other teams have also found that changes in these brain region connections in adults are risk factors for depression and anxiety [13]. Lebel said: "These areas are brain regions involved in processing emotions and many different behaviors. ”
Other studies have found a similar association between outbreak-related prenatal stress and child development. Livio Provenzi, a psychologist at the IRCCS Mondino Foundation in Italy, and colleagues found that their 3-month-old babies also had more problems with regulating mood and attention than women with less stress and anxiety during pregnancy—it was harder to maintain attention to social stimuli and to soothe them.[14]
Thomason is also conducting his own research to assess the effects of pregnancy stressors on children's brains and behaviors. She noted that while many people are concerned about the impact of prenatal stress on their babies, early studies like this don't mean they'll have problems growing up. "Children are very resilient and easy to recover," she said. We believe the situation will get better and these children have a strong tolerance for what has already happened. ”
Indeed, previous studies have shown that while stress in the womb can be detrimental to your baby, this effect sometimes doesn't last long. Among those who experienced the 2011 floods in Queensland, Australia, women who were under great stress gave birth to children who were more likely than women under less stress to have problem-solving and social skills barriers at 6 months of age.[15] However, by the time they reach 30 months of age, these levels of development are no longer associated with stress, parents respond more promptly to their babies' needs after birth, and their babies grow up to develop better [16].
Vigilance and action
The results of the study on the epidemic baby are mixed, and scientists believe that no meaningful conclusions can be drawn yet. Many of these unpublished early findings may not be representative of the reality, says Catherine Monk, a medical psychologist who worked with Dimitriu at the New York-Presbyterian Church.
For example, parents who choose to participate in some of the early studies may not be representative, Monk said. Maybe they were already worried after seeing their children's behavior. In addition, the results of studies such as those conducted by Deoni may be influenced by wearing masks — not necessarily large, but enough to bias the results.
Thomason's review of JAMA Pediatrics last year[17] mentions that researchers have an instinct to publish interesting findings that may have influenced these earlier studies. "Scientists' search for harmful effects is very fast," she said. These things are easier to attract attention and easier to publish in high-scoring journals. ”
Researchers and funders are conducting some large studies and collaborations to help gain a clearer understanding. The National Institute on Drug Abuse has funded several studies in its Healthy Brain and Child Development Study program. These studies will look at how pregnancy stress and substance abuse affect children's development. In addition, various organizations and conferences will bring researchers together to share the latest data. In March 2020, Thomason founded the international COVID Generation Research Alliance, which brings together researchers from 14 countries to study families with babies during the pandemic. The consortium hosted a research summit in November 2021 that attracted researchers from North America, South America, Europe, Australia, Asia, the Middle East and Africa.
Even if children's brains do suffer from the pandemic, we still have time to correct, Dumitriu said, "6 months old babies have very strong brain plasticity and we can change the direction they're headed." ”
To this end, parents can play with their babies often, talk to them, and give them the opportunity to interact with others in a safe environment. Policy changes that support families and children may also help. Lebel's research [11] found that meaningful social support during pregnancy, such as support from a partner or close friend, greatly reduces prenatal stress. Monk said: "There is still a lot that we can do in the ecosystem of prenatal care. The researchers also advocated for the introduction of family support measures immediately after women gave birth. Provenzi's study [14] found that people who had nurses and neonatal specialists follow up after giving birth were less stressed and anxious than those who did not.
Overall, researchers still believe that most children will be fine, but there may be many babies who are experiencing difficulties at the moment. If we want to help children who are stunted, the best way is to intervene as soon as possible. "Children are very resilient," Deoni says, "but at the same time, we also know that the first 1,000 days of life are key to early childhood development." As of now, the first outbreak babies born in March 2020 are 650 days old.
Children are a product of their surroundings, Deoni said, "and what we have to do is give them all kinds of stimulation, play with them and read books, and pamper them." ”
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The original article was published in a news feature of Nature on January 12, 2022, under the headline The COVID generation: how is the pandemic affecting kids' brains?
Originally written by Melinda Wenner Moyer