Key Points
- Research teams from the University of Oxford and University College London built a novel neuromodulation system to reach precise brain targets.
- The team plans to treat a variety of disorders, including Parkinson’s disease, schizophrenia, stroke, pain, and depression.
Ultrasound System for Precise Neuromodulation of Human Deep Brain Circuits
A collaborative team of researchers based in the United Kingdom recently published an article describing their newly designed focused ultrasound brain treatment system. The project’s co-lead investigators are Charlotte J. Stagg, MRCP, DPhil, head of the University of Oxford’s Nuffield Department of Clinical Neurosciences Physiological Neuroimaging Group, and Bradley E. Treeby, PhD, honorary professor of Biomedical Ultrasound in the Department of Medical Physics and Biomedical Engineering at University College London (UCL).
Under development for more than 10 years, the transcranial ultrasound device is designed for precise deep brain neuromodulation. Its custom-built, semi-ellipsoidal–shaped helmet houses 256 ultrasound transducers that are guided by real-time functional MRI (fMRI) monitoring. The system’s operating frequency is 555 kilohertz (kHz), adding variety with other low-intensity focused ultrasound systems that are currently on the market.
When asked about the motivation to design a completely novel device, Dr. Stagg said, “While reviewing the trade-offs between depth of penetration versus target size, we identified a need to deliver more localized and precise neuromodulation. We were particularly interested in reaching deep brain structures, such as the thalamic nuclei.”
The system includes a soft, custom-designed stereotactic face and neck mask for positioning, a model-based treatment planning method, and an online targeting system for maintaining accuracy across treatments.
“The head positioning system holds the subject still with an average movement between sessions of 1.5 mm and within sessions of 0.25 mm,” said Dr. Treeby. “To further improve accuracy, our software measures the actual position of the subject in the helmet and adjusts the driving phases for each ultrasound element accordingly. This step creates submillimeter targeting precision.”
Compared with other low-intensity brain systems, the UK device uses the above-described customized stereotactic mask for patient positioning, incorporates smaller, less-directional transducer elements to increase its steering range across the deep brain, and targets via a treatment planning process that accounts for skull aberration and attenuation.
To test the system, the team asked healthy volunteers to perform visual checkerboard tasks while inside of the MRI. The fMRI measured activation in the lateral geniculate nucleus of the brain. These studies confirmed the device’s ability to target and modulate this deep target. The research team now plans to use the device to study brain function and develop treatments for neurological and psychiatric disorders, such as Parkinson’s disease, schizophrenia, stroke recovery, pain, depression, and other conditions.
Funding for the study was provided by the Engineering and Physical Sciences Research Council (EPSRC), Wellcome, and the NIHR Oxford Health Biomedical Research Centre.
Dr. Treeby became an honorary professor at UCL when he and his co-founders created a company to commercialize the technology. As a UCL spin-out company, NeuroHarmonics will develop a next-generation device with the same deep brain targeting precision but with improved accessibility (e.g., it will not be used within an MRI, and head shaving will not be necessary). The plan is to have a portable, wearable version of the system. Although NeuroHarmonics is not currently conducting any clinical trials, future studies are planned across a variety of indications, including essential tremor and depression.
See Nature Communications (Open Source)
See Media Coverage in The Guardian, Smithsonian Magazine, Newsweek, US News & World Report, Science Alert