Research Reports - Orbitofrontal cortical thinning and aggression in mild traumatic brain injury patients
Brain Behav. 2016 Sep 28;6(12):e00581. doi: 10.1002/brb3.581. eCollection 2016.
Epstein DJ(1), Legarreta M(2), Bueler E(2), King J(3), McGlade E(4),
INTRODUCTION: Although mild traumatic brain injury (mTBI) comprises 80% of all
TBI, the morphological examination of the orbitofrontal cortex (OFC) in relation
to clinical symptoms such as aggression, anxiety and depression in a strictly
mTBI sample has never before been performed.
OBJECTIVES: The primary objective of the study was to determine if mTBI patients
would show morphological differences in the OFC and if the morphology of this
region would relate to clinical symptoms.
METHODS: Using structural images acquired in a 3T MRI machine, the cortical
thickness and cortical volume (corrected for total brain volume) of the OFC was
collected for healthy control (N = 27) subjects and chronic mTBI (N = 55)
patients at least one year post injury. Also, during clinical interviews,
measures quantifying the severity of clinical symptoms, including aggression,
anxiety, and depression, were collected.
RESULTS: MTBI subjects displayed increased aggression, anxiety, and depression,
and anxiety and depression measures showed a relationship with the number of mTBI
in which the subject lost consciousness. The cortical thickness of the right
lateral OFC displayed evidence of thinning in the mTBI group; however, after
correction for multiple comparisons, this difference was no longer significant.
Clinical measures were not significantly related with OFC morphometry.
CONCLUSION: This study found increased aggression, anxiety, and depression, in
the mTBI group as well as evidence of cortical thinning in the right lateral OFC.
The association between clinical symptoms and the number of mTBI with loss of
consciousness suggests the number and severity of mTBI may influence clinical
symptoms long after injury. Future studies examining other brain regions involved
in the production and regulation of affective processes and inclusion of subjects
with well-characterized mood disorders could further elucidate the relationship
between mTBI, brain morphology, and clinical symptoms.