Transcranial Direct Current Stimulation vs. Magnetic Stimulation

Understand the differences between transcranial direct current stimulation and magnetic stimulation in this detailed guide.

Transcranial direct current stimulation (tDCS) is a painless and non-invasive brain stimulation that relies on direct electrical currents to stimulate particular areas of your brain. This article takes a look at how this method works and how it compares to magnetic brain stimulation.

How Does tDCS Work?

A low intensity but constant current is sent through two electrodes that are set on your head to track neuronal patterns. There are two types of stimulants, cathodal and anodal stimulation. Anodal stimulation stimulates neuronal activity while cathodal reduces them.

One of its effects is inducing cortical changes even when the stimulation is over. However, the duration of this change depends on how intense the stimulation is and how long the session was. Generally, the longer and more intense the stimulation is the longer the cortical change and effect will be.

Using DC stimulation, changes are made to the resting membrane of a neuron, leading to hyperpolarization or depolarization. It is the anodal positive stimulation that leads to neuronal stimulation, causing the cells to fire and leading to improved brain activity.

Unlike other methods, direct current stimulation is still new and experimental, but it has already shown numerous advantages over other techniques as it is safe, painless, affordable and non-invasive. Administration is easy and it is also portable as well.

What are the Benefits?

TDCS has shown promise in the treatment of chronic pain, Parkinson’s disease, anxiety and depression as well as other neuropsychiatric conditions. Studies have also shown that the method enhances cognitive functions, though the technique has yet to receive FDA approval.

Aside from enhancing cognitive functions, direct stimulation can also improve one’s mood as well as increase concentration and focus. Trials conducted under double blind conditions suggest that those who undergo this stimulation are able to focus more on what they are doing, and there are cases wherein neuropathic pain was removed.

A study published in Medscape (Colleen K Loo; Donel M Martin) shows that DC stimulation leads to improvement in visual tracking, crucial when reading, and also provides relief from psychogenic stuttering. In all the tests the results also showed improvements in psychomotor speed. There’s also study ongoing to determine its effect on pain syndromes, with the latest research showing that it has therapeutic effects.

What are the Side Effects?

The most common side effect is tingling or itching on the scalp. In addition there are a few cases of dizziness, headache and nausea when using the electrodes. There are ways to overcome this however, such as preparing the electrodes with saline solution though in some cases this isn’t even necessary.

This stimulation should not be administered on individuals who have epilepsy or prone to seizures. Healthy people don’t have to worry about getting seizures however.

What is Magnetic Stimulation?

Transcranial magnetic stimulation (TMS)is another non-invasive method that stimulates your brain. Rather than use electrodes or electromagnetic induction, an insulated coil is positioned on the scalp. This is set on a specific area of the head and plays a major role in regulating moods.

The coil produces small magnetic pulses that pass through your head rapidly and without causing any pain. These pulses have the same strength as those used in MRI (magnetic resonance imaging), and when the pulses are produced quickly one after the other it becomes repetitive, and this produces longer lasting effects on the brain. These repetitive forms of magnetic stimulation is a generally safe procedure and tolerated well during trials and tests.

What are the Benefits?

TMS has been shown to be an effective form of treatment for people suffering from depression. For this reason this can be a safe, alternative method for those who don’t want to take antidepressants or when those drugs are no longer effective. This stimulant also doesn’t carry the side effects that most antidepressants have, which is another reason for its popularity. While this can be an effective treatment for depression, it’s not for everyone, and you have to undergo a series of tests to determine if it is right for you.

Aside from treating depression, magnetic brain stimulation can be used to measure the function and activity in your brain. There’s also evidence that it can be used to analyse the connection between a muscle and the primary motor cortex. With this knowledge it becomes possible to determine the amount of damage caused by injuries, motor neuron disease, movement disorders, and stroke.

There is also some evidence suggesting that this technique can be used to stimulate brain activity and improve memory, focus and concentration. Moreover, injuries and disorders affecting the spinal cord and cranial nerves can be analysed using this method.

What are the Side Effects?

Brain stimulation using magnetic stimulation is considered generally safe, but there are risks when the method is used for therapeutic rather than diagnostic purposes. The reason is when used for therapy, higher frequencies are required, and this can lead to some discomfort or pain.

In rare instances the stimulation leads to seizures and fainting, though the more common side effects are hypomania, temporary cognitive changes and temporary hearing loss. There are a few cases wherein people have experienced transient impairment of memory, but this is rare.

What is the Difference between the Two?

Both stimulate the brain, but while direct current simulation is just taking off, magnetic stimulants are already widely used. However they do share similarities such as increasing or decreasing neuronal activity, but the way this is induced varies. To be specific, stimulation by direct current is achieved using two unique directional currents that generate different effects. Magnetic stimulation on the other hand, relies on a higher frequency to induce repetition while a lower frequency reduces neuronal activity.

Both methods are safe and don’t cause any pain or discomfort. As of now however, magnetic stimulants are expensive and require the services of an expert coil holder. In contrast, transcranial direct current stimulation is easier to apply, and while the effect is smaller compared to magnetic stimulants, there is less chance of the individual suffering an adverse reaction.

How Can I Find Out More?

If you have more questions there are books and articles out there that go into much more detail.  If you have a specific question I can look into and add to this article please leave a comment below. This is an interesting area which can be delved into through further reading and research.