Post-Acute Cortical Thickness in Children with Mild Traumatic Brain Injury versus Orthopedic Injury

Abstract

Studies of brain morphometry may illuminate the effects of pediatric mild traumatic brain injury (TBI; e.g., concussion). However, no published studies have examined cortical thickness in the early injury phases of pediatric mild TBI using an appropriate comparison group. The current study used an automated approach (i.e., FreeSurfer) to determine whether cortical thickness differed in children following a mild TBI or a mild orthopedic injury (OI), and to examine whether post-acute cortical thickness predicted post-acute and chronic post-concussive symptoms (PCS). Children ages 8.00-16.99 years with mild TBI (n = 136) or OI (n = 70) were recruited at emergency department visits to two children's hospitals, during which parents rated children's pre-injury symptoms retrospectively. Children completed a post-acute (3-24 days post-injury) assessment, which included a 3 Tesla MRI, and 3- and 6-month post-injury assessments. Parents and children rated PCS at each assessment. Cortical thickness was estimated using FreeSurfer. Linear mixed effects and multi-variable negative binomial regression models were used to test study aims, with false discovery rate (FDR) correction for multiple comparisons. Groups differed significantly on left parietal cortical thickness (TBI > OI) after FDR correction. Cortical thickness also varied by brain subregion and age, but not sex. Groups differed significantly on PCS post-acutely (TBI > OI), but not at 3 or 6 months. Right frontal thickness was positively related to post-acute PCS in both groups. Right cingulum thickness predicted chronic PCS in the OI group only. Results highlight the complexity of predicting outcomes of pediatric mild TBI from post-acute neuroimaging biomarkers.

Keywords: cortical thickness; mild TBI; orthopedic injury; pediatric TBI; structural MRI.

FIG. 1.

Summary of results for Aim 1: the mild TBI group showed (A) robustly (adjusted p value <0.05) increased left parietal cortical thickness and (B) less robustly (unadjusted p value <0.05) increased cortical thickness in the right parietal and frontal cortices as compared to the OI group.

FIG. 2.

Graphs illustrating the significant group by average thickness of the right cingulum cortex (shown in the inset) interaction on children's ratings of post-acute somatic (top) and 6-month cognitive (bottom) post-concussive symptoms.