Ultra-high-efficacy Wireless Neuromodulation Using a Conductive Ring Interface

An ab-initio physics study, supported with a COMSOL-based numerical simulation, presents a concept to enable wearable, highly targeted, and ultra-high-efficacy neuromodulation. A target site is defined by a relatively small gap of a miniaturized “ring”-shaped conductive interface implant. If the implant conductivity significantly exceeds the conductivity of the biological tissue, a highly localized electromotive force (emf) is induced in the ring upon application of an alternating current (AC) magnetic field. This emf generates an electric field in the gap, inducing local neural stimulation of the targeted site, e.g., translated to a nerve segment using circumferential cuffs. The wirelessly controlled autonomous stimulator implant acts as a low-resistance nearly-closed path to generate a highly localized electric field on the order of 50 V/m in the gap via application of a 1-kA/m AC magnetic field at a frequency of 10 kHz. The magnetic field is at least three orders of magnitude smaller than the magnetic field required to generate the same electric field strength via conventional transcranial magnetic stimulation. Therefore, this high-resolution, orientation-specific ring neuromodulation system could enable a highly localized, energy-efficient wearable device with significant preclinical and clinical potential.