Effects of tDCS-enhanced Cognitive Control Training on Depression

University Hospital Tuebingen

Status: Unknown

Conditions: Depression Unipolar

Treatments: Behavioral: Cognitive control training; Other: 2mA tDCS; Other: 1mA tDCS

Study type: Interventional

Funder types: Other

Identifiers

NCT03518749

01EE1403D-2

Details and patient eligibility

About

Deficient cognitive control (CC) is one of the central characteristics of major depression (MD). Hypoactivation of the dorsolateral prefrontal cortex (dlPFC) has been linked with this deficit. Antidepressants and cognitive-behavioral therapies modify CC most-likely as a common mechanism of treatment. Transcranial direct current stimulation (tDCS) is a safe, simple and effective non-invasive method to modulate the cortical excitability. It has been shown, that the activity of the dlPFC can be modulated by transcranial direct current stimulation (tDCS) with polarity-dependent learning-phase specific effects on performance that, when combined with training, can outlast the stimulation.

The goal of this randomized, sham-controlled, rater blind clinical trial is to investigate the effect of a tDCS-enhanced CC Training (CCT) on depressive symptom severity and compare the stimulation intensities 1mA, 2mA and sham tDCS. Overall, the study will include 57 participants (n = 19 per group). Each participant will complete 12 training sessions with online sham/ anodal tDCS.

As a training task we will use an adaptive version of the paced auditory serial addition task (PASAT). In the PASAT, digits are presented auditive and participants have to add the current digit to the digit they heard before. In the adaptive version the interstimulus-intervals decrease (increase) when four consecutive trials are correct (incorrect). The PASAT is known to elicit frustration. Participants have to exert cognitive control over these emotions to complete the task successfully.

Before, during and after the training symptom severity will be assessed. Baseline and post-training performance in the PASAT and in a transfer task (delayed working memory task, DWM) will be measured.

To further explore variables that influence the effect of tDCS on depressive symptom severity we will measure brain activity (EEG, NIRS), heart rate, global functioning (GAF), emotion regulation strategies, self-esteem, mood ratings and subjective performance ratings before and after the training and collect genetic factors.

Sustainability of the training effects will be measured at a follow-up visit (3 months later).

Enrollment: 57 estimated patients

Sex: All

Ages: 18 to 65 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• current Major Depressive Episode
• right handedness

Exclusion criteria

• history of seizures
• Intracranial implants (e.g. aneurysm clips, shunts, stimulators, cochlear implants, or electrodes) or any other metal object within or near the head, excluding the mouth, that cannot be safely removed
• pregnancy
• use of mood stabilizers
• diagnosed bipolar disorder
• current substance abuse (nicotine excluded)
• current substance addiction (nicotine excluded)
• diagnosed psychotic diseases
• diagnosed anorexia nervosa
• diagnosed personality disorders: cluster A, antisocial personality disorder,
• borderline personality disorder

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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57 participants in 3 patient groups, including a placebo group

1mA anodal tDCS + cognitive control training

Active Comparator group

Description:

1 mA anodal tDCS will be administered to the left dlPFC (F3) for 23 mins during the performance of a cognitive control training.

Treatment:

Other: 1mA tDCS

Behavioral: Cognitive control training

2mA tDCS + cognitive control training

Active Comparator group

Description:

2 mA anodal tDCS will be administered to the left dlPFC (F3) for 23 mins during the performance of a cognitive control training.

Treatment:

Other: 2mA tDCS

Behavioral: Cognitive control training

sham tDCS + cognitive control training

Placebo Comparator group

Description:

Sham tDCS (30 secs of tDCS) will be administered to the left dlPFC (F3) with 2mA at the beginning of a cognitive control training.

Treatment:

Behavioral: Cognitive control training