What is transcranial electrical stimulation?

One of the newest forms of therapy takes advantage of electromagnetic forces for the treatment of neuropsychiatric disorders, offering advantages that other forms cannot achieve. Through transcranial electrical stimulation (TSE) of the brain it is possible to cause changes that help to modify it and facilitate the therapeutic process.

Let's see what we mean when we refer to transcranial electrical stimulation, what advantages it offers and in what possible areas this modern form of treatment could have a role.

What is transcranial electrical stimulation?

It is a procedure that, through very low electrical currents, manages to stimulate certain specific parts of the body. brain. As its name suggests, the procedure is transcranial, that is, the currents are applied outside the skull without the need to touch the patient. Contrary to what happens with most direct brain stimulation procedures where It is necessary to open the patient and the skull of her, transcranial electrical stimulation is a technique not invasive. Because of this and because it is completely painless, it is a very promising and safe line of research.

The technique works as follows: through a pair of electrodes placed on the skull, a very weak electrical current is applied directly to the brain for a few minutes. With these currents an electric field is generated that modulates the neural activity. As we know, the activation or not of neurons has to do with their depolarization, an electrical process that can be modified. In addition, the type of current used in stimulation will have particular effects.

For example, it is known that through transcranial electrical stimulation with direct current neurons alter their discharge rate. Depending on whether it is cathodic or anodic, the effects produce an increase or decrease in it. These changes can last from minutes to hours after stimulation, depending on the stimulation parameters. What is certain is that stimulation through direct current is capable of changing the performance of individuals in a wide range of cognitive tasks.

Another form of transcranial electrical stimulation uses alternating current at random frequencies. There are studies that find that the motor cortex, after being exposed for ten minutes to this type of current, becomes much more excitable. Thus, the neurons in this area subjected to electrical current are easier to activate and respond better to motor tasks. Similar effects have been found in different areas of the brain, highlighting the potential applications to induce brain plasticity and facilitate the rehabilitation of damaged areas or dysfunctional.

Advantages and disadvantages of this technique

Any therapeutic technique has its pros and cons. The ideal when we develop a technique, based on psychological or neurological principles, is to obtain the maximum benefit while minimizing the costs and negative effects.

Although this technique is still in its infancy and it is too early to finally talk about its advantages and disadvantages, it is possible to make a first sketch.

Advantage

The main positive aspect of transcranial electrical stimulation is that it is painless and non-invasive. It is a unique procedure in the sense that it acts directly on neuronal function, unlike the pharmacological interventions that must perform a series of steps before reaching the brain, without the need to open or enter nothing.

This opens up a whole range of therapeutic possibilities that could not be used using traditional techniques. For example, frail older patients who do not tolerate medication well and fail to get the full benefit they should from cognitive rehabilitation may find in transcranial electrical stimulation, an ideal complement to help re-stimulate those areas of the brain that are deteriorating without risking their Health.

The development of the technique also has very important theoretical implications for the neurosciences. Transcranial electrical stimulation induces a kind of brain plasticity artificial, allowing researchers to manipulate this variable and experimental, within the ethical, with it. Thus, research in this line has a parallel development to research on neuronal plasticity, the cornerstone of cognitive rehabilitation.

Drawbacks

More than inconveniences, it would be more appropriate to speak of obstacles or difficulties. The truth is that it is a recently developed procedure that does not yet have enough empirical support to understand how it works and how to get the most out of it. The exact relationship between the applied current and neurons in different brain areas is unclear. We do not know if all areas respond the same, if it is possible to maintain the changes over time or if there is some type of adverse effect.

The effects that are described as therapeutic are not yet powerful enough to constitute a alternative nor have all the possibilities that electrical stimulation of the nervous system It allows. Also, the machines are likely to be too expensive at this time and do not compensate for the reduced therapeutic benefit they produce. Therefore, in order to evaluate the viability of the treatment with its economic cost, it is necessary to explore to what extent the therapeutic effects penetrate.

Scope of application

Transcranial electrical stimulation has been used successfully in the symptomatic treatment of various disorders such as Parkinson's disease, epilepsy or chronic pain. However, greater benefits are obtained in the treatment of acute symptoms after suffering neurological damage. For example, significant improvements have been made in symptoms such as spatial neglect after ischemia or trauma. improvement of naming capacity in aphasias caused by vascular accidents or recognition memory in patients with Alzheimer disease.

These therapeutic successes reflect that electrical stimulation enhances the plasticity of the brain, so that it is of special interest for the treatment of loss of neurocognitive functions due to atrophy or to neurodegeneration. We think of dementias, neurocognitive disorders, vascular accidents, tumors and trauma as the most striking candidates for this type of therapy.