A Versatile In-Ear Biosensing System for Continuous Brain and Health Monitoring.

To enable continuous, mobile health monitoring, body worn sensors need to offer comparable performance to clinical devices in a lightweight, unobtrusive package. This work presents a complete wireless electrophysiology data acquisition system (weDAQ) that is demonstrated for in-ear EEG with user-generic dry-contact electrodes made from standard printed circuit boards (PCBs). Each weDAQ device supports 16 channels, driven right leg, impedance scanning, 3-axis accelerometer data, local storage, high sampling rates, and adaptable data transmission modes. The weDAQ wireless platform supports body sensor networks (BSN) capable of aggregating multiple biosignal streams (EEG, EMG, EOG, etc.) by supporting simultaneous connectivity of multiple worn devices over the 802.11n WiFi protocol. Each channel achieves 28dB of gain over 70Hz bandwidth with a noise level of 0.92 mu Vpp and CMRR of 110.8 dB. In-ear and forehead EEG measurements taken from subjects captured modulation of alpha brain activity, EOG characteristic eye movements, and EMG from jaw muscles. The small footprint, performance, and flexibility of the weDAQ lay the foundation for online brain computer interface (BCI) experiments and smart, multimodal biosignal monitoring.