White matter integrity correlates with residual consciousness in patients with severe brain injury

Previous studies have suggested that white matter disruption plays an important role in disorders of consciousness (DOC) after severe brain injury. Nevertheless, the integrity of white matter architecture supporting consciousness and its relations with clinical severity in patients with DOC remain to be established. In this study, diffusion tensor imaging (DTI) data was collected from 14 DOC patients and 15 healthy control subjects. We combined tract-based spatial statistics (TBSS) with region of interest (ROI) analysis to examine differences of DTI metrics on white matter skeletons between DOC patients and healthy controls, and the association between white matter integrity and patients' residual consciousness assessed by Coma Recovery Scale-Revised (CRS-R). We found that: (1) patients with DOC had widespread white matter integrity disruptions, especially in the fornix; (2) the alteration of white matter microstructure was mainly attributed to the increase in radial diffusivity, possibly reflecting demyelination; (3) the behavioral CRS-R assessment score was positively correlated with white matter integrity in the fornix, uncinate fasciculus, pontine crossing tract, and posterior limb of internal capsule. Our results suggest that despite the widespread abnormalities of white matter following severe brain injury, the impairment of consciousness is likely to result from disruptions of key pathways that link brain regions in distributed networks.