Abstract Details

Imaging data was available for 44 professional rugby players, including 21 imaged within one week of mild-probable traumatic brain injury (sub-acute mTBI), and 47 healthy controls, including 15 non-collision-sport athletes. Whole-cortex analyses comparing cortical thickness in rugby players with controls were performed in Freesurfer. This was followed by region of interest (ROI) analyses, constrained to ROIs selected on the basis of the whole-cortex results. This entailed multi-variate linear regression models investigating the independent effects of rugby participation, sub-acute mTBI, sporting participation, as well as biomarkers of axonal injury (white matter diffusion weighted MRI and plasma neurofilament light) and neuroinflammation (plasma glial fibrillary acidic protein).

Whole-cortex analysis revealed evidence of lower cortical thickness in non-acutely injured rugby players compared to controls in a cluster centered around the right precentral region (cluster size=4878 mm², p-value corrected for multiple comparisons=0.014). ROI analysis revealed evidence that rugby participation independently predicted lower cortical thickness in the right inferior precentral sulcus (p=0.003). Conversely, sub-acute mTBI independently predicted higher cortical thickness in the same region (p=0.015). Furthermore, there was evidence plasma glial fibrillary acidic protein was positively associated with right inferior precentral sulcus thickness in a subset of players with sub-acute mTBI (n=14, p=0.001).

In this cross-sectional study, we present evidence that active elite rugby participation predicts alterations in right precentral thickness. Larger scale longitudinal data are required to replicate these findings, and understand their long-term implications.