Therapeutic interventions in patients with prolonged disorders of consciousness

Abstract

The management of patients with severe brain injuries and prolonged disorders of consciousness (DOC) raises important issues particularly with respect to their therapeutic options. The lack of treatment is challenged by new clinical and neuroimaging data indicating that some patients with prolonged DOC may benefit from therapeutic interventions, even years after the injury. The majority of the studies aiming at improving patients' level of consciousness and functional recovery includes behavioural and brain imaging open-label trials and case-reports, but several randomized clinical trials (RCT) have been conducted, especially using non-invasive brain stimulation. Only a couple of RCTs focused on the effects of drugs or sensory stimulation approaches, and only two Class II studies, on amantadine and transcranial direct current stimulation, have been published. While new therapeutic approaches seem to be valuable for patients with prolonged DOC, optimized stimulation parameters, alternative drugs or rehabilitation strategies still need to be tested and validated.

Exploring the neural, behavioural, and clinical effects of transcranial direct current stimulation in patients with a Prolonged Disorder of Consciousness; protocol for a double-blind randomised crossover feasibility study

“…It is worth noting that there are 16 published studies of tDCS with similar parameters to those in our study, totalling over 200 PDOC patients and no adverse effects reported [45]. In a recent study,…”

Network Mapping of Connectivity Alterations in Disorder of Consciousness: Towards Targeted Neuromodulation

“…Non-pharmacological interventions (reviewed in [26]) are divided into invasive (deep brain stimulation or vagal nerve stimulation) and non-invasive approaches (e.g., transcranial direct current stimulation-tDCS, repetitive transcranial magnetic stimulation-rTMS, transcutaneous auricular vagal nerve stimulation, low intensity focused ultrasound pulse and sensory stimulation program). Recent literature reviews [27,28] support the hypothesis that non-invasive brain stimulation (NIBS) is more successful than other therapies, but, considering the few studies available to date, these techniques are not yet officially recommended by clinical consensus groups. In particular, the dorsolateral prefrontal cortex (dlPFC) was identified as a better target for tDCS compared to the precuneus and motor cortex, due to its involvement in the cortico-subcortical network and to its strong connection with the thalamus and striatum, which are impaired in DoC according to the mesocircuit fronto-parietal model [29].…”

“…In particular, the dorsolateral prefrontal cortex (dlPFC) was identified as a better target for tDCS compared to the precuneus and motor cortex, due to its involvement in the cortico-subcortical network and to its strong connection with the thalamus and striatum, which are impaired in DoC according to the mesocircuit fronto-parietal model [29]. However, only two studies on tDCS provided class II evidence [28] and only in MCS patients, whereas for VS patients none of these approaches have provided group-level effects yet [30,31].…”

Effects of transcranial direct current stimulation on patients with disorders of consciousness after traumatic brain injury: study protocol for a randomized, double-blind controlled trial

“…It has also been shown that tDCS stimulation of the F3 position using the EEG 10/20 system can increase the blood flow perfusion in the DLPFC and decrease the function of bilateral thalamic blood flow, suggesting that tDCS may be involved in regulating the functional connection between the DLPFC and the thalamus. Thibaut et al [51] found that when tDCS is used to stimulate the dorsolateral left prefrontal lobe, the left DLPFC, thalamus and anterior wedge lobe increased in the tDCS-positive subjects. This may be a mechanism to improve the awareness of tDCS disturbances.…”