Early cortical thickness change after mild traumatic brain injury following motor vehicle collision

Abstract

In a motor vehicle collision (MVC), survivors often receive mild traumatic brain injuries (mTBI). Although there have been some reports of early white matter changes after an mTBI, much less is known about early cortical structural changes. To investigate early cortical changes within a few days after an MVC, we compared cortical thickness of mTBI survivors with non-mTBI survivors, then reexamined cortical thickness in the same survivors 3 months later. MVC survivors were categorized as mTBI or non-mTBI based on concussive symptoms documented in emergency departments (EDs). Cortical thickness was measured from MRI images using FreeSurfer within a few days and again at 3 months after MVC. Post-traumatic stress symptoms and physical conditions were also assessed. Compared with the non-mTBI group (n = 23), the mTBI group (n = 21) had thicker cortex in the left rostral middle frontal (rMFG) and right precuneus gyri, but thinner cortex in the left posterior middle temporal gyrus at 7.2 ± 3.1 days after MVC. After 3 months, cortical thickness had decreased in left rMFG in the mTBI group but not in the non-mTBI group. The cortical thickness of the right precuneus region in the initial scans was positively correlated with acute traumatic stress symptoms for all survivors and with the number of reduced activity days for mTBI survivors who completed the follow-up. The preliminary results suggest that alterations in cortical thickness may occur at an early stage of mTBI and that frontal cortex structure may change dynamically over the initial 3 months after mTBI.

Keywords: cortical thickness; mild TBI; motor vehicle collision; progression; subacute.

FIG. 1.

Vertex-based comparison of cortical thickness in the mild traumatic brain injury (mTBI) and non-mTBI groups at initial days after motor vehicle collision. Numbers 1–3 correspond respectively to the suprathreshold clusters in right precuneus, left rostral middle frontal gyrus, and left middle temporal gyrus. Color image is available online at www.liebertpub.com/neu

FIG. 2.

Relationship between post-traumatic stress disorder Checklist-Stressor Version (PCL) scores and the regional mean cortical thickness of right precuneus region (cluster 1) defined from the vertex-based group difference at initial magnetic resonance imaging (MRI) session. The positive correlation is significant (R=0.37, df=40, p=0.02) across all survivors (mild traumatic brain injury [mTBI] and non-mTBI). ROI, region of interest.

FIG. 3.

Relationship between the number of reduced usual activity days over the initial 3 months after motor vehicle collision and the regional mean cortical thickness of right precuneus region (cluster 1) in the mild traumatic brain injury (mTBI) survivors. The positive correlation was significant (Spearmas Rho test, R=0.715, n=11, p=0.01) in mTBI group, but correlation in the non-mTBI group was not significant. ROI, region of interest.