This study will investigate whether transcranial direct current stimulation (tDCS) enhances the effects of computerized cognitive training in older adults with recurrent depression (2 or more lifetime episodes; either current or within past 3 years).
The purpose of this study is to determine whether the addition of active tDCS to computerized cognitive remediation (nCCR) enhances brain activity and cognitive functions in older adults with recurrent depression to a greater degree than nCCR with sham stimulation. The investigators will randomize 20 elderly depressed outpatients to either double-blinded active or sham bifrontal tDCS plus daily nCCR over 4-weeks. Multimodal MRI (focused on the cognitive control network; CCN) and psychiatric and neuropsychological evaluations will be obtained at baseline and following intervention completion. Long-term CCN cognitive effects will be explored 3-months post-intervention via cognitive assessments.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
16
Computerized cognitive training targeting the underlying cerebral networks associated with depression.
A Soterix Clinical Trials Direct Current Stimulator will apply 20 minutes of 2.0 milliamps (mA) direct current through two bicarbon rubber electrodes encased in saline soaked 5 cm x 7 cm sponges (8 cc of 0.9% saline solution per sponge) placed over the frontal cortices at F3 and F4 (via 10-20 system).
Sham stimulation will be performed with the same device and all procedures will be identical except for the duration of stimulation. Participants will receive 30 seconds of 2 mA of direct current stimulation at the beginning of the session. Participants habituate to the sensation of tDCS within 30-60 seconds of stimulation. This procedure provides the same sensation of tDCS without the full duration of stimulation, making it a highly effective sham procedure.
Vanderbilt University Medical Center
Nashville, Tennessee, United States
Change in task-based fMRI activation within the Cognitive Control Network during the n-back task
MRI scans will be performed at baseline and after completion of the intervention. MRI will measure Cognitive Control Network function, operationalized as change in n-back functional MRI response in the anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC), and the posterior parietal cortex (PPC) regions of interest. The n-back functional MRI response is calculated as the activation difference (beta values) between 2-back and 0-back conditions of the n-back over time (post treatment - baseline). Higher scores indicate more activation. We will then examine correlations between the fMRI activity and n-back behavioral performance measures (accuracy, response time).
Time frame: From baseline to post-intervention (4-6 weeks)
Change in n-back behavioral performance (accuracy and response time)
Target accuracy and response time data on the n-back will be extracted for each n-back condition (2-back and 0-back) and over time (baseline, post-intervention). Higher scores for the metrics indicate better accuracy but slower response time.
Time frame: From baseline to post-intervention (4-6 weeks)
Change in NIH Examiner scores
This cognitive test battery assesses a range of executive functions (working memory, inhibition, set shifting, fluency, insight, and planning). The investigators will examine its Executive Composite Score, with higher scores indicate better performance.
Time frame: From baseline to post-intervention (4-6 weeks)
Change in California Verbal Learning Test, 2nd edition (CVLT-2) scores
The CVLT-2 is a standardized measure of verbal learning and memory, with higher scores indicative of better learning and memory performances.
Time frame: From baseline to post-intervention (4-6 weeks)
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