Functional networks in prolonged disorders of consciousness

Abstract

Prolonged disorders of consciousness (DoC) are characterized by extended disruptions of brain activities that sustain wakefulness and awareness and are caused by various etiologies. During the past decades, neuroimaging has been a practical method of investigation in basic and clinical research to identify how brain properties interact in different levels of consciousness. Resting-state functional connectivity within and between canonical cortical networks correlates with consciousness by a calculation of the associated temporal blood oxygen level-dependent (BOLD) signal process during functional MRI (fMRI) and reveals the brain function of patients with prolonged DoC. There are certain brain networks including the default mode, dorsal attention, executive control, salience, auditory, visual, and sensorimotor networks that have been reported to be altered in low-level states of consciousness under either pathological or physiological states. Analysis of brain network connections based on functional imaging contributes to more accurate judgments of consciousness level and prognosis at the brain level. In this review, neurobehavioral evaluation of prolonged DoC and the functional connectivity within brain networks based on resting-state fMRI were reviewed to provide reference values for clinical diagnosis and prognostic evaluation.

Temporal and spatial variability of dynamic microstate brain network in disorders of consciousness

“…These findings are consistent with previous observations of behavioral signs of visual awareness in VS patients 53,54 . In addition, according to the regulatory function, the brain network could be divided into high‐order networks (Salience network, SN, Dorsal attention network, DAN, Default mode network, DMN) and low‐order networks related to perceptual processing (auditory network, AN, visual network, VN) 55 . Primary visual cortex (BA 18,19) was significantly activated in tracking visual motion patterns, 52 gestural finger differentiation, sustained attention to color or shape, and horizontal sweep eye movements.…”

“… 53 , 54 In addition, according to the regulatory function, the brain network could be divided into high‐order networks (Salience network, SN, Dorsal attention network, DAN, Default mode network, DMN) and low‐order networks related to perceptual processing (auditory network, AN, visual network, VN). 55 Primary visual cortex (BA 18,19) was significantly activated in tracking visual motion patterns, 52 gestural finger differentiation, sustained attention to color or shape, and horizontal sweep eye movements. The BA 6L–BA 18M and BA 10L–BA 19R connections may have reflected that recursive processing from higher‐order cortex to lower‐order visual cortex in microstate B associated with the visual network plays a key role in distinguishing the two groups of patients.…”

Transcranial direct current stimulation modulates primate brain dynamics across states of consciousness.

“…From another clinical perspective, our results showing that 2 mA anodal PFC tDCS can positively influence the dynamic signatures of consciousness during anesthesia, are also consistent with the beneficial effects of such stimulation reported in DOCs patients (e.g., (Thibaut et al 2014; Angelakis et al 2014)). For instance, recent meta-analyses have concluded that tDCS is more effective in improving the level of consciousness in patients with a minimally conscious state (MCS) than in those with an unresponsive wakefulness syndrome (UWS), which is a more severe form of this medical condition (Xu et al 2022; Liu et al 2023). Our results support the efficacy of tDCS in improving consciousness markers in patients with DOCs, particularly in the least severely affected patients, and encourage the design of new clinical trials to investigate the effects of higher stimulation intensities.…”

Combining HD-tDCS with music stimulation for patients with prolonged disorders of consciousness: Study protocol for an RCT trial

“…Patients with DOC often have severe motor impairments and limited communication abilities, making the management of their condition particularly difficult (Lin et al, 2015). Prolonged disorders of consciousness (pDOC) refer to impaired consciousness lasting for more than 28 days (Li et al, 2023). Current treatment options for pDOC are limited (Giacino et al, 2018), and there is a need for effective interventions that can improve arousal without relying on active patient participation (Thibaut et al, 2019).…”