Wednesday , December 1 2021

Electric Hair Implants: A New Way To Treat Depression?



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Sarah had suffered five years of torture from severe and untreatable depression. “Every day, I forced myself to resist the suicidal impulses that came to me several times an hour,” says the 36-year-old Californian.

Then a surgical team at the University of California, San Francisco, inserted a thin thread deep into their brains – and gave a gentle electric pulse. “When I first got the stimulation, the ‘aha’ moment happened,” says Sarah, who only wants to be known by her first name. “I felt the most intense happy sensation and my depression was for a moment a distant nightmare.”

After the UCSF scientists discovered which part of Sarah’s brain was associated with negative emotions and which would respond to a diminishing stimulus, they incorporated their findings into a permanent implant that acts as a neural pacemaker. After wearing the device for a year, she reports that it “kept depression at bay, allowing me to return to my best self and rebuild a life worth living”.

UCSF researchers praised their performance, published Monday in Nature Medicine, as a landmark in an effort to develop personalized treatments for depression using neural electronics. For the first time, researchers have identified and modulated a brain circuit that is uniquely associated with the symptoms. To date, procedures that apply electricity to the patient’s brain have adopted a “one-size-fits-all” approach.

A man is pictured in a lighted apartment in a building
Evidence is emerging that the Covid-19 pandemic and lockdowns have substantially prevented the occurrence of depression and other mental health problems © Kirill Kudryavtsev / AFP via Getty Images

Neuroscientists not involved in the project agreed that it was an important step forward, while warning that it would take many years of work to convert an expensive and time-consuming surgical procedure into something that could be expanded. applied to unreliable depression. Patients with other psychiatric conditions may also benefit from personalized deep brain stimulation, such as those with Parkinson’s disease and epilepsy who have already been treated with DBS.

Sameer Sheth, a neurosurgeon at Baylor College of Medicine in Texas, says he is “super-excited” by the UCSF work and adds that he is conducting a similar neurotechnology test in unreliable depression, which has yielded similarly encouraging results with the first participant, although they have not yet been published. “We all recognize that some patients need an individualized approach,” he says.

Find the ‘biomarkers’

The unmet medical need is enormous. According to the World Health Organization, 280 million people worldwide suffer from severe depression, of which about 30 percent do not respond well to existing treatments: psychotherapy, antidepressant medication or electroconvulsive therapy. And evidence is emerging that the Covid-19 pandemic has substantially increased the incidence of depression and other mental health problems for all age groups, including children.

Electroconvulsive therapy was the first psychiatric treatment with electricity, although it works in a very different way than the individualized deep brain stimulation used in the UCSF and Baylor trials.

ECT still suffers from a “brainwashed” reputation from the mid-20th century, when large pulses were given without anesthesia, sometimes leading to memory loss, broken bones and other serious side effects. Today, ECT is performed under general anesthesia, with milder currents passing through the brains of electrodes on the scalp, causing a brief attack that somehow restores neuronal circuits such as chemistry. No one really knows how it works – and it does not benefit everyone – but an estimated 100,000 people a year undergo ECT in the US alone.

Nurses attend a patient receiving electro-convulsive therapy for depression in a mental hospital in England in 1946

Nurses Attend A Patient Receiving Electro-Convulsive Therapy To Cure Depression In A Mental Hospital In England In 1946 © Kurt Hutton / Picture Post / Hulton Archive / Getty Images

The UCSF and Baylor teams are not the first to study deep brain stimulation for depression, but previous trials with simpler devices that have delivered a continuous stimulus in one place have yielded mixed results. Two DBS trials sponsored by medical technology companies were stopped early because they did not provide clear benefits.

“It was perhaps naive of us to think that such a heterogeneous condition as depression could be treated in the same way for different patients,” says Darin Dougherty, director of neurotherapeutics at Massachusetts General Hospital, who conducted one of the discontinued trials. in charge of.

DBS has become a routine and effective treatment for epilepsy and Parkinson’s disease, in which scientists know which brain regions to target. The problem with applying neuroelectronics to depression in the same way has been that scientists do not know enough about the particular brain circuits associated with the condition.

The key discovery of the UCSF team was a “biomarker” indicating the onset of depressive symptoms, a specific pattern of neural activity in a brain area called the amygdala that treats responses to threats. A stimulus there did not leave Sarah’s symptoms, but the researchers found another site, the ventral striatum, where small electrical pulses immediately lifted unwanted sensations when they were discovered in the amygdala. The electronics control is a matchbox-sized device adapted from a $ 30,000 implant that is commercially available for epilepsy.

