Noninvasive Brain Stimulation in Mild Cognitive Impairment and Dementia

This is a pilot study being done to attempt to improve verbal episodic memory in persons with mild cognitive impairment (MCI) and dementia. Although the hippocampus is a brain structure most often associated with early deficits in MCI and dementia, the pre-supplemental motor area (preSMA) and dorsal anterior cingulate cortex (DACC) have been shown to play a role in verbal episodic memory for such patients. The purpose of this study is to examine the efficacy of high-definition transcranial direct current stimulation (HD-tDCS) to the preSMA/DACC region and its influence on verbal episodic memory in patients with MCI and dementia. Entraining the preSMA/DACC circuit with 10 sessions at one of two levels of HD-tDCS will allow the researchers to investigate whether neuromodulation may be used to improve verbal episodic memory. Participants will receive 10 sessions at one of two levels of active stimulation (1 mA or 2 mA anodal HD-tDCS targeting preSMA/DACC for 20 min) or sham across 2 weeks. The device is used to deliver high definition transcranial direct current stimulation to targeted regions. A verbal episodic memory task will be completed at baseline, immediately following the last HD-tDCS session, and a 2-month follow-up. The investigators plan to recruit English-speaking participants aged 50 years and older with MCI and dementia. Participants will be randomized into HD-tDCS conditions.