Transcranial direct current stimulation combined with cognitive training for the treatment of Parkinson Disease: a randomized, placebo-controlled study

Background: A number of non-motor symptoms occurs in Parkinson Disease (PD), cognitive decline and mood disturbances representing the most prevalent. Recent studies reported that cognitive training could potentially help to attenuate cognitive deficits in patients with PD and several researches demonstrated a beneficial effect of active transcranial Direct Current Stimulation (tDCS) over the left dorsolateral prefrontal cortex (anode over left dorsolateral prefrontal cortex, cathode over right supraorbital area) on cognitive deficits and mood disturbances. Objective: To investigate the effects of active tDCS combined with computerized cognitive training on cognition and mood disturbances in PD patients. Methods: Twenty-two patients with PD were assigned to either active tDCS plus computerized cognitive training (CCT) or sham tDCS plus CCT groups. Each patient underwent two weeks’ treatment of daily application of tDCS for 25 minutes during CCT focalized on functions related with prefrontal cortex. Each patient was evaluated at baseline, after treatment and at 3-month follow-up. Results: A significant reduction of depressive symptoms was observed in the active tDCS group from baseline to post-treatment assessment and from baseline to 3-month follow-up. An improvement in cognitive performances, referring more specifically to language, attentional and executive functions, was observed in both groups post-treatment and at follow-up. However, phonemic verbal fluency showed significant greater changes from baseline in the active tDCS group. Conclusions: We concluded that cognitive training along with active tDCS is a useful combined approach in the management of mood and cognitive dysfunctions in PD.