Effect of single‐session transcranial direct current stimulation on cognition in Parkinson's disease

Aims Nonmotor symptoms (NMS) such as cognitive impairment and impulse‐control disorders in Parkinson's disease (PD) remain a therapeutic challenge. Transcranial direct current stimulation (tDCS) has emerged as a promising alternative, although its immediate effects on NMS have been less well defined. In this randomized, sham‐controlled, crossover study, we aimed to explore the single‐session tDCS effects on cognitive performance in PD. Methods Ten nondemented patients with PD completed two sessions in counterbalanced order, receiving 20 minutes of either 2 mA anodal or sham tDCS over the left dorsolateral prefrontal cortex (DLPFC). During stimulation, they performed the visual working memory and go/no‐go tasks. Performance of the tasks was compared between the two conditions. Results Single‐session anodal tDCS over the left DLPFC did not significantly improve cognitive tasks in PD compared with sham (P > .05). Conclusion Single‐session tDCS is ineffective in improving visual working memory and inhibitory control in PD. Further research may worth exploring alternative tDCS parameters, ideally with repeated sessions and concomitant training.