Experimental research published in Nature. The technique uses deep brain stimulation to reactivate brain areas that have suffered moderate to severe traumatic injury. Promising results but further tests are needed
There deep brain stimulation a technique already used in the treatment of Parkinson’s, epilepsy, depression or chronic drug-resistant cluster headaches in which the functioning of the neurons needs to be restored with a little electrical stimulation which also recovers the response to drugs that have become ineffective. Now researchers at Stanford University (USA), who have also started a series of clinical trials on brain-computer interfaces capable of allowing patients affected by stroke or neurodegenerative disease to communicate, have treated six volunteers with a brain lesion with the same technique. moderate to severe traumatic injury (msTBI).
Research
As reported in the article published on Naturethe implantation of the device occurred without complications. Five participants completed the study and one of them had to drop out because he had developed a scalp infection. Before inserting the electrodes, the researchers subjected the volunteers to trail making
t
And
st , a neuropsychological test of visual attention and task switching. The test consists of connecting 25 consecutive “goals”, letters and numbers mixed together on a sheet of paper
as quickly as possible.
Starting one month after surgery, the remaining five volunteers underwent follow-up testing. On the letters and numbers exam, their scores jumped from 15 to 52 percent.
A blinded phase was also planned, in which half of the participants would have their devices turned off to check their response. Two of the patients refused, not wanting to take this risk. Of the three who participated in the shutdown phase, one was randomized with the device turned off. After three weeks without stimulation, that participant performed 34% slower on the trail creation test.
Gina’s story
One of the patients treated is called Gina Arata and agreed to tell her story on the Stanford University website
. In 2001, at the age of 22, while attending the last semester of college waiting to graduate and enroll in law school, was involved in a car accident and suffered a serious head injury. The injury had compromised his ability to concentrate so much that he struggled to even do a simple job of sorting mail.
I couldn’t remember anything, says Arata, who lives in Modesto (California) with his parents. My left foot was “dangled” so I was constantly stumbling. I have had other car accidents. Plus, I had no filter: I got angry very easily. Gina’s parents learned about the research being conducted at Stanford Medicine and contacted the University: the team of neurosurgeon Jaimie Henderson, co-senior author of the study together with neurologist Nicholas Schiff, of Weill Cornell Medicine University in New York, agreed to enroll the girl.
Now I don’t stumble anymore
In 2018, doctors surgically implanted a device deep in her brain, They then carefully calibrated the device’s electrical activity to stimulate the neural networks damaged by the injury. She immediately noticed the difference: When asked to list items at a grocery store, she could rattle off fruits and vegetables. Then a researcher turned off the device and couldn’t name any of them. I no longer received speeding fines from the facility, jokes Arata.
I don’t stumble anymore. I remember how much money is in my bank account. I couldn’t read, but after the implant I bought a book Where the Crawdads Sing, and I loved it and remembered it. And I no longer have the short temper I used to have.
The scope of application
The new technique, developed by researchers at Stanford Medicine and collaborators from other institutions, shows promise against long-term damage resulting from moderate to severe traumatic brain injury. In general, there is very little in the way of treatment for these patients, points out Professor Jaimie Henderson. But the fact that these patients had come out of the coma and had recovered a fair amount of cognitive functions suggested that brain systems that support attention and arousal – the ability to stay awake, pay attention to a conversation, concentrate on a task – were relatively preserved.
These systems connect the thalamus
points throughout the cortex, the outer layer of the brain, which controls higher cognitive functions. In these patients, such pathways are largely intact, but all have been downregulated, adds Professor Henderson. as if the lights had been dimmed and there wasn’t enough electricity to turn them back on.
The areas of the brain stimulated
In particular, an area of the thalamus called the lateral central nucleus it acts as a hub that regulates many aspects of consciousness. The central lateral nucleus is optimized for driving things in general, but its vulnerability is that if you have a multifocal lesion, it tends to be affected more because a stroke can come from almost anywhere in the brain, explains Professor Nicholas Schiff. The researchers hoped that precise electrical stimulation of the central lateral nucleus and its connections could reactivate these paths, turning the lights back on.
A virtual twin for precise positioning
In the study, researchers recruited five presenting participants Cognitive deficits more than two years after a moderate to severe traumatic brain injury. The volunteers ranged in age from 22 to 60, with injuries reported three to 18 years ago. The challenge was to place the stimulation device in exactly the right area, which varied from person to person. Initially, each brain was shaped differently, and lesions led to further changes. That’s why we developed a series of tools to better define what that area was, explains Professor Henderson.
The researchers created a virtual model of each brain which allowed them to pinpoint the location and level of stimulation that would activate the central lateral nucleus. Guided by these models, Henderson surgically implanted the devices into the five participants. It is important to “target” the area preciselyAnd he says. If you are even a few millimeters off target, you are out of the effectiveness zone.
Promising results
After a two-week analysis phase to optimize stimulation, participants spent 90 days with the device turned on for 12 hours a day. Their progress was measured using the trail making
t
And
st , a neuropsychological test of visual attention and task switching. The test consists of connecting 25 consecutive “goals”, letters and numbers mixed together on a sheet of paper
. a very delicate test precisely what we are observing: the ability to concentrate and plan, and to do so in a way that is sensitive to time, says Professor Henderson.
At the end of the 90 day treatment period, Participants improved their speed on the test by an average of 32 percent, far exceeding the 10 percent the researchers were aiming for. The only surprising thing was that it worked as we expected, which isn’t always a given, Henderson remarks.
For participants and their families, improvements were evident in their daily lives. They resumed activities that seemed impossible: reading books, watching TV programs, playing video games or finishing a homework assignment. They felt less tired and could get through the day without dozing. a pioneering moment, concludes Professor Schiff. Our goal now is to try to take systematic steps to make this a therapy. This is a sufficient signal for us to do our utmost.
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December 5, 2023 (modified December 5, 2023 | 2.44 pm)
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