Brain stimulation: electricity against disease

The method has already proven itself in depression. Researchers are now investigating whether and how it helps with other diseases

Electrifying: brain stimulation via two electrodes (in the colored pillows)

© W & B / Berhard Kahrmann

The patient survived the allergic shock. But after he jumped from the shovel of death and was able to leave the intensive care unit, he was tormented by constant fatigue. This went on for years, despite all available means. Until Freiburg university physicians helped him with a method that one would have expected to be used at an esoteric seminar or in a late romantic horror novel. They applied electricity to his brain.

With success. The doctors awakened new spirits in the patient. Their need for daytime sleep fell by two thirds - over the course of a longer nap. "It is an individual observation that cannot easily be generalized," says the head of the study, Professor Christoph Nissen, putting the case history into perspective. "

Electrified nerves

Nissen, now chief physician of the University Psychiatric Services in Bern, Switzerland, is by no means the only one doing research in the field. The US military, for example, has been trying for several years to make soldiers more reactive and more alert using brain stimulation.

Therapy for the head: Dr. Kristoffer Féher from the University Clinic Bern is preparing an electrical brain stimulation. A weak current flows between two electrodes, which stimulates selected brain regions via the uninjured skullcap (simulated situation)

© W & B / Berhard Kahrmann

Similar techniques have long been established in medicine. Brain stimulation is the standard therapy for severe Parkinson's disease. If you're depressed, it could be that time soon. The so-called transcranial magnetic stimulation brightened the mood of patients in numerous studies.

In contrast to Parkinson's treatment (see graphic below), the electrical stimulus is administered through the closed skull. An operation is not necessary for magnetic or electrical stimulation. On closer inspection, however, the techniques and areas of application would differ considerably, emphasizes Professor Frank Padberg from the University of Munich: "The principles involved in modulating neuronal control circuits in the brain are completely different."

Magnet makes muscles twitch

With magnetic stimulation, a magnetic coil is held against the patient's head, which triggers a current flow in the brain for a fraction of a second. The current is strong enough to activate nerve cells - and thereby trigger muscle twitches, for example. This is why the method is also used in the diagnosis of neurological diseases when it comes to analyzing nerve tracts.

Deep brain stimulation: An alternative to the methods described in the article: In deep brain stimulation, electrodes are inserted through the skull.

© W & B / Astrid Zacharias

Treatment for Parkinson's disease

Electrodes are placed in specific areas of the brain called the subthalamic nucleus. The electrodes receive impulses from a pacemaker in the patient's chest, which inhibit this core area in the head. This has a positive effect on the patient's mobility. Similar therapies are also used for severe obsessive-compulsive disorders.

"With repeated stimulation in the left forehead area, however, we also see an antidepressant effect," explains Padberg. The effect only sets in after a few weeks, but is more than a placebo effect. The method for treating depression has been approved in the USA for a number of years.

How exactly it works, however, experts have only just begun to understand. It is assumed that the activated neurons in the frontal winds form new connections that are important for the regulation of emotions. Inhibitory influences and the altered metabolism of the nerves probably also play a role.

Mood enhancer electric shock

The mood-enhancing effect of therapeutic electric shock is known from a method that has so far been used as a drastic and ultimate means - for patients with severe depression for whom medication does not provide sufficient help: electroconvulsive therapy (ECT).

Epileptic seizures are triggered under controlled conditions and under anesthesia with electric shocks. "The ECT is very effective," says expert Nissen. "However, it often scares people and is not an option for everyone." Then magnetic stimulation could be a tried and tested alternative if drugs or psychotherapy do not have the desired effect.

Magnetic stimulation: The magnet held above the head causes a current to flow for a fraction of a second, which excites nerve cells in the outer cerebral cortex

© Action Press / Northwestern University

In addition to magnetic stimulation, transcranial electrical stimulation can also have beneficial effects. The brain is usually stimulated with a weak direct current. This is not sufficient for an immediate reaction of the nerves, but changes their threshold of excitability. This means that the treated area of ​​the brain is then activated more easily or less easily - depending on whether the stimulation is carried out with the plus or minus pole.

Still in the test phase

With activating stimulation, Christoph Nissen and his colleagues succeeded in driving away chronic fatigue. The opposite approach - that is, to trigger sleep with inhibitory application - failed in a current study. The problem: Even with direct current stimulation, it is only vaguely understood which brain centers are influenced how and what effects this has.

"This type of stimulation is not yet ready for clinical practice," emphasizes Nissen. "These are experimental approaches that we need to check in further studies." This also applies to other areas of application such as migraines or dementia.

After all: two years ago, a paper in the renowned New England Journal of Medicine showed that electrical stimulation lifts the mood of depressed people just as well as taking the tried and tested drug escitalopram - but not entirely without side effects.Some of the study participants suffered from ringing in the ears and increased nervousness after the therapy.

Neurologists from the Berlin Charité recently tested direct current stimulation on patients who had lost their speech as a result of a stroke. Applied in addition to intensive language training, the rehabilitation outcome of the participants improved. Apparently, the process supports brain networks in relearning language, concludes study director Professor Agnes Flöel, who now heads the Department of Neurology at the University of Greifswald. However, further investigations must follow before the method can be recommended for standard treatment.

With magnets against obsessive-compulsive disorder

Doctors are also exploring new possible uses for magnetic stimulation - albeit with varying degrees of success so far, as Frank Padberg reports: "Overall, the study results in psychoses such as schizophrenia and severe obsessive-compulsive disorder are interesting, but do not yet allow a conclusive assessment." Against severe obsessive-compulsive disorder, doctors sometimes use deep brain stimulation, which has proven itself as a therapy for Parkinson's disease.

Professor Christoph Nissen is the chief physician of the University Psychiatric Services in Bern

© W & B / Bernhard Kahrmann

This method is also effective in severe depression, as researchers from Bonn and Freiburg recently showed. To do this, however, electrodes have to be pushed deep into the brain (see graphic above). In addition to the risk of surgery and bleeding, this also brings with it possible psychological side effects such as manic states. "Such an intervention is therefore only justified if nothing else has helped," explains Christoph Nissen.

However, Frank Padberg considers self-stimulation to be riskier, as it is sometimes propagated on the Internet: "Something like this can be very dangerous." Electricity therapy on the brain belongs in the hands of professionals so that it is useful - and it doesn't end like a horror novel.