The Effects of Specific tDCS on Cognition in MCI

INTRODUCTION: Mild cognitive impairment (MCI) is a critical transitional stage in dementia related disorders. Dorsolateral prefrontal cortex (DLPFC), and the lateral parietal (LPC) cortex are subjected to neuropathological changes in MCI. Parietal memory network (PMN) integrity alterations and default mode network (DMN) alterations also occur in MCI. Transcranial direct current stimulation (tDCS) is a promising neuroprotective tool that modulates functional connectivity and might be useful to interfere with cognitive decline in relation to amnestic MCI (aMCI) and Parkinson's disease-MCI (PD-MCI) when applied to DLPFC and LPC. METHODS: This is a multicenter, randomized, and controlled study evaluating the effectiveness of anodal tDCS (atDCS ) applied bilaterally to the DLPFC/F3-F4 and LPC/ P3-P4 for 5 sessions with a total of 10 sessions in 14 days. The stimulation will be delivered with a 2 mA current frequency and will last 20 minutes a day for 5 days a week. The study consists of anodal, and sham control groups with a total of 120 participants with DLPFC and LPC anodal groups including 40 participants each and sham including 40 participants which are all between 45-80 years of age. At baseline and as an outcome measure, neurocognitive evaluation will be conducted using various tests standardized to use in the Turkish population. Functional magnetic resonance (fMRI) will be used to detect possible PMN and DMN alterations and hippocampal connectivity, and electroencephalogram (EEG) will be used to assess possible electrophysiological alterations that may happen as a result of atDCS. Baseline evaluation will be done before atDCS sessions and it will be repeated at the end of 14 days and 90 days. DISCUSSION: This study aims to explore the effectiveness of atDCS in PD-MCI, aMCI and to contribute to the literature in the field.