Optimization of Lead Design and Electrode Configuration in Deep Brain Stimulation

Deep Brain Stimulation (DBS) is a medical treatment whose exact underlying biological mechanism is unknown. Yet, DBS is an established therapy in a number of neurological and mental disorders. Mathematical models aiming at a better understanding of DBS through the simulation of the electrical field in the brain have been developed in the past years. This study covers in silico optimization of the electrical stimuli delivered to the brain by means of a Finite Element model individualized through medical imaging data. The goal is to cover a given target volume with stimulation for full therapeutic effect while limiting the spread of the stimuli beyond the target border, to avoid undesirable side effects. The fraction of the activated tissue volume within the target and the fraction of the stimulation field that spreads beyond it are computed in order to quantify the performance of the stimuli. Two readily available leads are treated: a state-of-the-art lead using single active contact and a field-steering one in multiple active contact stimulation. Further, in order to obtain insights into lead design, hypothetical leads with different geometric characteristics are as well considered. The obtained results suggest that simplified models give a reasonably good approximation to optimal contact selection when compared to clinical data. Configurations with multiple active contacts might improve stimulation in some cases, although there is no general tendency. The lead design study suggests that row segmentation with three or four contacts per row is a good option. In addition, the stimulation performance was generally better for the designs where the contacts were closer to each other. This study thus confirms the importance of mathematical modeling in DBS as an inexpensive way of obtaining optimal stimulation settings and lead designs. Keywords–Deep Brain Stimulation; Optimization; Lead Design; Convex optimization; Field Steering; Parkinson Disease.