The Effects of tDCS on Depressive Symptoms,Neurocognitive Function and HRV in Unipolar Depression and Bipolar Depression

Tri-Service General Hospital

Status: Completed

Conditions: Depression, Bipolar; Electricity; Effects; Depressive Disorder, Major

Treatments: Device: tDCS over DLPFC

Study type: Interventional

Funder types: Other

Identifiers

NCT03287037

2-103-03-002-1

Details and patient eligibility

About

The study aimed to investigate whether transcranial direct current stimulation could improve depressive symptoms, neurocognitive function and modulate heart rate variability in unipolar and bipolar depression.

Full description

Background

Transcranial direct current stimulation encompasses the induction of a relatively weak constant current flow through the cerebral cortex via scalp electrodes . Dependent on stimulation polarity, this results in a modulation of cortical excitability and spontaneous neural activity. The technique was established in the 1950s and 1960s primarily in animals. In these early studies it was shown that subthreshold DC stimulation increases spontaneous neuronal activity if the anode is placed above or within the cortex, while exposure to cathodal polarity results in reduced activity. This is caused by a subthreshold membrane depolarization by anodal and a hyperpolarization by cathodal stimulation. It was demonstrated in humans that the after-effects of tDCS depend on modifications of NMDA receptor-efficacy. The after-effects of tDCS are blocked by the NMDA receptor antagonist dextromethorphan, and prolonged by the partial NMDA receptor-agonist D-cycloserine. This tDCS polarity-dependent alteration of NMDA receptor function seems to be initiated by the respective membrane potential shift and probably by the accompanying cortical activity modification,because it is prevented by the sodium channel blocker carbamazepine. Intraneuronal calcium concentration also contributes, because calcium channel antagonists eliminate the excitability-enhancing after-effects of anodal tDCS. Recently, tDCS has been reported to be a novel, non-invasive and safe therapeutic tool to treat neuropsychiatric disorders including depression. This therapeutic tool has been reported to show promising effect in treating unipolar and bipolar depression. However, the sample sizes have been small. Further work is needed to see if these early promising studies replicate. Much evidence has indicated that patients with depression show hypoactivity over left dorsolateral prefrontal cortex (DLPFC) and hyperactivity over right DLPFC. We therefore hypothesize that tDCS over DLPFC with anode placed at left DLPFC and cathode placed at right DLPFC would reduce depressive symptoms in patients with unipolar depression and bipolar depression.

The study aimed to investigate whether tDCS over DLPFC could modify depressive symptoms, neurocognitive function and heart rate variability of unipolar and bipolar depression.

Study design: open-label study.

Participants: 60 patients with unipolar depression and 60 with bipolar depression.

Others: see Arms and Interventions, Eligibility Criteria or Outcome Measures.

Enrollment: 82 patients

Sex: All

Ages: 20 to 65 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

Patients who met DSM-IV-TR criteria for major depressive disorder and bipolar depression and had moderate to severe depression severity (HAM-D score more than 17) were included in the study.

Exclusion criteria

1. pregnancy or breastfeeding.
2. having epilepsy, severe physical illness, any current psychiatric comorbidity or history of substance dependence.
3. having contraindications for transcranial electrical/magnetic stimulation.
4. having intracranial metal foreign bodies.
5. having a history of intracranial neoplasms or surgery, or a history of severe head injuries or cerebrovascular diseases.

Trial design

Primary purpose: Treatment

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

---

82 participants in 1 patient group

tDCS over DLPFC

Experimental group

Description:

Direct current (DC) generated by a DC stimulator (Eldith DC stimulator: www. neuroconn.de/dc-stimulator_plus_en/) was bilaterally delivered through a pair of saline-soaked surface sponge electrodes (35 cm2). The anodal electrode was placed over the left dorsolateral prefrontal cortex (F3, International EEG System 10-20) and cathode electrode over F4. Stimulation was applied at an intensity of 2 mA for 20 min, twice-daily on 5 consecutive weekdays. The twice daily sessions were separated by at least 3 hours.

Treatment:

Device: tDCS over DLPFC