Self-adjusting brain pacemaker may help reduce Parkinson disease symptoms

A small feasibility study funded by the National Institutes of Health (NIH) found that an implanted device regulated by the body’s brain activity could provide continual and improved treatment for the symptoms of Parkinson disease in certain people with the disorder. This type of treatment, called adaptive deep brain stimulation, is an improvement on a technique that has been used for Parkinson disease and other brain disorders for many years. The study found adaptive deep brain stimulation was markedly more effective at controlling Parkinson disease symptoms compared to conventional DBS treatments.

“This study marks a big step forward towards developing a DBS system that adapts to what the individual patient needs at a given time,” said Megan Frankowski PhD, program director for NIH’s Brain Research Through Advancing Innovative Neurotechnologies® Initiative, or The BRAIN Initiative®, which helped fund this project. “By helping to control residual symptoms while not exacerbating others, adaptive DBS has the potential to improve the quality of life for some people living with Parkinson’s disease.”

DBS involves implanting fine wires called electrodes into the brain at specific locations. These wires then deliver electrical signals that can help mitigate the symptoms of brain disorders such as Parkinson disease. Conventional DBS provides a constant level of stimulation and can also lead to unwanted side effects, because the brain does not always need the same strength of treatment. Therefore, adaptive deep brain stimulation uses data taken directly from a person’s brain and uses machine learning to adjust the level of stimulation in real time as the person’s needs change over time.

Four people already receiving conventional DBS were first asked what they felt was their most bothersome symptom that had persisted despite treatment. In many instances this was either involuntary movements or difficulty in initiating movement. The participants were then set up to receive adaptive deep brain stimulation treatment alongside their existing DBS therapy. After training the adaptive deep brain stimulation algorithm for several months, the participants were sent home, where the comparison test was performed by alternating between conventional and adaptive deep brain stimulation treatments. Changes occurred every two to seven days

Adaptive deep brain stimulation improved each participant’s most bothersome symptom roughly 50% compared to conventional DBS. Notably, even though they were not told which type of treatment they were receiving at any one time, three of the four participants were often able to correctly guess when they were on adaptive deep brain stimulation due to noticeable symptom improvement.

This project is a continuation of several years of work led by Philip Starr MD PhD, and colleagues at the University of California, San Francisco. Previously, in 2018, they reported the development of an adaptive DBS system, referred to as a “closed loop” system, that adjusted based on feedback from the brain itself. Later, in 2021, they described their ability to record brain activity in people as they went about their daily lives.

Here, those two findings were combined to use brain activity recorded during normal life activities to drive the adaptive deep brain stimulation system. However, DBS treatment changed brain activity so much that the signal that had been expected to control the adaptive deep brain stimulation system was no longer detectable. This required researchers to take a computational and data-driven approach to identify a different signal within the brains of people with Parkinson disease who were receiving conventional DBS therapy.

Conventional treatment for Parkinson disease often involves the drug levodopa, which is used to replace dopamine in the brain that has been lost because of the disorder. Because the amount of the drug in the brain fluctuates, peaking shortly after administration of the drug and gradually decreasing as it is metabolized by the body, adaptive deep brain stimulation could help smooth out the fluctuations by providing increased stimulation when drug levels are high and vice versa, making it an attractive option for patients requiring high doses of levodopa.

While these findings are promising, there remain significant challenges to overcome for this therapy to be more widely available. The initial setup of the device requires considerable input from highly trained clinicians. Researchers envision a future where most of the work would be managed by the device itself, greatly reducing the need for repeat visits to the clinic for fine tuning.

This type of automation is also necessary for other groups to test and eventually offer adaptive deep brain stimulation therapy in a clinical setting.

“One of the big issues facing deep brain stimulation, even in approved indications like Parkinson disease, is access, both for patients in terms of where they can get it and also the physicians who need special training to program these devices,” said Frankowski. “If there were a way for a system to find the most optimal settings at the press of a button, that would really increase the availability of this treatment for more people.”

Source: News Release
NIH/National Institute of Neurological Disorders and Stroke
August 19, 2024