Abstract
Objective: Explore the relationship between structural integrity, microvascular function, and neurocognitive performance in chronic traumatic brain injury (TBI).
Background: Previous research has shown multifocal vascular and microstructural injury in chronic TBI. The relationship between these injuries and chronic neurocognitive symptoms is unknown.
Design/Methods: Functional MRI-Blood-Oxygen-Level dependent (BOLD) and Diffusion Tensor Imaging (DTI) were performed on 27 chronic TBI subjects and 14 healthy controls. Each image was segmented into anatomical regions of interest (ROI) with Freesurfer. Cerebrovascular reactivity (CVR), cerebral blood flow (CBF), fractional anisotropy (FA), and mean diffusivity (MD) were measured in each region. Nonparametric spearman rho correlations were calculated (Version 7, Graphpad, Inc) comparing 32 selected ROI with scores from 7 neuropsychological assessments (Trail-Making Test (TMT) A and B, California Verbal Learning Test, Wide Range Achievement Test, and Wechsler Adult Intelligence Scale). Post-concussive symptoms (PCS) were assessed using the Brief Symptom Inventory-Somatic and Rivermead Post-Concussion Questionnaire.
Results: CVR in the temporal, frontal, cingulate, and global white matter (WM) regions were significantly correlated with several neuropsychiatric assessment scores. A significant negative correlation was found between CVR and TMT-B in the inferior temporal lobe (Right: Rs= −0.42; p=0.03, Left: Rs=−0.39; p=0.05). Positive correlations were seen between FA and neuropsychiatric assessments in frontal, cingulate, and white matter regions. Global CVR, grey matter CVR, and CVR values in subcortical regions (hippocampus, amygdala, thalamus, caudate, putamen) were positively correlated with PCS self-report (p<0.05). Few significant correlations were seen between neuropsychological testing variables and CBF or MD.
Conclusions: Vascular reactivity and microstructural integrity within multiple regions of the brain are associated with neurocognitive symptoms in chronic TBI patients. While CVR is decreased in chronic TBI, this study demonstrates that increased CVR, especially within subcortical regions, is associated with more PCS. Further studies are needed to explore the effects of cerebral vascular injury in chronic TBI.
Disclosure: Dr. Woodson has nothing to disclose. Dr. Haber has nothing to disclose. Dr. Amyot has nothing to disclose. Dr. Fleshner has nothing to disclose. Dr. Silverman has nothing to disclose. Dr. Kenney has nothing to disclose. Dr. Moore has nothing to disclose. Dr. Chou has nothing to disclose. Dr. Pham has nothing to disclose. Dr. Sangobowale has nothing to disclose. Dr. Diaz-Arrastia has nothing to disclose.
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