“This is an exciting step forward because of the adapted nature of stimulation,” says Jonathan Roiser, Professor of Neuroscience and Mental Health at University College London. “It is likely that if they are tested in other patients, different admission and stimulation sites would be required because the exact brainstem underlying symptoms are likely to differ between individuals.”

Patient Sarah in a clinic with psychiatrist Katherine Scangos, who passed the UCSF test
Patient Sarah in a clinic with psychiatrist Katherine Scangos, who conducted the UCSF trial © Maurice Ramirez, UCSF

Katherine Scangos, the psychiatrist leading the UCSF trial, has recruited two more patients with major depression to participate and is targeting 12 volunteers in total. “We have a lot to learn about variability across different patients and different types of depression,” she says.

Even if ongoing clinical trials of personalized DBS for depression at UCSF and Baylor show that the technology works just as well in cases other than for Sarah, “this type of highly invasive surgical procedure would only be used in the most patients with untreatable symptoms, ”says Roiser.

But UCSF neurosurgeon Ed Chang points out that there is a lot of room for improvement in DBS technology, which is based on the electronic circuit that was developed for heart voices 30 to 40 years ago. “What we do now is relatively rough compared to what I think the future may offer,” he says.

UCSF scientists also think about patent rights. “Companies that manufacture medical devices will need some intellectual property or patents to invest the resources – tens of millions of dollars – to conduct a formal trial,” says Chang. “We are investigating that because we are very serious about trying to understand if this could be a future therapy.”

Looking further ahead, researchers hope that insights into the brain circuit involved in depression obtained from personalized DBS can be used to develop non-invasive electronic treatments. “We really hope this will be something that can scale to other technologies in the future that may not even exist now,” Chang says.

Electrodes in the UCSF test stimulate brain regions only one millimeter or 1.5 mm across. There is no obvious way to achieve such precision with non-invasive targeting from outside the skull, although highly concentrated ultrasound beams are one possibility.

Roiser points out that two existing non-invasive electronic treatments, both milder in their impact than ECT, improve symptoms in many patients, although neither has a reliable effect on severe, unreliable depression.

The stronger of the two is transcranial magnetic stimulation (TMS), in which a coil placed against the scalp provides a magnetic pulse to stimulate nerve cells in the brain region involved in voice control. The most gentle method of stimulating the brain electrically is transcranial direct current stimulation (tDCS), which sends a weak electric current across the brain.

“There have been some studies trying to incorporate these non-invasive techniques into better and more tailored treatments,” says Roiser. But they do not come close to the new DBS methods in their precision.

A robot used to implant wires is seen in a still image video provided by Neuralink
Elon Musk’s Neuralink aims to continue helping quadriplegics communicate to ‘treat various brain-related ailments’ © Neuralink via Reuters

‘Virtual spiral upwards’

Another form of neurotechnology that has not yet been applied to psychiatry, but may in the future, is the brain-computer interface (BCI), which requires more data processing power than the electronic devices used for depression.

This field of research has so far concentrated on recording neural activity for unidirectional communication of the brain to a device outside. For example, if the BCI intends to relocate a limb, severely disabled patients may ride a robotic arm or artificially stimulate their own muscles to bypass a back wall injury. The technology also promises to open a window into the minds of people whose brains are too damaged to communicate with the outside world in any other way.

Two-way communication between brain and computer could eventually help people with psychiatric and neurological disorders. The most well-known and richly funded BCI company, Elon Musk’s Neuralink, aims to continue helping quadriplegics communicate to “treat various brain-related ailments”, the company said when it raised another $ 205 in August million raised in a Series C funding round.

But all that lies well in the future. “We have to emphasize that we are at a very early stage in the development of BCIs,” says Roiser, “and the idea that we can finally read the human neural code is very far-fetched.”

For now, Sarah is happy with the new life her DBS device has given her. “Depression controlled my life. I barely moved and barely did anything. I had to… Learn activities back and the things I like to do,” she says. “It simply came to our notice then. Everything has become easier and easier and easier. ”

Sarah also hopes the project will help overcome the widespread stigma attached to people with depression, “the feedback we get from the people around us in society that it is a moral failure”.

Scangos, her psychiatrist, says the invisible causes of depression do not help either. “I think some of the stigma comes from the ‘black box’ nature of the disorder,” she says. “We hope this will be resolved as we begin to define the biological substrates of depression and hopefully this study will allow us to do this for one patient at a time.”

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