P 234. Transcranial direct current stimulation and Alzheimer’s disease

Abstract

Objective This study was done to compare the effect of anodal, cathodal or sham transcranial direct current stimulation (tDCS) applied over the left dorsolateral prefrontal cortex (DLPFC) on cognitive function in patients with Alzheimer disease (AD). Material and methods 34 AD patients with mild to moderate disease were randomly classified into three groups. The first group received anodal tDCS and 2nd group received cathodal tDCS and the 3rd group received sham tDCS stimulation over the left DLPFC, daily for 10 days (2 mA for 25 min every weekday for 2 weeks). Minimental State Examination (MMSE) and the verbal and performance scores of the Wechsler Adult Intelligent Scale (WAIS) were assessed before, after the 10 sessions, and then after 1, and 2 months later. Results There were no significant differences between groups in any of the demographic, clinical data or the rating scales at baseline. A two factor ANOVA with GROUP (anodal, cathodal, sham) and TIME (before, after, 1, 2 months) as main factors showed a significant GROUP × TIME interaction for the MMSE (df = 3,2, F = 3.2, p = 0.02) and a borderline significant effect for performance IQ (df = 3,2, F = XX, p = 0.044) but not verbal IQ. Post hoc paired comparisons of the groups showed that both anodal and cathodal TDCS improved MMSE by approx. 3 points versus sham. Only cathodal TDCS improved the performance IQ (by approx. 4 points). Conclusion These results suggest that 10 daily sessions of either cathodal or anodal tDCS over the DLPFC can produce a sustained improvement in MMSE for at least 2 months in AD. There was a small effect of cathodal TDCS on performance IQ.