Improvement of Response to Cueing after Left Prefrontal Transcranial Direct Current Stimulation in Alzheimers disease

Background Several studies have reported the potential benefits of transcranial Direct Current Stimulation (tDCS) to improve memory performance in patients with neuropsychiatric disorders. In Alzheimer’s disease (AD), memory profile is characterized by a core deficit in ability to benefit of the cueing. So far, only a few authors showed improvement in recognition memory task after anodal tDCS over different brain regions. Methods and findings In a double-blind design, we assessed the effect of 10 anodal tDCS sessions over the left dorsolateral prefrontal cortex on verbal cued recall in a 69-year-old patient with probable AD. This man underwent one active stimulation (30 min of 2 mA anodal tDCS, twice a day, for 5 consecutive days) 3 weeks after receiving one sham stimulation (30 min of 0 mA anodal tDCS, twice a day, for 5 consecutive days). After active tDCS, our results showed improved Index of Sensitivity to Cueing (ISC) by 35% and 33%, for both total and delayed recall, respectively, compared to a 1.5% decrease and an increase of only 9% with sham tDCS. In addition, active tDCS resulted in a decrease of 67% in the number of intrusions compared to an increase of 8% for sham tDCS. The treatment was well tolerated and no serious side-effects were reported at any time. Conclusions These results suggest that tDCS could be used as a safety adjunctive therapeutic tool in AD. Keywords Alzheimer’s