Abstract :
[en] Introduction
We aim to shed light on the localization of brain alterations in Disorders of Consciousness (DoC), by quantitatively synthesizing existing structural, functional and molecular evidence in patients with unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS).
Methods
In January 2022, we used MEDLINE, Scopus and Embase to search for resting-state MRI and PET studies, involving adults with prolonged DoC, diagnosed based on a validated behavioural scale. Two referees independently screened studies and extracted coordinates of whole-brain, voxel-based comparisons between groups of patients and controls or patients subgroups. Coordinate-based meta-analysis was performed via activation likelihood estimation. The full protocol is available on PROSPERO (CRD42022327151).
Results
As of January 2023, of the resulting 2045 MRI and 753 PET studies, 15 MRI and 18 PET studies met criteria for inclusion, for a total of 454 UWS and 572 MCS patients and 277 controls (Fig. 1).
The primary analysis, including studies comparing DoC patients vs. controls, revealed brain alterations in cortical regions, medially (precuneus, posterior/middle cingulate gyrus) and laterally (angular gyri, inferior parietal lobules), and in subcortical regions (dorsomedial thalami and head of caudate nuclei) (Fig. 2).
Contrast analysis of UWS and MCS results revealed stronger brain alterations in UWS in the precuneus, posterior/middle cingulate gyrus, right angular gyrus and inferior parietal lobule, and dorsomedial thalami.
Conclusions
This meta-analysis provides the most extensive evidence to date on brain alterations in DoC, pointing at a specific set of regions, at cortical and subcortical level, as anatomical basis for DoC, with stronger alterations in UWS compared to MCS.
