Pathological Changes Confirm the Neuropsychiatric Sequelae to mTBI
- There is now evidence of the neuropsychological sequelae related to mild traumatic brain injury (mTBI). Therefore it is imperative to inquire with your post-concussive patients and their family about behavior changes along with utilization of outcome measures, such as post-concussive assessment tools to detect these problems on initial presentation.
- This recent study with utilization of Diffusion Tension Imaging reveals changes in deep cerebral axonal degeneration (superior longitudinal fasciculus, nucleus accumbens, and anterior limb of the internal capsule) in mTBI depression patients as compared to those mTBI without depression.
- This provides evidence of the pathological changes that occur in mTBI which lead to neuropsychiatric symptomatology.
Purpose: To determine if a central axonal injury underlies neuropsychiatric symptoms after mild traumatic brain injury (mTBI) by using tract-based spatial statistics analysis of diffusion-tensor images.
Materials and Methods: The institutional review board approved this study, with waiver of informed consent. Diffusion-tensor imaging and serial neurocognitive testing with the Immediate Post-Concussion Assessment and Cognitive Testing evaluation were performed in 45 patients with mTBI (38 with irritability, 32 with depression, and 18 with anxiety). Control subjects consisted of 29 patients with mTBI without neuropsychiatric symptoms. Fractional anisotropy and diffusivity maps were analyzed by using tract-based spatial statistics with a multivariate general linear model. Diffusion-tensor imaging findings were correlated with symptom severity, neurocognitive test scores, and time to recovery with the Pearson correlation coefficient.
Results: Compared with control subjects, patients with mTBI and depression had decreased fractional anisotropy in the superior longitudinal fasciculus (P = .006), white matter around the nucleus accumbens (P = .03), and anterior limb of the internal capsule (P = .02). Patients with anxiety had diminished fractional anisotropy in the vermis (P = .04). No regions of significantly decreased fractional anisotropy were seen in patients with irritability relative to control subjects. Injury in the region of the nucleus accumbens inversely correlated with recovery time in patients with depression (r = −0.480, P = .005).
Conclusion: Unique white matter injury patterns were seen for two major posttraumatic neuropsychiatric symptoms. Injury to the cerebellar vermis in patients with mTBI and anxiety may indicate underlying dysfunction in primitive fear conditioning circuits in the cerebellum. Involvement of the nucleus accumbens in depression after mTBI may suggest an underlying dysfunctional reward circuit that affects the prognosis in these patients.
Lea M. Alhilali, MD, Joseph A. Delic, MD, Serter Gumus, MD, Saeed Fakhran, MD. Evaluation of White Matter Injury Patterns Underlying Neuropsychiatric Symptoms after Mild Traumatic Brain Injury. Radiology. 2015 Jun 16:142974. [Epub ahead of print]