UC San Francisco researchers announced on June 16 the development of a new form of deep brain stimulation that adjusts in real time as a person walks, aiming to improve gait and reduce falls in people with Parkinson's disease.
The study, published June 15 in Nature Medicine, demonstrates for the first time that an implanted brain stimulator can detect neural signals associated with each step and automatically adjust stimulation within fractions of a second. The system is designed to respond to the brain's rhythm of walking, similar to how a cardiac pacemaker responds to heart rhythms.
More than 10 million people worldwide live with Parkinson's disease. While deep brain stimulation can help with tremor, stiffness, and slowness, many patients continue to struggle with gait impairment and falls. The UCSF team said one reason standard deep brain stimulation has limited effects on walking is because gait itself constantly changes and requires rapid coordination between the brain, spinal cord, and muscles. Conventional systems deliver fixed patterns regardless of activity.
To address this challenge, researchers developed a personalized adaptive system that identifies movement-related brain signals from each leg. These signals are embedded into the neurostimulator so it can automatically adjust therapy during every phase of walking without external input. "The brain contains remarkably rich information about movement," said Kenneth H. Louie, PhD, first author and UCSF post-doctoral scholar. "We found that we could identify neural signatures linked to each step and use them to guide stimulation in real time."
Five participants who had undergone surgery participated in laboratory testing using research electrodes placed over movement-related areas alongside their therapeutic leads. The adaptive system improved measures of gait symmetry and reduced variability in walking patterns during lab tests—markers associated with more stable gait.
Participants also completed a blinded multi-day crossover study at home; when the adaptive system was active, they experienced fewer falls while maintaining overall control of symptoms without serious adverse events reported. Researchers say larger studies are needed, but early results suggest timing stimulation directly to behavior may improve outcomes beyond what conventional continuous systems achieve.
"This study is about more than walking," Wang said. "It demonstrates that brain stimulation can adapt to what a person is doing in real time." Wang added, "Instead of delivering the same stimulation all day long, future devices may continuously listen to the brain and immediately respond to a patient's needs."
