Premature white matter microstructure in female children with a history of concussion

As maturation of the brain continues throughout development, there is a risk of interference from concussions which are common in childhood. A concussion can cause widespread disruption to axons and inflammation in the brain and may influence emerging cognitive abilities. Females are more likely to experience persistent problems after a concussion, yet the sex-specific impact of concussions on brain microstructure in childhood is not well understood. In children from a large population sample, this study (1) investigated differences in white matter and cortical microstructure between children with and without a history of concussion, and (2) examined relationships between altered brain microstructure and cognitive performance. Neurite density measures from diffusion weighted magnetic resonance imaging were examined in 9- to 10-year-old children in the Adolescent Brain Cognitive Development Study with (n = 336) and without (n = 7368) a history of concussion. (1) Multivariate regression models were used to investigate the relationships between concussion history, sex, and age in the deep white matter, superficial white matter, subcortical structures, and cortex. (2) Principal component analysis was performed on neurite density, and components were examined in relation to performance on the Flanker Inhibitory Control and Attention Task and the Pattern Comparison Processing Speed Task to investigate the relationship between altered neurite density and cognitive performance. Neurite density in all tissue types demonstrated robust positive relationships with age reflecting maturation of brain microstructure. (1) Comparisons between children with and without a history of concussion revealed higher neurite density in deep and superficial white matter in females with concussion. No group differences were observed in subcortical or cortical neurite density. (2) Higher neurite density in superficial white matter beneath the frontal and temporal cortices was associated with lower scores on the processing speed test in females with concussion, and higher scores on the processing speed test in males with concussion. These findings suggest that concussion in childhood leads to premature white matter maturation in females and that this may be associated with slower processing speed. These sex-specific effects on the developing brain may contribute to the enhanced vulnerability to persistent symptoms after concussion in females.