Efficacy of rTMS/tDCS in cognitive neurorehabilitation. Consensus paper

Cognitive deficits are a common consequence of neurologic disease, in particular, of traumatic brain
injury, stroke, and neurodegenerative disorders, and there is evidence that specific cognitive training
may be effective in cognitive rehabilitation. Several investigations emphasize the fact that interacting
with cortical activity, by means of cortical stimulation, can positively affect the short-term cognitive
performance and improve the rehabilitation potential of neurologic patients. In this respect, preliminary
evidence suggests that cortical stimulation may play a role in treating aphasia, unilateral neglect, and
other cognitive disorders. Several possible mechanisms can account for the effects of transcranial
magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) on cognitive performance.
They all reflect the potential of these methods to improve the subject’s ability to relearn or toacquire new strategies for carrying out behavioral tasks. The responsible mechanisms remain unclear
but they are most likely related to the activation of impeded pathways or inhibition of maladaptive
responses. Modifications of the brain activity may assist relearning by facilitating local activity or by
suppressing interfering activity from other brain areas. Notwithstanding the promise of these
preliminary findings, to date no systematic application of these methods to neurorehabilitation
research has been reported. Considering the potential benefit of these interventions, further studies
taking into consideration large patient populations, long treatment periods, or the combination of
different rehabilitation strategies are needed. Brain stimulation is indeed an exciting opportunity in the
field of cognitive neurorehabilitation, which is clearly in need of further research.