Environmental Exposures and Neuroimaging in Children with Neurodevelopmental Disorders: A Scoping Review.

PURPOSE OF REVIEW: Neurodevelopmental disorders (NDDs) such as autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) have been linked to environmental exposures, yet the underlying neurobiological mechanisms remain poorly understood. Magnetic resonance imaging (MRI) offers an important in vivo tool for examining how environmental neurotoxicants impact brain development. This scoping review synthesizes current evidence on the associations between air pollution, metals, environmental tobacco smoke, and endocrine-disrupting chemicals (EDCs) assessed from pregnancy through childhood and neuroimaging findings in children diagnosed with NDDs.

RECENT FINDINGS: We identified 14 studies examining associations between environmental exposures and MRI outcomes in children with NDDs. Air pollution exposure was linked to reduced volumes in the caudate nucleus and corpus callosum. Metal exposure was associated with changes in cortical thickness and functional connectivity, varying by metal and diagnosis. Tobacco smoke exposure correlated with reduced volumes in the cerebellum and frontal cortex and disruptions in white matter and neural networks. EDCs were linked to cortical thinning and altered task-related brain activity, with some studies reporting associations with symptom severity among children with ADHD. Overall, the literature suggests that exposure to neurotoxicants may disrupt brain development in children with NDDs. Future research should prioritize longitudinal, transdiagnostic designs with repeated exposure assessments and multimodal imaging, as well as advanced statistical modeling, to better capture the complex relationships between exposure and outcome. These findings underscore the importance of public health interventions to mitigate exposure to neurotoxicants and minimize potential neurodevelopmental risks.