RESEARCH BRIEFS Deep Brain Stimulation Gets Responsive BY DELIVERING SMALL ELECTRICAL PULSES directly to the brain, deep
brain stimulation (DBS) can ease tremors associated with Parkinson’s disease, help relieve chronic pain, and even improve treatment for obsessive compulsive disorder (OCD) and depression. The technique works well for some patients, but researchers would like to make DBS devices a little smarter by adding the capability to sense activity in the brain and adapt the intensity of stimulation in real time. Brown University bioengineers have taken important steps toward creating adaptive DBS technology. Nature Medicine recently published the results of one study focused on identifying brain signals associated with OCD symptoms to treat the disease. OCD affects as much as 2% of the world’s population and can cause recurring unwanted thoughts and
repetitive behaviors. The disorder is often debilitating, and up to 40% of cases don’t respond to traditional drug or behavioral treatments. “In order to enable adaptive DBS for OCD, we must first identify the biomarkers in the brain associated with OCD symptoms, and that is what we are working to do in this study,” said DAVID BORTON, associate professor of engineering at Brown University, a biomedical engineer at the U.S. Department of Veterans Affairs Center for Neurorestoration and Neurotechnology, and senior author of the study. Led by Nicole Provenza ’21, a biomedical engineering PhD graduate from Borton’s laboratory, the research team collected brain signal data and a suite of behavioral biomarkers from study participants in both clinical and home settings. “This is the first time
Associate Professor of Engineering David Borton (right) demonstrates a deep brain stimulation device to doctoral students Michaela Alarie (left) and Ayan Waite (center).
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IMPACT 2022
brain signals from participants with neuropsychiatric illness have been recorded chronically at home alongside relevant behavioral measures,” Provenza said. “Using these brain signals, we may be able to differentiate between when someone is experiencing OCD symptoms and when they are not, and this technique made it possible to record this diversity of behavior and brain activity.” As the study advances to the next phase, signals recorded deep in the brain will now be considered along with signals from a second region of the brain, the orbital frontal cortex. Both regions are thought to play a role in OCD and other psychiatric disorders. Ayan Waite, a doctoral student in electrical engineering, studies the connectivity between the two regions and represents the relationship mathematically. That relationship can then be used as a control policy that continuously responds to neural data, modifying stimulation as necessary to reduce OCD symptoms. Meanwhile, biomedical engineering doctoral student Michaela Alarie is looking for new sets of biomarkers in the orbital frontal cortex. “I’m interested in looking at one behavior that someone with OCD might experience, such as pathological doubt or inflexibility, and seeing if there are any neurobiomarkers that represent that specific behavior,” Alarie said. Once a biomarker is identified, Waite can incorporate it into new closed-loop stimulation systems. “The work I’m doing now with closed-loop controls would be a very preliminary design,” said Waite. “There’s still so much to understand about mood and how it changes over time.” —kevin stacey
DEIRDRE CONFAR
Bioengineers develop adaptive DBS to adjust therapy as needed.
