A Baylor College of Medicine and Rice University researcher, Caleb Kemere, is developing a more advanced deep brain stimulator (DBS), which is designed to help erase tremors caused by Parkinson’s disease patients.
The device works by sending electrical currents deep into nerve centers close to the brain stem. Dr. Kemere is looking to improve upon the existing technology by making it automatically adjust itself many times per second, thus optimizing the operational capacity of DBS devices that are already on the market.
The technology currently in development is one of Kemere’s ongoing research initiatives that are focused on the basal ganglia, which is the part of the brain that controls movement.
“Deep brain stimulation has proven to be remarkably effective in treating Parkinson’s, and it may well turn out to be revolutionary for treating severe depression and other neurological and psychiatric disorders,” said Dr. Kemere, who serves as both an adjunct assistant professor of neurology at Baylor College of Medicine, and as an assistant professor of electrical and computer
engineering, specialized in electronic devices that interact with the brain. He is also the director of Rice’s Realtime Neural Engineering Laboratory.
Current DBS systems are proven to produce significantly positive results in Parkinson’s patients, some of which have been able to walk, speak, write, and regain other movements again. The system distributes a small and continuous current to the basal ganglia and it can be thought of as a “brain pacemaker.”
However, the current DBS systems are manually adjusted by neurologists, which forces patients to attend weekly appointments. Kemere’s concept is to create a system that can automatically adjust itself many times each second, thus avoiding the need for manual recalibrations. “We want to develop deep brain stimulation technology that operates on the order of milliseconds, actively detecting what’s going on in the brain at any moment and then modulating the stimulation to optimize results. In electrical engineering terms, we call this ‘closing the feedback loop,'” he explained.
The point of departure, for Kemere, is that “today’s DBS technology is basically the same as that used in heart pacemakers.” He went on to explain that, “the electrodes are just implanted inside the brain rather than in the heart. I’ve found that when electrical engineers like myself first hear about DBS, they generally have the same two thoughts: ‘Wow, that’s a really cool use of electronics,’ and ‘The brain doesn’t pulse like a heart; maybe we can improve this by matching the stimulation to the dynamic nature of the brain!”
Kemere believes that, though DBS is already effective, it provides only minimal therapeutic benefit “for perhaps a third” of Parkinson’s patients. With his research, he thinks it is possible to create a dynamic system that would substantially increase the effectiveness of the device.
“Also, current DBS technology has side effects, and we’d like to reduce those,” Kemere said. “For example, people with Parkinson’s have a spectrum of symptoms, including tremors, trouble initiating muscle movement, muscle rigidity and slowness of movement. Sometimes, DBS can relieve one of those symptoms but make another one worse.”
The next step of Kemere’s research is to work on the power system of the device, since the real-time computer processing required needs substantial power. The battery packs in current DBS systems last about 10 years, but it is more challenging to get the same kind of battery life in a more dynamic system.
The investigation will also involve the creation of algorithms to interpret the neural signals received from the brain. “We think we can optimize DBS stimulation and maximize its therapeutic benefit if we can better understand how information flows in the cortical-basal ganglia circuits in healthy brains, how those flows are disrupted by Parkinson’s disease and how DBS can alter those flows,” Kemere said. The experiments will be performed first with rats to create, test and refine systems.
The research was funded by a National Science Foundation (NSF) Career Award, which is only granted to 400 researchers each year, across all disciplines. Kemere will begin a five-year program to reboot DBS technology with the latest embedded processors and research analytics. The program is planned to support the research and career of young scholars. Each award consist of $400,000 in research funding.