Finite-Element Modeling Could Improve Brain Implant Design

imec

A European research group has developed a design strategy that it thinks will enhance brain implant functionality while reducing harmful side effects.

Used to treat such conditions as Parkinson's disease and essential tremor, deep brain stimulation (DBS) represents an emerging market poised for significant growth in the next several years. With the hope of improving brain implants, IMEC (Leuven, Belgium), Europe's largest independent research center focused on nanoelectronics and nanotechnology, presented a new design strategy for the development of brain implants this week at the Design, Automation & Test Europe (DATE) conference.Current DBS probes employ millimeter-size electrodes that stimulate the brain in an unfocused way and may have unwanted side effects, according to IMEC. Precise, targeted stimulation and fewer side effects could be enabled, IMEC suggests, through much-smaller electrodes. "To have a more-precise stimulation and recording, we need electrodes that are as small as individual brain cells," comments Wolfgang Eberle, senior scientist and project manager at IMEC's bioelectronics research group. "Such small electrodes can be made with semiconductor process technology, appropriate design tools, and advanced electronic signal processing. At DATE, we want to bring this message to the design community, showing the huge opportunities that the healthcare sector offers."Using finite-element modeling of the electrical field distribution around the brain probe, the group was able to develop prototype probes featuring 10-µm electrodes with various topologies. IMEC believes that this strategy could be the key to better brain implants.Finite-element modeling was performed using COMSOL multiphysics simulation software, which allowed the researchers to examine the mechanical properties of the probe during surgical insertion as well as to evaluate the effects of temperature on the device. The scientists found that by adapting the penetration depth and field symmetry, the electrical field could be steered around the probe, consequently delivering high-precision stimulation. To realize closed-loop systems, the researchers developed a mixed-signal compensation scheme that allowed for multielectrode probes equipped to provide dual functionality by way of stimulation and recording.