Children continuously exposed to higher levels of naturally occurring radon gas in their homes may experience changes in how their brains develop key attention and problem-solving skills. A recent study published in NeuroImage found that youths with greater chronic radon exposure showed altered brain wave patterns when completing tasks that require high levels of focus. These electrical alterations also influenced how accurately the children performed behavioral tasks, suggesting that typical brain maturation could be disrupted by the common environmental toxin.
Radon is a colorless, odorless gas produced by the natural breakdown of radioactive materials in the earth. It is well known as a leading cause of lung cancer, but its potential impact on brain development remains largely unexplored. Because radon often seeps into homes and accumulates over time, children are particularly vulnerable to its effects as their brains are still undergoing critical growth phases.
Despite its prevalence, public awareness regarding the risks of indoor radon remains relatively low. Estimates suggest that one in fifteen homes within the United States has an indoor radon concentration that exceeds the action limits recommended by the Environmental Protection Agency. Many families never test their residences for the invisible gas.
Researchers wanted to understand if chronic background radiation from radon affects a set of mental skills called cognitive control. These skills allow people to filter out distractions, resolve conflicting information, and maintain focus on a specific goal. In a child’s day-to-day life, cognitive control is essential for functioning in a classroom, finishing homework, and managing emotional responses.
Haley R. Pulliam, a researcher at Boys Town National Research Hospital, led a team to investigate this question. Along with Brittany K. Taylor and their colleagues, Pulliam sought to measure whether varying levels of indoor radon relate to the brain activity supporting these advanced mental processes.
The investigators recruited nearly sixty young participants between the ages of six and fourteen. To estimate the amount of radiation each child experienced at home, the parents placed short-term radon testing kits on the lowest livable level of their houses for several days. The researchers then calculated an exposure index based on these laboratory results and the number of years each child had lived in that specific home.
To analyze brain function, the children completed a specialized computer game known as a Simon task while seated inside a brain scanning machine. The machine uses a technique called magnetoencephalography to harmlessly measure the tiny magnetic fields produced by the brain’s electrical activity. This technology can track rapid brain waves on a millisecond-by-millisecond basis as participants react to fast-paced tests.
During the task, a row of three numbers appeared on a screen. The children had to press a button corresponding to the single number that was different from the two surrounding numbers. To create a mental challenge, the test occasionally places the target number in spatial locations that do not match the correct button response.
Participants must fight the urge to respond based on where the number is located on the screen, and instead focus only on the number’s identity. This requires the brain to resolve a spatial conflict and suppress an automatic physical reaction. The scanning machine mapped how different brain regions communicated through rhythmic brain waves while the children attempted to filter out the spatial interference.
The research team discovered an association between radon exposure and specific alterations in the children’s brain activity. The nervous system communicates by firing electrical impulses in synchronized rhythms, often categorized by their frequencies. During the focus-intensive tasks, children with higher radon exposure showed unusual patterns in their alpha, theta, and gamma frequency bands.
The electrical alterations were spread across multiple networks. Some changes occurred in the occipital and motor regions of the brain. The occipital lobe handles visual processing, while the motor cortex plans physical movements. This suggests that continuous background radiation might affect how the brain interprets basic visual cues and translates them into physical actions to overcome the test’s spatial interference.
Other changes appeared in the prefrontal cortex, a region responsible for advanced thinking and attention. In several of these frontal areas, youths with more radon exposure exhibited weaker brain wave responses during the difficult portions of the task. Conversely, they showed abnormally strong brain wave activity during the easy baseline portions of the test.
The authors suggest this brain wave pattern resembles a biological compensation mechanism often seen in older adults experiencing age-related neurocognitive changes. Because the children’s brains were working harder just to handle simple baseline tasks, they had fewer neural resources available when the test became demanding. In other words, their cognitive resources were depleted earlier than those of children with lower exposure histories.
The data also revealed that radon exposure appeared to alter the normal developmental curve of the brain’s attention networks. In typically developing youths, the brain wave responses used for solving spatial conflicts become more refined and efficient as the children mature from childhood into adolescence.
Yet, among the children with the highest radon exposure in this sample, these developmental trajectories were either flattened or reversed in several key brain regions. Brain areas that usually take on heavier workloads as a child gets older failed to show the expected maturational changes in children who grew up in high-radon environments.
These brain activity changes translated into observable behavioral outcomes. The researchers determined that the altered electrical activity served as a bridge between the environmental gas exposure and the participants’ reaction times. Younger children with high radon exposure relied heavily on certain frontal brain regions during the test while still performing relatively poorly compared to peers with lower exposure.
The authors noted a few limitations regarding how the study measured environmental toxins. The commercially available testing kits only captured a brief snapshot of radon levels over a few days, which can fluctuate due to weather, open doors, or building ventilation. The study also did not measure radiation levels at the children’s schools or prior residences.
Future studies will need to track a larger group of children over a longer period of time. This longitudinal approach would help researchers observe how brain networks mature over many years while facing continuous radiation. Additional investigation is also needed to see if these early neural differences relate to developmental conditions like attention-deficit hyperactivity disorder over a person’s lifespan.
The study, “Chronic radon exposure is associated with developmental alterations to neural and behavioral indices of cognitive control,” was authored by Haley R. Pulliam, Christine M. Embury, Maggie P. Rempe, Hannah J. Okelberry, Danielle L. Rice, Anna T. Coutant, Ryan Glesinger, Tony W. Wilson, and Brittany K. Taylor.