Differences in the Subcortical White Matter Integrity Based on the Disorder of Consciousness at the Chronic Stage of Diffuse Axonal Injury: A Tract-Based Spatial Statistics Study

Abstract

Highlights What are the main findings? Tract-based spatial statistics (TBSS) revealed that DAI patients with a disorder of consciousness (DOC) exhibit significantly lower fractional anisotropy (FA) values in 44 of 48 subcortical white matter regions compared to non-DOC patients. Extensive microstructural degradation was confirmed globally, as the DOC group demonstrated significantly lower FA values across all 48 regions when compared to healthy controls. What are the implications of the main findings? The severity of impaired consciousness in chronic DAI directly reflects the extent of microstructural injury across broad subcortical neural networks, rather than localized focal damage. Widespread subcortical white matter degradation disrupts the complex interplay of diverse neural networks (e.g., thalamocortical projections, ARAS, fronto-parietal networks) necessary for conscious perception, providing a crucial neuroanatomical basis for understanding consciousness disorders following DAI. Abstract Background and Objectives: In this study, we investigate the relationship between the state of consciousness and the whole white matter integrity at the chronic stage in diffuse axonal injury (DAI) patients, using tract-based spatial statistics (TBSS). Materials and Methods: Twenty-seven chronic DAI patients and 22 healthy controls were enrolled. Patients were divided into a disorder of consciousness (DOC) group (n = 11, Coma Recovery Scale-Revised [CRS-R] score < 23) and a non-DOC group (n = 16, CRS-R score = 23). Fractional anisotropy (FA) values across 48 subcortical white matter regions of interest (ROIs), defined by the Johns Hopkins University atlas, were analyzed using TBSS to evaluate group differences. Results: The groups significantly differed on FA values of 48 ROIs (Pillai’s trace = 1.000, p < 0.05). The Tukey’s HSD test revealed that the FA values of 44 ROIs (except for the column and body of fornix, right corticospinal tract, left retrolenticular part of internal capsule, and left uncinate fasciculus) among the 48 ROIs of the DOC group were significantly lower than those of the non-DOC group, whereas the FA values of all 48ROIs of the DOC group were significantly lower than those of the control group (p < 0.05). On the other hand, except for the bilateral corticospinal tract, the FA values of 46 ROIs among the 48 ROIs of the non-DOC group were significantly lower than those of the control group (p < 0.05). Conclusions: In DAI patients, the state of consciousness was related to injury severity in most subcortical neural structures.