Cognitive Effects of Transcranial Direct Current Stimulation Plus Robotic Verticalization in Minimally Conscious State

Abstract

Background and objectives: Transcranial direct current stimulation (tDCS) is a non-invasive therapeutic method that modulates cortical excitability and shows promising results for treating disorders of consciousness (DoCs). Robotic verticalization training (RVT) has been shown to enhance motor and cognitive recovery. This study evaluates the effects of an innovative approach combining RVT with tDCS in individuals with DoCs.

Methods: Twenty-four subjects with DoCs, particularly those with chronic minimally conscious state (MCS) due to vascular or traumatic brain injury, participated in a quasi-randomized study at the Neurorehabilitation Unit, IRCCS Neurolesi (Messina, Italy). Participants were divided into either a control group (CG) receiving RVT alone or an experimental group (EG) receiving combined tDCS and RVT. Both groups underwent treatments five times weekly for four weeks, with tDCS/sham sessions over the dorsolateral prefrontal cortex (DLPFC) lasting 20 min before Erigo training sessions, which lasted 45 min.

Results: The findings indicate that combining tDCS with Erigo^® Pro RTT could lead to greater improvements in cognitive functioning and P300 latency compared to the CG.

Conclusions: These results suggest that the integrated approach of tDCS with RVT could offer significant benefits for patients with MCS, highlighting its potential to enhance cognitive recovery, such as reducing P300 latency.

Keywords: DoC; P300; disorders of consciousness; neurorehabilitation; robotic verticalization training; tDCS; transcranial direct current stimulation.

Figure 1

The image shows a RVT session in a patient with MCS using the Erigo^® device. The patient is positioned on the device, which provides controlled verticalization and passive mobilization of the lower limbs, facilitating both motor stimulation and safe upright positioning.

Figure 2

Change scores in P300 latency, LCF, and FIM between baseline (T0) and end of treatment (T1). Note. The figure shows changes in P300 latency (blue bars), level of consciousness (LCF; gray bars), and functional independence measure (FIM; light blue bars) between baseline (T0) and post-treatment (T1) for the experimental and control groups. Error bars represent standard deviations. Statistically significant improvements (p < 0.01) were observed in the experimental group across all measures, while the control group showed no significant changes. P300 latency was assessed using neurophysiological measures, while LCF and FIM scores were evaluated using clinical assessment tools. Paired t-tests were performed to analyze within-group differences from T0 to T1.