Objectives: To assess the effect of transcranial direct current stimulation versus no stimulation on working memory in elders with normal cognitive status
Design: a double blind randomized clinical trial.
Setting and conduct: The eligible elders who will refer to School of Public Health, Zahedan University of Medical Sciences, during the study period will be enrolled into the trial.
Inclusion criteria: (a) age above 60 years; (b) score of MMSE less than 25.
Exclusion criteria: (a) psychological disorders such as schizophrenia, mood disorder, dementia, active psychosis, and stimulant dependent; (b) neurological disorders involving central nerves system such as Alzheimer, Parkinson, stroke, multiple sclerosis; (c) chronic diseases such as diabetes, renal failure, lever failure, and hypo-thyroiditis; (d) history of head trauma during past six months.
Intervention group: Andean stimulate of the left prefrontal skull with amperage 2 mA for 20 minutes daily for 5 days.
Control group: Virtual stimulate of the left prefrontal skull for 20 minutes daily for 5 days.
Primary outcome: Assessing the working memory using n-back test before intervention, before the third stimulation, the day after completion of stimulation and 2 week after intervention; (b) Assessing the verbal working memory using Digit span test before intervention, before the third stimulation, the day after completion of stimulation and 2 week after intervention.
Secondary outcome: assessing cognitive impairment using MMSE questionnaire before intervention and 2 weeks after intervention.
Randomization: Random assignment of the patients to the intervention and control groups using drawing lots.
Blinding: Patients will be unaware of the type of stimulation. The examiner will not be aware of the stimulation. Therefore, the trial will be run as triple blind.