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Small electrical shocks give healthier brains

Controversial electrotherapy has been replaced with small electrical impulses to the brain. This can help patients with depression, stroke and brain tumours.

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Marco Hirnstein, IBMP
Researcher Marco Hirnstein at the Faculty of Psychology, testing transcranial magnetic stimulation (TMS) on his own brain.
Photo:
Eirik Brekke, BT

Can stimulating the brain using an electric current help patients with different conditions? Researchers believe it could have positive effects on some conditions, and they already have interesting results.  This involves stimulating the brain with tiny-tiny electrical impulses in low-current therapy. But how and why does it work?

Researcher Marco André Hirnstein uses the brain stimulating devices to treat stroke or depression. Conditions that affect very many people. The devices are also used to treat people who hear voices, such as patients with schizophrenia, or perfectly healthy people. In addition, the researcher helps surgeons at Haukeland University Hospital in Bergen in preparation for operations on brain tumours.  

“It is highly satisfying to be a researcher and to be able to apply basic research directly in the treatment of patients,” says a dedicated Hirnstein.

Helps people with depression

Unfortunately, however, electrical brain stimulation still does not work for everyone. For example, even though it can be effective for many patients with depression, it may have little effect on other patients with the same condition.

“We need to do more research on this,” comments Hirnstein.  

He refers to other researchers who have found that the treatment is effective for two-thirds of the patients. For one third of the patients the treatment gave good long-term effects, while another third required a “top-up”. The last third experienced no effect at all. Thus, the treatment has different effects on different people, even if they have the same diagnosis. It is therefore particularly important for the researchers to find out why this is so, and how electrical brain stimulation affects the various psychological and neurological conditions. 

Hirnstein works and conducts research at the Department of Biology and Medical Psychology, Faculty of Psychology, University of Bergen, and collaborates closely with the academic departments at Haukeland University Hospital. He is involved in several of the projects under the auspices of the research group for Functional magnetic resonance imaging (fMRI), which is headed by Professor Karsten Specht. 

….not Jack Nicholson

There is a whole arsenal of methods that use an electric current to stimulate the brain. 

“But don't think of Jack Nicholson's rebellion against the treatment in One Flew Over the Cuckoo's Nest! 

That type of treatment is now only used for very severe depression and only under a general anaesthetic. Hirnstein and his colleagues use a much weaker electric current that only affects one specific, small area in the brain.  The current is about the same as that in a small battery, and it is not painful. The patient does not need an anaesthetic, and does not even notice it.

“Using these methods, we can "modulate" the selected area so that something in the brain is changed. Then we can help those who do not benefit from medication, as is the case for some patients with depression,” continues Hirnstein. 

The advantage of a brain with two halves

Hirnstein started this research because he was curious as to why our two brain hemispheres are so specialized. He explains that the left hemisphere controls our ability to write and to speak, while the right governs our ability to understand spatiality and to navigate.  

“We discovered that using electrical brain stimulation we could distinguish between the two hemispheres. It is actually a very convenient method to "reset" one half. That was when I became even more interested in the field. We can use the method to diagnose, treat and conduct research,” comments Hirnstein, who also collaborates with the neurologist Tom Eichele in this field.  

Targeting the correct area

If a tumour is located in the part of the brain that controls movement, surgeons must be certain when they operate that they know the location of the tumour as accurately as possible. This means the patient can avoid injury or paralysis. When Hirnstein has determined where the tumour is located in the brain and what surrounds it, the surgeon can feel more secure that he will hit the target correctly. By using electrical brain stimulation Hirnstein maps the precise areas that controls body movements. And with this method you don’t have to open up the skull. This information is then sent to the neurosurgeons.

“We determine which part of the body is controlled by precisely this area of the brain". 

The location of the area associated with a particular function of the body varies from person to person. The surgeon also performs his own tests during the operation, when the skull is open. 

“This means that the accuracy increases for these extremely demanding operations,” says Hirnstein. 

Re-finding words

Hirnstein uses a method called transcranial magnetic stimulation (TMS) to make the measurements with his device. When the researcher places the device on the head and presses the button, the brain receives a very mild form of electrical stimulation.

About 20,000 people in Norway have a stroke every year, and about a third of them subsequently have problems speaking (aphasia). This method can help patients with stroke to regain speech.

 “Some studies show that the patients who receive this treatment benefit more from language therapy,” states Hirnstein. 

Using TMS together with speech therapy is completely new in Norway and researchers need to find out more about this treatment. Therefore, together with colleagues Karsten Specht and Eike Wehling, he wants to introduce TMS also in Norway. The treatment is time consuming for the patient and researcher, and the outcome is still uncertain for some of these patients. Hirnstein explains that there are two ways to do this: Either stimulate the area around the part that is damaged, as our language centre is located in the left hemisphere, or attempt to dampen activity in the right hemisphere because this part of the brain will often strive to compensate for the injury.  

Voices in the head - help the researchers

Are the voices schizophrenics hear in their head real? Yes, doctors and researchers can see the changes in a specific area of the brain when this happens in the patient. 

 “People who do not have schizophrenia can also experience auditory hallucinations,” says Hirnstein.

He is working on an online survey on the prevalence of auditory hallucinations together with several other researchers. They are encouraging people to take part in the study. Those who have experienced hearing voices even when no one is talking, or those who hear their own thoughts as pronounced voices. The idea behind the study is that quite a few people have experienced auditory hallucinations without having  had a mental disorder. We want to find out how many this applies to in Norway and why they experience this phenomenon. 

“In this way, healthy people can help us to help those who really do suffer because they hear voices in their head,” comments Hirnstein. 

Not a cure for everything

“Electrical brain stimulation using a weak electric current is without doubt very beneficial in many disciplines. But we must also be clear that this is not a miracle therapy for all disorders,” states Hirnstein. 

Researchers still does not know enough about what exactly happens in the brain during treatment with weak electric current. Moreover, studies that use this method often have too few participants. That makes it difficult for the researchers to determine for whom this therapy will work. 

“There is therefore still a lot that needs to be researched in this aera in the future,” concludes Hirnstein enthusiastically.