Sarah received a new brain stimulation treatment to treat depression John Lok Photography LLC
One year ago, a woman suffering from severe depression tried a new radical treatment that involves placing electrodes in her brain. Sarah, who was the first to try the new technique, said that things have become easier. She asked not to be identified.
The treatment will be limited to those with severe depression. It involves two brain surgeries and days of recording brain electrical signals in order to determine a pattern of activity or neural biomarker for each individual's symptoms.
These results offer hope that a biomarker-based, personalised treatment for psychiatric disorders can be achieved, according to Katherine Scangos, University of California, San Francisco.
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The implant only fires when it is needed. It does this a few hundred times per day depending on the pattern of brain activity detected. An easier form of brain stimulation that is constantly on is used for Parkinson's disease movement disorder. The brain areas responsible are well-understood. Although continuous brain stimulation was tried in depression before, the results were mixed. This may be because the brain circuitry involved is not well understood and can vary from one person to another.
Scangos' team began by recording electrical activity in Sarah's brain from 10 different areas. Sarah then reported her mood over a period of 10 days. Sarah was depressed since childhood and couldn't be helped with any drug treatment or electroconvulsive therapy. She was having suicidal thoughts multiple times per hour before the surgery.
Sarah's symptoms became the most severe when she was examined. The investigation revealed that there was a pattern of activity called gamma brainwaves at her amygdalae. These are two structures deep within the brain that were previously linked to emotions.
The implant was activated in the right ventral capsule/ventralstriatum (VC/VS) and both the depression symptoms and gamma brainwaves were relieved. Sarah says that the stimulation was the best she had ever experienced. It made me feel so happy and it even helped with my depression.
It was already known that the VC/VS is involved in depression. In some trials of continuous brain stimulation, it was targeted. A few patients with severe depression had the region removed by brain surgery. It makes sense in the context of previous operations, according to Ludvic Zrinzo, University College London Hospitals, who performs such operations.
The new study used high-frequency stimulation to decrease brain activity. This is done by temporarily mimicking the effects and symptoms of surgery. The stimulation in Sarah's case has lowered the right VC/VS. This in turn dampens the gamma brainwaves of the right amygdala. Also, brain scans showed that these structures are closely connected in her brain.
Continue reading: How to lift the gloom from depression and deep brain stimulation
The team connected two permanent electrodes to the VC/VS so that one only fires when it detects gamma wave activity in the amygdala. It activates approximately 300 times per day for 6 seconds and is set at a lower intensity so Sarah doesn't notice. Scangos says that we don't want this to disrupt her life.
Sarah noticed a change in her mood after the device was turned on. She says it was gradual, and my perspective on the world has changed. It has been a virtuous circle upwards, and everything has become easier over time. It was again enjoyable to do hobbies. The device has helped me to stay positive even after a year of therapy.
Scangos will use the same approach with 11 more people.
Although the results are amazing, we should not assume that this will work for all, Keyoumars Ashkan, a London-based surgeon at Kings College Hospital, said that it is unlikely. It is possible that every person's brain circuitry, which affects mood, may be slightly different.
Although the initial results of continuous brain stimulation were impressive, randomised trials showed that not enough people got better to warrant widespread use.
The latest brain stimulation method is expensive and labor-intensive. It requires two surgeries and days of research. However, the same method is used by epilepsy patients who require recordings to be made in multiple brain regions to determine where their seizures start. Before they can have surgery to remove the damaged tissue, the recordings must be taken.
Ashkan says that if you are willing to spend the time and effort to get to know someone, you can make therapy more personal. This is what makes this so exciting.
Journal reference: Nature Medicine, DOI: 10.1038/s41591-021-01480-w
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