The aim of this study is to evaluate the oxidative stress and brain damage biomarkers induced by tDCS in patients with AD and to assess the long term neurophysiological and behavioral effects after repeated daily tDCS sessions for 10 days. Thirty AD patients diagnosed according to 2011 McKhann criteria will be randomly assigned to receive 10 real anodal tDCS or sham at 2mA intensity for 20 minutes per session daily. All patients will be evaluated at baseline, at the end of the sessions and 1, 2, and 3 months later with neurophysiological and behavioral examination.

The aim of this study is to evaluate the oxidative stress and brain damage biomarkers induced by tDCS in patients with AD and to assess the long term neurophysiological and behavioral effects after repeated daily tDCS sessions for 10 days. Thirty AD patients diagnosed according to 2011 McKhann criteria will be randomly assigned to receive 10 real anodal tDCS or sham at 2mA intensity for 20 minutes per session daily. Patients were classified into two groups using closed envelope. One group will receive 10 sessions real tdcs and other group will receive sham tdcs.

The study will be a double-blind, placebo controlled, within subject, parallel design.

tDCS will be delivered bilaterally by a constant current electrical stimulator connected to a pair of sponge electrodes. The investigators will use a non-cephalic reference electrode for tDCS: stimulating electrode will be placed over the left temporo-parietal lobe for 20 minutes and then over the right temporoparietal lobe for another 20 minutes in AD patients, while the reference electrode will be placed over the right deltoid muscle. The stimulating current will be anodal DC at 2 mA intensity delivered for 20 minutes per session for 10 days. All patients will be evaluated at baseline, at the end of the treatment and 1 and 2,and 3months later with neuropsychological and behavioural examination.

Inclusion Criteria:

• All subject were diagnosed with Probable AD according to NINCDS/ADRDA Criteria for Alzheimer's Disease.
• Onset age > 60.
• All 4 grandparents are of Ashkenazi Jewish origin as declared by the subject.
• Subject or subject's legal representative has signed the informed consent form.

Exclusion Criteria:

• All subjects who were diagnosed with Possible AD according to NINCDS/ADRDA Criteria for Alzheimer's Disease.
• Subjects who were diagnosed with dementia due to other diseases, or with AD and contribution of other disorders (Mixed dementia):
• Brain CT/MRI suggesting alternative diagnoses, such as intracranial space occupying lesions, vascular lesion of the brain, white matter lesion, or hydrocephalus.
• Subjects who had known carrier of a blood transmitted infectious disease or suffers from conditions in which phlebotomy is contra-indicated.