Transcranial Random Noise Stimulation over the Dorsolateral Prefrontal Cortex in Patients with Parkinson’s Disease and Mild Cognitive Impairment: A Pilot Study

Background/Objectives: Mild cognitive impairment (MCI) is common in Parkinson’s disease (PD) and often precedes dementia. Non-invasive brain stimulation (NIBS) techniques such as transcranial random noise stimulation (tRNS) targeting dorsolateral prefrontal cortex (DLPFC) may offer additional benefits for cognitive and motor functions in PD-MCI patients. Methods: Using a randomized, double-blind, cross-over study, participants with PD-MCI completed two stimulation sessions (real vs. sham) 7 days apart. Cognitive and motor outcomes (MoCA, FAB, FAS, MDS-UPDRS motor) were assessed pre- and post-stimulation; stimulation was administered “online” during executive training. Scores before and after the sessions have been compared, as well as their variations between the two groups. Results: Ten subjects were in the study. Patients undergoing real tRNS showed improvements in global cognition and executive functioning compared to those undergoing sham stimulation, as demonstrated by significant increase in MoCA and FAB scores. In contrast, the motor examination showed no significant differences. Conclusions: This preliminary study showed that a single session of DLPFC-tRNS stimulation produced domain-specific cognitive benefits in PD-MCI patients. Studies with multiple stimulation sessions and larger samples are needed to confirm the effect of this non-pharmacological therapeutic option in PD-MCI.