Bilateral M1 anodal transcranial direct current stimulation in post traumatic chronic minimally conscious state: a pilot EEG-tDCS study.

OBJECTIVE: We tested the preliminary effects of bilateral anodal transcranial direct current stimulation (tDCS) in patients with disorders of consciousness. DESIGN: Open label pilot study. SUBJECTS: Ten chronic (greater than 12 months) patients in a minimally conscious state (MCS) following severe traumatic brain injury. METHODS: The patients received 10 sessions of bilateral M1 anodal tDCS. Behavioural changes were assessed with the Coma Recovery Scale-Revised (CRS-R) before stimulation (T-1, T0), after five sessions (T1), at the end of the stimulation (T2), after two weeks (T3) and after three months (T4). Moreover, an EEG assessment was conducted. RESULTS: Eight out of 10 patients showed new clinical signs of consciousness; specifically, a 2-point CRS-R improvement was detected in the last follow-up (p = 0.004). EEG upper α bandwidth was greater in the parietal site at T1 (p < 0.034). In addition, we found a significant correlation between behavioral and EEG indices at T1 (r =  0.89; p =  0.001). CONCLUSION: This preliminary study presents several limitations (small sample size and no control group). However, it provides important initial data that can be used to design randomized clinical trials testing this novel approach in MCS and to further explore EEG as a neural marker for the effects of tDCS.

Anti-Inflammatory and Cortical Responses after Transcranial Direct Current Stimulation in Disorders of Consciousness: An Exploratory Study.

Disorders of consciousness (DoC) due to severe traumatic brain injury (TBI) are associated with severe disability and an alteration of cortical activation, angiogenesis, and inflammation, which are crucial elements for behavioural recovery. This exploratory study aimed to evaluate anti-inflammatory and cortical responses after transcranial direct current stimulation (tDCS) in traumatic prolonged disorders of consciousness. Ten minimally conscious state (MCS) patients underwent ten sessions of anodal tDCS (five sessions/week, two weeks, 40 min/session) on the primary motor cortex bilaterally. Clinical evaluations were performed using the Coma Recovery Scale-Revised (CRS-R) pre- and post-treatment. In contrast, after single and multiple tDCS sessions, the haemodynamic cortical response was obtained with functional near-infrared spectroscopy (fNIRS). Moreover, angiogenesis (angiopoietin-2, BMP9, endoglin, HbEFG, HGF, IL8, Leptin, PLGF, VEGF-A, and VEGF-C) and inflammation (GM-CSF, IFNg, IP10, MCP1, and TNFα) circulating biomarkers were collected. A significant haemodynamic response was observed after a single tDCS session, with an increased activation from 4.4 (3.1-6.1) to 7.6 (2.9-15.7) a.u. (p = 0.035). After ten tDCS sessions, a significant reduction of angiopoietin-2, VEGF-C, and IP-10 was detected. Moreover, a correlation between behavioural (CRS-R), TNFα (r = 0.89; p = 0.007), and IP10 (r = 0.81; p = 0.014) variation was found. In conclusion, a single tDCS session can increase the cortical activation in MCS patients. Moreover, multiple tDCS sessions showed an anti-inflammatory effect related to behavioural improvement.