The goal of this project is to train currently major depressed patients on fundamental aspects of working memory while the investigators administer transcranial Direct Current Stimulation (tDCS) over the left dorsolateral prefrontal cortex (DLPFC) during these training sessions. This working memory training would be performed using adaptive Paced Auditory Serial Addition Tasks (PASAT). The effects after two weeks of working memory training combined with tDCS or sham placebo (10 sessions) will be measured on different variables, each measured at the start and at the end of the two weeks of training. The investigators expect the greatest anti depressant results and cognitive enhancements in the group of depressed patients that received tDCS combined with working memory training.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
40
This group will receive 2.0 mA anodal DC stimulation over the left DLPFC and cathodal stimulation over the right DLPFC. During the stimulation, this group will be trained on working memory processes. Sessions will be scheduled daily for two consecutive weeks.
This group will receive sham stimulation (e.g., identical stimulation set-up but no electric current is sent through the electrodes). Patients however receive the real working memory training, daily, for two weeks.
University of São Paulo, Hospital Universitário
São Paulo, São Paulo, Brazil
Universidade Presbiteriana Mackenzie
São Paulo, São Paulo, Brazil
Hamilton Depression Rating Scale
The primary outcome measure is the score of HDRS-24 scale after 4 weeks of treatment.
Time frame: 4 weeks
Beck Depression Inventory
The outcome measure is the score of BDI scale after 4 weeks of treatment.
Time frame: 4 weeks
follow-up measure
Two weeks after each participant finished his/her treatment, the investigators will contact them to verify whether treatment induces long-lasting effects. This contact will be established via email and we will ask them to fill in the same self report questionnaires as they filled in during the study protocol.
Time frame: after two weeks
Internal Shift Task
The Internal Shift Task (IST), an emotional attention paradigm, will be administered to measure the ability to switch attention between emotional and non emotional items in working memory. After 10 sessions of tDCS in combination with the working memory training, the investigators expect a transfer effect on an increased switching ability between emotional stimuli.
Time frame: 2 weeks
Working memory task in combination with pupil dilatation
This task will be administered to measure participants' ability to manipulate emotional information in working memory: either reverse or maintain in the order of three emotion or three neutral words. The investigators hypothesize that the pupil size will be decreased when sorting negative words in working memory in depressed patients that received active tDCS over the left DLPFC in combination with attentional training.
Time frame: 2 weeks
Heart Rate Variability
This measure will be utilized to evaluate autonomic activity by recording electrocardiogram or pulse wave. High HRV has been associated with greater behavioral adaptability and plays a major role in the adaptive recovery from stress. After the treatment, the investigators expect MDD patients that received tDCS with working memory training to demonstrate increased HRV while viewing negative high arousing IAPS pictures.
Time frame: 2 weeks
Salivary Cortisol
This measure will be utilized to evaluate endocrinological response of the hypothalamic-pituitary-adrenal(HPA)axis, such as cortisol secretion. After the treatment, the investigators expect MDD patients that received tDCS with working memory training to demonstrate decreased cortisol secretion while viewing negative high arousing IAPS pictures.
Time frame: 2 weeks
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