The Intrinsic Network Dynamics Related to Abnormal Delta Rhythm in Consciousness Disorders (Short Review)

Aim: to explore the pathophysiological mechanisms and clinical significance of delta rhythms (≤4 Hz) in disorders of consciousness (DOC), including coma, unresponsive wakefulness syndrome (UWS), and minimally conscious state (MCS), as biomarkers for diagnosis, prognosis, and therapeutic targeting. Materials and Methods. A narrative review was conducted, focusing on experimental and clinical findings related to delta rhythm generation and modulation in the disorder of consciousness (DOC). Emphasis was placed on thalamo-cortical interactions, cortical inhibition, neuromodulatory deficits, and the role of glial cells, neuroinflammation, and metabolic disruptions. Quantitative EEG analysis and advanced neuroimaging were highlighted as key tools for assessing delta activity. Results. Delta rhythms were found to dominate EEGs across DOC states, with high-amplitude global activity in coma and low-amplitude activity in UWS, indicating cortical suppression and thalamocortical disconnection, respectively. In MCS, reduced delta power and improved connectivity correlated with intermittent purposeful behavior. Therapeutic interventions, including TMS, tACS, and pharmacological agents, showed potential for modulating delta rhythms. Additionally, stochastic resonance emerged as a novel mechanism to stabilize neural networks through noise. Conclusion. Delta rhythms serve as crucial biomarkers in DOC, offering diagnostic, prognostic, and therapeutic value. Multimodal approaches that integrate EEG, neuroimaging, and mechanistic studies are essential for deepening understanding and improving clinical outcomes in DOC management.