Regional Homogeneity Alterations in Patients with Impaired Consciousness. An Observational Resting-State fMRI Study

Area of Science:

• Neuroscience
• Clinical Neurology
• Medical Imaging

Background:

• Differentiating minimally conscious state (MCS) from vegetative state/unresponsive wakefulness syndrome (VS/UWS) in disorders of consciousness (DOC) is clinically challenging.
• The neural underpinnings of awareness in DOC remain poorly understood, necessitating advanced diagnostic tools.

Purpose of the Study:

• To investigate disruptions in regional brain connectivity using regional homogeneity (ReHo) analysis in MCS and VS/UWS patients.
• To identify neuroimaging biomarkers for distinguishing between MCS and VS/UWS.

Main Methods:

• Resting-state functional magnetic resonance imaging (fMRI) was employed.
• Regional homogeneity (ReHo) analysis was performed on 14 MCS patients, 25 VS/UWS patients, and 30 healthy controls.
• Correlations between ReHo values and clinical scores (Coma Recovery Scale-Revised) were examined.

Main Results:

• MCS and VS/UWS patients exhibited reduced ReHo in posterior cingulate cortices, medial prefrontal cortices, and fronto-parieto-temporal regions, with increased ReHo in limbic areas.
• Reduced ReHo was observed in intrinsic connectivity networks (ICNs), including the default mode network (DMN), executive control network (ECN), and salience network (SN).
• A positive correlation between Coma Recovery Scale-Revised scores and reduced ReHo in the left precuneus was found in VS/UWS patients.

Conclusions:

• The study enhances understanding of regional connectivity mechanisms in DOC.
• Findings suggest ReHo analysis can serve as a neuroimaging biomarker for clinical diagnosis of MCS and VS/UWS.
• Altered ReHo patterns reflect the severity of consciousness impairment in DOC.