What is tDCS?

Transcranial Direct Current Stimulation or tDCS is a Non-Invasive Brain Stimulation technique in which a device sends a small Direct Current (DC) derived from a small 9V battery across the scalp to modulate brain function. Electrodes (sponges soaked in salt water) are placed over certain parts of the head. The electrodes are held in place using a headband. The direct current flows through the electrodes, penetrating the scalp, creating a flow of electrical current in the brain. Usually a slight itching or tingling sensation can be felt on the scalp in the first few seconds. The weak currents enhance brain activity under the site of the electrodes.

What are the indications for tDCS?

tDCS is considered to safely induce reversible changes in neuron excitation and can induce benefits in various conditions, such as:

1. Treatment of depression
2. Anxiety Disorders
3. Alzheimer’s disease
4. Fibromyalgia
5. Chronic neuropathic pain
6. Migraine
7. Chronic Headache
8. Parkinsonism
9. Post- Stroke recovery
10. Tinnitus (ringing in the ears)
11. Multiple Sclerosis
12. Enhancement of Learning
13. Enhancement of Cognitive Skills such as Attention and Memory
14. Enhancement of Language and Mathematical Ability

What are the effects of tDCS on the brain?

tDCS has a significant effect on neurological activity in the targeted parts of the brain. Each device has an Anodal electrode and a Cathodal electrode. The Anodal electrode is the positively charged electrode and the Cathodal electrode is the negatively charged electrode. The current flows from the cathodal electrode to the anodal electrode, creating a circuit. Thus, there are two types of stimulation with tDCS – Anodal and Cathodal stimulation. Anodal stimulation acts to excite neuronal activity while Cathodal stimulation inhibits or reduces neuronal activity. In other words, tDCS stimulation changes brain function either by causing the neuron resting membrane potential to depolarize or hyper polarize. When positive stimulation is delivered, the current causes a depolarization of the resting membrane potential, which increases excitability of brain cells and allows for more spontaneous cell firing. Negative stimulation causes a hyper polarization and decreases or inhibits neuron function.

One of the most important aspects of tDCS is its ability to achieve and cause sustained cortical (brain activity) changes even after the stimulation is ended. The duration of this change depends on the length of stimulation as well as the intensity of current.