Poster Presentation: Transcranial Direct Current Stimulation (tDCS) : An Overview

Introduction: The evolution of electrical stimulation of brain as a treatment modality began with discovery of electrical properties of Catfish by Egyptians. The birth of DC generator in 1(st) century and study of its effects on neuronal excitability by Priori in 1998 led to the development of modern tDCS, a non-invasive, cost-effective neuromodulation technique. tDCS which is one of the transcranial stimulation methods among others (tACS, tPCS, tRNS, sotDCS) have shown therapeutic utility in schizophrenia, mood and anxiety/child psychiatric/substance use disorders, cognitive enhancement and pain management. Mechanism of action: tDCS causes polarization of RMP through two electrodes placed on scalp; anode with excitability-enhancing; and cathode with inhibitory-enhancing effects. Recent studies show that it reduces level of biomarkers implicated in various neuropsychiatric disorders, causing symptomatic improvement. Electrode Placement: Electrode positioning is made through precise measurements using the International 10–20 System of Electrode Placement. The DLPFC (F3/F4) is the most common site targeted effectively in depression, schizophrenia and substance use disorders and rATL is targeted in Insight and problem-solving. Parameters of Stimulation: The usual electrode sizes are of 25–35 cm(2) with currents of 1–2 mA applied for up to 20–40 minutes. The 2.0 mA current for 5-30 minutes is the optimal therapeutic dose preferred in most studies. Safety and Tolerability of Procedure: The usual side effects are mild pain/itching/tingling, redness, insomnia and headache, which are transient and largely tolerable, and has proven to be in overall a safe procedure.