[Influence of transcranial direct current stimulation on cognitive functioning of patients with brain injury].

Clinical consequences of brain injuries are not simply the result of the initial insult, but also reflect dynamic changes of activity in disrupted neural networks, some of which might be maladaptive. Transcranial direct current stimulation (tDCS), which delivers weak polarizing direct currents to the cortex, is used to modulate cortical excitability. The nature of neuromodulation depends on the stimulation polarity: anodal stimulation increases cortical excitability while cathodal stimulation reduces it. It has been demonstrated that tDCS-induced brain modulations are associated with cognitive changes. In most paradigms tested, excitability-enhancing anodal tDCS proved beneficial to learning and memory processes, attention, and linguistic skills. In this context, tDCS appears to be a promising method to improve cognitive functions in patients with various neurological disorders, including stroke and neurodegenerative diseases. Exposure to brain polarization may help in specific and selective enhancement of adaptive patterns of activity, suppression of non-adaptive activation patterns, and balancing interhemispheric interactions.