Dementia with Lewy Bodies (DLB), this second most common form of degenerative dementia, presents more functional disability, more potentially fatal complication, more impaired quality of life than Alzheimer’s dementia. There is no FDA-proved medication can slow, stop or improve the progression of cognitive declines in DLB. Identifying effective treatments is a critical issue for DLB. In neuropathology, extracelluar α-syn oligomers interfere with the expression of long-term potentiation, and influence memory and learning. Transcranial direct current stimulation (tDCS) has been proposed to affect long-term synaptic plasticity through LTP and LTD, thereby improving cognitive ability. So far, only two researches assess the effect of tDCS in DLB. In this pilot study, we investigate the effects of tDCS in DLB.

Using a double-blind, randomized, sham- controlled and crossover trial design, 11 DLB aged 55-90 years (mean age 77.8) were included in the study. DLB diagnostics is according to DSM-5 criteria. The CDR ratings of DLB participants ranged from 0.5 to 2. The active tDCS (or sham) process includes consecutive daily sessions of active tDCS (or sham) for 10 days. The anodal electrode was over the left dorsal lateral prefrontal cortex (DLPFC) and the cathodal electrode on the right supraorbital area. In each session, we applied a current intensity of 2 mA and an electrode size of 25 cm2 for 30 min in the active group. All subjects received a series of neuropsychological tests, which included CDR, MMSE, CASI, NPI and WCST, before and after these treatment sessions. Chi-square tests, Wilcoxon signed rank tests and Mann-Whitney U tests were used to assess the differences in participant demographic characteristics and to compare the differences among groups.

On CASI, MMSE, NPI and WCST, there were no statistically significant differences between pre- and post the 10-session course for the active and the sham groups. No side effects reported during or immediately after active tDCS stimulation.

These results suggest that left DLPFC anodal, and right deltoid cathodal tDCS, do not improve cognition, behavioral and psychological symptoms in DLB. Larger-scale trials are needed to confirm the effect of tDCS in DLB.