A fully integrated wireless sensor-brain interface system to restore finger sensation

This paper presents a fully integrated wireless sensor brain machine interface system to restore continuous somatosensory feedback from the hand. A wireless bi-directional neural interface system-on-chip (SoC) and a wireless sensor node design are described in this work. The neural interface integrates a 16-channel neural recording front-end, a 16-channel electrical stimulation back-end, a successive approximation analog-to-digital converter (ADC), a custom digital controller, and an ultra-wide band (UWB) wireless transceiver. The sensor node features a custom designed optical force sensor, a low-power level-crossing ADC, an UWB transmitter, and analog interface to off-chip accelerometers. The optical force sensor is developed in standard CMOS with low-cost post fabrication. Multiple sensor nodes can be used to trigger pre-defined microstimulation in different brain areas for restoring finger sensation. The prototypes have been fabricated in 180nm standard CMOS technology. Bench testing and In-Vivo experimental results are presented in this paper. The system was designed to investigate the first chronic interface to the cuneate nucleus of macaques, and showed a promising solution for sensation restoration in future neuroprosthetics.