Longitudinal Relationships of Amygdalar and Hippocampal Volumes With Anxiety After Pediatric Traumatic Brain Injury

Traumatic brain injury (TBI) often involves injury to limbic structures that may be linked to posttraumatic psychological health difficulties. The authors investigated whether the relationship of amygdala and hippocampal volumes with anxiety differed among children with TBI versus children without a history of TBI over time since injury.

Structural MRI scans were acquired for children ages 8-15 years at 7 weeks (time point 1) and 14 months (time point 2) after a TBI (N=51) as well as for age-matched healthy control (HC) children (N=36). The Screen for Child Anxiety Related Emotional Disorders (SCARED) was administered at both time points. Generalized linear models were used to evaluate the relationship of limbic volumes, experimental group, time of scan, and their interactions with SCARED scores. Pubertal status at time point 1, sex, and total gray matter volume were included as covariates.

The group × volume × time interaction was statistically significant for both structures bilaterally. Relative to the HC group, children with TBI showed altered directionality of the relationship of amygdala and hippocampal volumes with SCARED scores that changed between the two time points. During the subacute stage of recovery, higher self-reported anxiety was associated with larger amygdala and hippocampal volumes. During the chronic stage, higher anxiety was associated with lower volumes. SCARED scores were higher among girls than among boys when limbic volumes were controlled for.

TBI significantly affected the typical relationship between amygdala and hippocampal volumes and anxiety scores, suggesting that limbic volumes may serve as markers of later developing psychological health.