S. Liu, C. Moncion, J. Zhang, L. Balachandar, D. Kwaku, J.J. Riera, J.L. Volakis, and J. Chae
Arizona State University, United States
Keywords: wireless sensor, fully passive sensor, neural recorder, brain machine interfaceExisting wireless neural interface systems often require intracranial wires to connect implanted electrodes to an external head-stage or / and deploy application specific integrated circuit (ASIC), that is battery-powered or externally power-transferred, raising safety concerns such as infection, electronics failure, or heat-induced tissue damage. This work presents a biocompatible, flexible, implantable neural recorder capable of wireless acquisition of neuropotentials without wires, batteries, energy harvesting units, or active electronics. The recorder, features a small footprint of 9x8x0.3mm^3, and is comprised of passive electronic components. The absence of active electronics on the device leads to near zero power consumption, inherently avoiding the catastrophic failure of active electronics. The implanted wireless recorder demonstrated its capability to capture neuropotentials of rat, including somatosensory evoked potentials (SSEP) and interictal epiletptiform discharges (IED). Wirelessly recorded SSEP and IED signals were directly compared to those from wired electrodes to demonstrate the efficacy of the wireless data. In addition, a CNN (Convoluted Neural Network)-based machine learning algorithm successfully achieved IED signal recognition accuracy as high as 100% and 91% in wired and wireless IED data, respectively. With further improvement, the recorder system presented in this work may find wide applications in future brain machine interface (BMI) system.