May 24, 2024

Family income appears to influence infants’ early brain activity and development

New research has found that family income is related to infant brain activity and its development over the first two years of life. Specifically, infants from lower-income families exhibited lower brain activity at around 2-3 months, but experienced a faster increase in brain activity from 2-9 months. The new findings have been published in the journal Developmental Cognitive Neuroscience.

To better understand early brain development, the researchers sought to conduct a comprehensive longitudinal study using EEG (electroencephalography) data to investigate the relationship between socioeconomic status and neural activity. By examining EEG power across different frequency bands over the first two years of life, the researchers aimed to understand how socioeconomic variables might impact brain development and how these associations may influence cognitive and language outcomes in infants.

The findings could contribute to a deeper understanding of the importance of early experiences in shaping brain development and potentially inform interventions to support optimal brain growth in children from diverse socioeconomic backgrounds.

“As a Developmental Behavioral Pediatrician, I see first-hand how important those early years are for development,” said study author Carol L. Wilkinson (@drcarolw), attending physician at Boston Children’s Hospital and assistant professor of pediatrics at Harvard Medical School. “Understanding how early environmental influences affect brain development is a first step in providing targeted resources to ensure that children reach their maximum potential.”

To conduct the study, the researchers analyzed EEG data (a non-invasive way to measure brain activity) from two groups of infants. The first group was recruited from a primary care center serving low-income families, and the second group was recruited from the Boston area, including both infants with and without familial risk for autism spectrum disorder (ASD).

The EEG data were collected at multiple time points, starting from 2 or 3 months of age and continuing until 24 months of age. The researchers used standardized developmental assessments to measure the infants’ cognitive and language skills at 24 months.

The researchers analyzed the EEG data from 161 infants in total using a growth curve model, which allowed them to track changes in brain activity over time. The researchers examined different frequency bands in the EEG data to understand how different cognitive and behavioral states are associated with brain development.

Wilkinson and her colleagues found that brain activity increased steadily in all babies during the first two years of life. There were two periods of growth: a sharp increase in brain activity from 2 to 9 months, and a slower but continued increase from 9 to 24 months.

Family income had an impact on the babies’ brain activity. Babies from families with higher income had higher brain activity at 2 to 3 months of age compared to babies from lower-income families. Additionally, babies from lower-income families had a faster increase in brain activity from 3 to 9 months. Family income was also linked to the babies’ verbal and non-verbal development at 24 months.

“The brain undergoes huge amounts of change in the first couple of years after birth, and this early brain development sets the foundation for more and more complex cognitive skills that are critical to our functioning as children, adolescents, and adults. We found that family income influenced infants’ early brain activity (measured by EEG power) and how that activity changed between 2-9 months of age,” Wilkinson told PsyPost.

“Specifically, we found that at the youngest age we measured (~2-3 months), infants from families with lower income had lower EEG power. This suggests that the impact of reduced income on infant brain development occurs very early on, and that both the prenatal and neonatal environment likely play a role. Income reflects many other things in an infant’s environment that may play a more direct role in brain development like malnutrition, housing, parental stress, exposure to toxins, and more.”

The researchers not only found that infants from families with lower income had lower brain activity at around 2-3 months of age but also observed that these infants experienced a more significant increase in brain activity between 2 and 9 months compared to infants from higher-income families.

“We also observed that lower income was associated with greater change in power between 2 and 9 months. One possible explanation for this is the ‘Stress Acceleration Hypothesis’ that theorizes that early adversity and stress leads to accelerated brain development,” Wilkinson explained.

According to this hypothesis, the brain’s response to stress and adverse environments might trigger adaptive mechanisms that drive faster changes in brain activity during the early stages of life. However, it is important to note that this is just a theoretical explanation and further research is needed to fully understand the underlying mechanisms behind these associations.

“A big caveat is that ‘lower income’ can represent many different things in an infant’s environment and it is unclear what related factors directly influence early brain developmental trajectories. In order to provide effective supports to families, it is important that we better understand this,” Wilkinson said.

“To do this, we need larger studies focused on infants whose families have limited resources so we can determine within those settings what factors play the biggest role in brain development and developmental outcomes. Unfortunately, many infant EEG studies are largely based on participants from middle to high income households with college or above levels of education. To answer these questions, we need to do a better job at partnering with families to participate in research studies. This is something we are really working hard to do.”

The study, “Associations between EEG trajectories, family income, and cognitive abilities over the first two years of life“, was authored by Carol L. Wilkinson, Lara J. Pierce, Georgios Sideridis, Mark Wade, and Charles A. Nelson.

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