Prolonged visual memory enhancement after direct current stimulation in Alzheimer's disease

Paulo Sergio Boggio, Roberta Ferrucci, Francesca Mameli, Débora Martins, Oscar Martins, Maurizio Vergari, Laura Tadini, Elio Scarpini, Felipe Fregni, Alberto Priori

Research output: Contribution to journalArticle

Abstract

Background: Immediately after patients with Alzheimer's disease (AD) receive a single anodal transcranial direct current stimulation (tDCS) session their memory performance improves. Whether multiple tDCS sessions improve memory performance in the longer term remains unclear. Objective: In this study we aimed to assess memory changes after five consecutive sessions of anodal tDCS applied over the temporal cortex in patients with AD. Methods: A total of 15 patients were enrolled in two centers. Cognitive functions were evaluated before and after therapeutic tDCS. tDCS was delivered bilaterally through two scalp anodal electrodes placed over the temporal regions and a reference electrode over the right deltoid muscle. The stimulating current was set at 2 mA intensity and was delivered for 30 minutes per day for 5 consecutive days. Results: After patients received tDCS, their performance in a visual recognition memory test significantly improved. We found a main effect of tDCS on memory performance, i.e., anodal stimulation improved it by 8.99% from baseline, whereas sham stimulation decreased it by 2.62%. tDCS failed to influence differentially general cognitive performance measures or a visual attention measure. Conclusions: Our findings show that after patients with AD receive anodal tDCS over the temporal cerebral cortex in five consecutive daily sessions their visual recognition memory improves and the improvement persists for at least 4 weeks after therapy. These encouraging results provide additional support for continuing to investigate anodal tDCS as an adjuvant treatment for patients with AD.

Original languageEnglish
Pages (from-to)223-230
Number of pages8
JournalBrain Stimulation
Volume5
Issue number3
DOIs
Publication statusPublished - Jul 2012

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Keywords

  • Alzheimer's disease
  • brain polarization
  • memory
  • tDCS

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)
  • Biophysics

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