White matter microstructural changes in post-traumatic headache: A diffusion tensor imaging (DTI) study.

Introduction: Post-traumatic headache (PTH) is a common consequence of mild traumatic brain injury (mTBI) that can severely impact an individual's quality of life and rehabilitation. However, the underlying neuropathogenesis mechanisms contributing to PTH are still poorly understood. This study utilized diffusion tensor imaging (DTI) to detect microstructural alterations in the brains of mTBI participants with or at risk of developing PTH.

Method: This study investigated associations between DTI metrics 1-month postinjury and pain sensitivity, as well as psychological assessments 6-months postinjury to identify differences between mTBI (n = 12) and healthy controls (HC; n = 10). MRI scans, including T1-weighted anatomical imaging and DTI were acquired at 1-month postinjury. Pain sensitivity assays included quantitative sensory testing and psychological assessment questionnaires at 1-month and 6-months postinjury.

Results: Significant aberrations of mean axial diffusivity in the forceps major were observed in mTBI relative to HCs at 1-month postinjury (p =0.02). Within the mTBI group, DTI metrics at 1-month postinjury were significantly associated (p's < 0.05) with pain-related measures and psychological outcomes at 6-month postinjury in several white matter tracts (right sagittal stratum, left anterior thalamic radiation, left corticospinal tract, left insula, left superior longitudinal fasciculus). Notably, the associations between DTI metrics at 1-month postinjury and pain-related measures at 6-month postinjury showed significant group differences in the right sagittal stratum (p's < 0.01), white matter tract in left insula (p < 0.04), and left superior longitudinal fasciculus (p's < 0.05).

Conclusion: This study suggests that "Post-Traumatic Stress Disorder for DSM-5" and "Center for Epidemiological Studies-Depression Scale" are the most sensitive psychological measures to early microstructural changes after mTBI, and that the DTI metrics are predictive of pain and psychological measures in mTBI. Together, these results suggest that white matter microstructure plays an important role in the PTH following mTBI.