What is tDCS

During a treatment session, electrodes (sponges soaked in salt water) are placed over certain parts of the head.

Rubber straps keep the electrodes in place. A tDCS stimulator sends a small electric DC current through the electrodes, creating a flow of electrical current in the brain. Usually a slight itching or tingling sensation can be felt on the scalp. The weak currents enhance brain activity under the site of the electrodes.

tDCS differs from other brain stimulation techniques such as transcranial electrical stimulation (TES) and transcranial magnetic stimulation (TMS), by not inducing neuronal action potentials. This contributes to the safety of tDCS.

tDCS is an established, non-invasive and well tolerated technique with a vast body of research that spans more than two decades and counts more than 1100 peer-reviewed studies and clinical trials.

Effects of tDCS on the brain

One of the most important aspects of tDCS is its ability to achieve 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. Studies have shown that about 50% of the current reaches the brain.

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 neuronal excitability and allows for more spontaneous cell firing. Negative stimulation causes a hyper polarization and decreases neuron excitability.

On the right is a BOLD MRI study (blood oxygen level) on changes, associated with tDCS, in neurological activity in the supplementary motor cortex (M1). The left column shows neurological activity during voluntary finger tapping. The right column shows a significant increase in neurological activity during finger tapping, after anodal (+) stimulation with tDCS. tDCS can increase neuronal firing rates by up to 40%, while only affecting neurons that are already active.

Applications of tDCS

tDCS has therapeutic potential in patients with:
  • Alzheimer’s disease
  • Depression
  • Fibromyalgia (chronic neuropathic pain)
  • Migraine
  • Parkinsonism
  • Post stroke motor recovery
  • Tinnitus (ringing in the ears)
  • Traumatic spinal cord injury
  • and other illnesses

New applications are constantly discovered, as well as applications to enhance cognitive skills and influence learning and memory.

Continue to “Who should use tDCS”


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