How a deep brain stimulation implant helped treat a woman's severe depression

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Doctors have successfully treated a patient with severe depression by resetting the brain circuitry involved in depressive brain patterns using a device that is the brain’s equivalent of a pacemaker.

The University of California (UCSF) the researchers discovered a neural biomarker, a specific pattern of brain activity that indicates the onset of depression in a patient, and customized a commercially available device to recognize this pattern and electrically stimulate another specific area of the brain.

By surgically implanting the device, the team, led by Katherine Scangos, assistant professor of psychiatry at UCSF’s Weill Institute of Neuroscience, created immediate “on-demand” therapy that was unique to the patient and to the patient. the neural circuit that triggers its processing. resistant depression.

“This study paves the way for a new paradigm that is desperately needed in psychiatry,” Andrew Krystal, professor of psychiatry and member of the UCSF Weill Institute for Neurosciences, said in a university press release. “We have developed a precision medicine approach that has successfully managed our patient’s treatment-resistant depression by identifying and modulating the circuit in her brain that is uniquely associated with her symptoms.”

The team’s proof of concept research is published in the journal Natural medicine.

The method used by the team is a form of deep brain stimulation (DBS), which has shown promise in the treatment of depression in clinical trials, but has shown little success. This could be because the markers in the brain that indicate the onset of depression vary from person to person.

While previous DBS methods provide constant stimulation to one area of the brain, the approach developed by the UCSF team takes into account that in different people, depression can involve different areas of the brain and identifies individual biomarkers.

Krystal points out that this personalized approach almost immediately relieved the symptoms of depression in the patient, a 36-year-old woman named Sarah. This relief lasted for the full 15 months she had the implant.

The team mapped Sarah’s stimulus-response over a 10-day period using electrodes implanted in her frontal cortex, lining up responses to the stimulation on a symptom rating scale she completed.

They found that when certain changes in the tonsil region of the brain occurred, Sarah’s symptoms diminished. When these changes did not occur, his depression did not subside.

They then implanted a NeuroPace RNS (Responsive NeuroStimulation) system in the right hemisphere of Sarah’s brain which constantly detected neurological activity in response to patterns the team had predefined. UCSF researchers also wirelessly collected 10-minute streams of data from Sarah’s brain as she went about her normal daily activities.

One electrode wire from the device was placed in the area of the brain where the biomarker was found and the other was connected to another area of Sarah’s brain where the team found that the stimulation resulted in relief. .

When the closed loop the team had created detected the biomarker in the first zone, they applied a tiny 1 milliampere (1/1000 of an ampere) of electricity to the second region for six seconds.

This caused a change in Sarah’s neural activity and confirmed to researchers that the changes in Sarah’s amygdala were indeed linked to her depression. Applying their closed-loop stimulation method to this marker improved the state significantly.

“I was on the end of the phone. I was severely depressed,” Sarah said in the UCSF press release. “Now those thoughts keep coming back, but it’s just… poof… the cycle stops.”

What the team cannot do from this trial is whether this individualized treatment might work for all patients. The team highlights the limitations of this proof of concept study in the Natural medicine paper. In addition to pointing out that this trial has a sample size of one, the team also points out that while Sarah didn’t know when the treatment was being applied, they were aware of the treatment themselves. This could have potentially skewed results.

The team hopes that as a result of this successful proof-of-concept study, their closed-loop neuromodulation method can be tested in much larger trials and could potentially provide relief to many people with chronic disease resistant to treatment depression, and other neuropsychiatric disorders because it helped Sarah.

“There is still a lot of work to be done,” Scangos said in the press release. “We need to look at how these circuits vary from patient to patient and repeat this work multiple times. And we need to see if an individual’s biomarker or brain circuit changes over time as treatment continues. . “