EP 54. Modeling the effects of current steering with directional leads

Abstract

Background Deep brain stimulation (DBS) systems differ in designs and stimulation abilities. New developments in DBS are focusing on enabling directional stimulation capabilities that may possibly activate targets with greater specificity. We sought to use computational modeling to demonstrate that combining directional leads with Multiple Independent Current Control (MICC) may offer additional control over the shape of the Volume of Tissue Activated (VTA) using proposed lead designs from three different manufacturers. We also explore the effect of single and multiple source current control on directional stimulation with these leads. Methods Finite element models (COMSOL) were created for each lead and used to calculate the potentials in space (isotropic, homogenous, 0.1 S/m encapsulation layer, 500 μm thickness; 0.2 S/m bulk) due to unit currents on each electrode. These potentials were then used to evaluate neural activation using axon cable models (NEURON; MRG axon ( McIntyre et al., 2002 ). Results Modeled threshold fields iso-surfaced at relevant stimulation levels demonstrates the ability of MICC to enable selection and shaping of field profiles that are not possible when using single source systems. Conclusions Modeling results suggest additional clinical benefit may be achieved when coupling directional leads with MICC designs. These additional fields may result in clinical benefits for some patients, and further study will be needed to evaluate their effects.