Transcranial direct current stimulation in patients with depression: An electric field modeling meta-analysis

Area of Science:

• Neuroscience
• Psychiatry
• Medical Engineering

Background:

• Transcranial Direct Current Stimulation (tDCS) shows promise for treating depression by modulating cortical activity.
• Inconsistent outcomes in tDCS depression treatment are linked to variable electrode montages and electric field strengths.
• Current meta-analyses often overlook the impact of montage and electric field distribution on treatment variability.

Purpose of the Study:

• To investigate the relationship between electric field distribution, montage parameters, and clinical outcomes in tDCS for depression.
• To identify specific brain regions and electric field intensities associated with positive tDCS response in depression.
• To address inter-experimental variability by incorporating anatomical differences in head models.

Main Methods:

• A meta-analysis correlating clinical outcomes (effect size) with electric field intensities.
• Utilized 8 diverse head models to simulate electric field distribution across 29 studies (1766 patients, 2000-2023).
• Analyzed data considering montage heterogeneity and individual anatomical variability.

Main Results:

• tDCS demonstrated a significant overall effect on depression (Hedge's g = 0.66).
• Contrary to the intended L-DLPFC (BA 46) targeting, electric fields showed broad frontal lobe distribution with significant heterogeneity.
• A correlation between electric field strength and clinical outcomes was found in BA 10, BA 11, and anterior BA 46.

Conclusions:

• Targeting frontopolar prefrontal cortex (BA 10, BA 11) and orbitofrontal cortex (anterior BA 46) may be more effective for tDCS in depression.
• Individual anatomical variability and precise electric field modeling are crucial for optimizing tDCS treatment.
• Highlights the need for simulation-guided, personalized tDCS trials for depression management.