Frontal Transcranial Direct Current Stimulation in Moderate to Severe Depression: Clinical and Neurophysiological...

Area of Science:

• Neuroscience
• Psychiatry
• Medical Devices

Background:

• Transcranial Direct Current Stimulation (tDCS) shows promise for Major Depressive Disorder (MDD).
• Neurophysiological mechanisms of tDCS, particularly frontal electroencephalogram (EEG) markers, require further elucidation.
• Understanding these mechanisms is crucial for optimizing tDCS efficacy in depression treatment.

Purpose of the Study:

• To investigate the clinical effectiveness of frontal tDCS in individuals with mild to severe depression.
• To examine the neurophysiological impact of tDCS on EEG markers, including Frontal Alpha Asymmetry (FAA), Beta Symmetry, and Theta/Alpha Ratios.
• To correlate EEG changes with clinical improvements in depressive symptoms.

Main Methods:

• Thirty-one participants with depression underwent a 3-week frontal tDCS protocol (Flow Neuroscience, F3/F4 montage).
• Clinical outcomes were assessed using the Montgomery-Åsberg Depression Rating Scale (MADRS).
• Quantitative EEG (QEEG) was recorded pre- and post-treatment to evaluate neurophysiological changes.

Main Results:

• Significant MADRS score reductions were observed across all participants post-tDCS.
• Clinical response rates were higher in the moderate/severe depression group (71.4%) versus the mild group (20.0%).
• A significant reduction in the Theta/Alpha Ratio at F4 was noted in moderate to severe depression cases, correlating with clinical improvement.

Conclusions:

• Frontal tDCS demonstrates clinical efficacy in reducing depressive symptoms, particularly for moderate to severe MDD.
• While FAA and Beta Symmetry showed no significant changes, Theta/Alpha Ratio alterations at F4 suggest neurophysiological reorganization.
• The Theta/Alpha Ratio may serve as a potential biomarker for tDCS treatment response in depression.