To reduce chronic pain

Transcranial direct current stimulation (tDCS) is a non-invasive method that stimulates the brain with electrodes placed on the scalp. A low-intensity electric current moves from one electrode to the other to change brain activity. These treatments aim to reduce chronic pain.

Of the many types of electrodes, those used for tDCS are rubber electrodes inserted into a sponge. These electrodes must be moistened in a saline solution before they are placed on the scalp. The electrodes are held in place with a headband. 50% of the emitted current reaches brain tissue; the rest of the current is lost due to the skin and the skull.

Who should use tDCS?

The treatments aim to reduce chronic pain, but certain conditions respond better to this type of treatment:

• Musculo-skeletal injuries present for more than 6 months
• Post-stroke pain
• Chronic nerve pain

More recently, tDCS has been used for children with severe neurological problems such as cerebral paralysis, in order to improve the brain’s ability to acquire new neuromotor skills.

In practice

A tDCS session lasts for a little morethan 20 minutes and is repeated for 4-5 consecutive days. This anodic stimulation induces an increase in cortical excitation, which can last longer than the duration of the stimulation. Consequently, the reduction of pain is often perceived after 2 or 3 sessions, and its effects can last anywhere from a few weeks to several months.

Contraindications

First and foremost, patients must be evaluated in order to learn if tDCS applies to their condition. The following contraindications exist:

• the presence of severe or frequent migraines
• chronic skin problems
• the presence of metal plates on the head
• the use of any stimulators or implants
• the presence of epilepsy or the presence of serious or recent head trauma, because neurochemical changes may modify the flow of the current.