Investigating acute-to-subacute neuroanatomical outcomes and the role of sex and age in adolescent concussion: A PedCARE+MRI substudy

Background Limited research has examined acute-to-subacute neuroanatomical trajectories following adolescent concussion. To investigate acute-to-subacute longitudinal changes in cortical thickness and subcortical volume following adolescent concussion, we compared neuroanatomical trajectories relative to orthopedic injury (OI) from 72 h to 4 weeks post-injury, and explored moderation by age and sex. Methods Youth aged 10–17 years with an acute concussion or OI were recruited from a pediatric emergency department and completed acute and subacute T1-weighted MRI scans. Sixty-seven youth with concussion and 31 youth with OI were included in analyses. Results Time did not moderate group differences in cortical thickness and volume. No main effects of group were found across cortical regions, with no moderating effects of age or sex. Youth with concussion demonstrated persistently reduced hippocampal volume relative to OI across time. Age, but not sex, further moderated group differences in hippocampal volume, with similar trajectories below 12 years of age, but progressively greater hippocampal volume in OI relative to concussion around 13 years of age and older. Increasing age was associated with cortical thinning across cortical regions, except the middle frontal gyrus, irrespective of group. Conclusion These findings suggest cortical structures may not be affected within the first 4 weeks post-injury. Hippocampal volume was reduced in youth with concussion aged approximately 13 years and older from 72 h through 4 weeks post-injury, suggesting deviation from the positive age–hippocampal volume relationship in OI. This age-dependent pattern may suggest an acute-to-subacute neurodevelopmental vulnerability of the hippocampus during early adolescence following concussion.