Joseph Delic MD, Presenter: Nothing to Disclose

Lea M. Alhilali MD, Abstract Co-Author: Nothing to Disclose

Michael W. Collins PhD, Abstract Co-Author: Nothing to Disclose

Saeed Fakhran MD, Abstract Co-Author: Nothing to Disclose

To determine if unique white matter injury patterns underlie neuropsychiatric symptoms after mild traumatic brain injury (mTBI) utilizing tract-based spatial statistics (TBSS) analysis of diffusion tensor imaging (DTI).

DTI and serial neurocognitive testing with the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) were obtained in 38 mTBI patients with irritability, 32 with depression, 18 with anxiety, and 8 with anger/aggression. Controls consisted of 37 mTBI patients without irritability, 43 without depression, 57 without anxiety, and 67 without anger/aggression, respectively. Fractional anisotropy (FA) maps were generated and analyzed using TBSS regression analysis utilizing a general linear model and unpaired t-test. DTI abnormalities were correlated with symptom severity, neurocognitive test scores, and time to recovery with Pearson’s correlation coefficient.

As compared to controls, mTBI patients with depression had decreased FA values in the superior longitudinal fasciculus, white matter around the nucleus accumbens, and anterior limb of the internal capsule (p<0.05). Patients with anxiety had diminished FA values in the posterior cingulate gyrus and cerebellum (p<0.05), while patients with anger/aggression had decreased FA in the inferior longitudinal fasciculus of the visual limbic pathway. No regions of significantly decreased FA were seen in patients with irritability relative to controls. FA values of the white matter in the region of the nucleus accumbens inversely correlated with recovery time in patients with depression (R=-0.478; p=0.008).

Unique white matter injury patterns were seen for three major post-traumatic neuropsychiatric symptoms. Involvement of the nucleus accumbens in depression after mTBI may suggest an underlying dysfunctional reward circuit. Similarly, injury to the cerebellum in post-traumatic anxiety correlates well with known abnormalities seen in this region in anxiety patients in the population at large. Injury to the visual limbic pathway in post-traumatic anger/aggression suggests a structure/function relationship between this region and the resulting symptomatology.

Specific white matter injury patterns underlying individual neuropsychiatric symptoms are highly likely to provide new targets for therapeutic interventions, in addition to fundamentally advancing the field of brain trauma research.

Delic, J, Alhilali, L, Collins, M, Fakhran, S, Detection of Unique White Matter Injuries Underlying Neuropsychiatric Symptoms after Mild Traumatic Brain Injury.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14012107.html