White matter deficits underlie the loss of consciousness level and predict recovery outcome in disorders of consciousness

This study aimed to identify white matter (WM) deficits underlying the loss of consciousness in disorder of consciousness (DOC) patients using Diffusion Tensor Imaging (DTI) and to demonstrate the potential value of DTI parameters in predicting recovery outcomes of DOC patients. With 30 DOC patients (8 comatose, 8 unresponsive wakefulness syndrome/vegetative state, and 14 minimal conscious state) and 25 patient controls, we performed group comparison of DTI parameters across 48 core WM regions of interest (ROIs) using Analysis of Covariance. Compared with controls, DOC patients had decreased Fractional anisotropy (FA) and increased diffusivities in widespread WM area. The corresponding DTI parameters of those WM deficits in DOC patients significantly correlated with the consciousness level evaluated by Coma Recovery Scale – Revised (CRS-R) and Glasgow Coma Scale (GCS). As for predicting the recovery outcomes (i.e., regaining consciousness or not, grouped by their Glasgow Outcome Scale >2 or not) at 3 months post scan, radial diffusivity of left superior cerebellar peduncle and FA of right sagittal stratum reached an accuracy of ~87.5% and ~75% respectively. Our findings showed multiple WM deficits underlying the loss of consciousness level, and demonstrated the potential value of these WM areas in predicting the recovery outcomes of DOC patients who have lost awareness of the environment and themselves.