Link between mild traumatic brain injury, poor sleep, and MRI-visible perivascular spaces in Veterans.

Abstract

Impaired clearance of perivascular waste in the brain may play a critical role in morbidity after mild traumatic brain injury (mTBI). We aimed to determine the effect of mTBI on the burden of MRI-visible perivascular spaces (PVS) in a cohort of U.S. military veterans and whether sleep modulates this effect. We also investigated the correlation between PVS burden and severity of persistent postconcussive symptoms. Fifty-six Iraq/Afghanistan veterans received 3T MRI as part of a prospective cohort study on military blast mTBI. White matter PVS burden (i.e., number and volume) was calculated using an established automated segmentation algorithm. Multivariate regression was used to establish the association between mTBIs sustained in the military and PVS burden. Covariates included age, blood pressure, number of impact mTBIs outside the military, and blast exposures. Correlation coefficients were calculated between PVS burden and severity of persistent postconcussive symptoms. There was a significant positive relationship between the number of mTBIs sustained in the military and both PVS number and volume (p=0.04). A significant interaction was found between mTBI and poor sleep on PVS volume (p=0.04). A correlation was found between PVS number and volume, and severity of postconcussive symptoms (p=0.03). Further analysis revealed a moderate correlation between PVS number and volume, and balance problems (p<0.001). In Iraq/Afghanistan veterans, mTBI is associated with an increase in PVS burden. Furthermore, an interaction exists between mTBI and poor sleep on PVS burden. Increased PVS burden, which may indicate waste clearance dysfunction, is associated with persistent postconcussive symptom severity.