A Wearable Device for Minimally-Invasive Behind-the-Ear EEG and Evoked Potentials

We present an unobtrusive and minimally invasive system for acquiring 8-channels of EEG behind the ear, to support brain activity monitoring in a socially acceptable fashion and outside clinical environments. Electrical performance are in line with those of clinical EEG systems (0.48 μVRMS integrated noise in the [0-100] Hz band, 106 dB CMRR) and setup is extremely fast, requiring only a mild cleaning of the skin before applying the device. The system can acquire typical brain activity rhythms and potentials evoked by sensory stimuli, which are at the basis of BCI systems. Current consumption is 6.2 rnA, plus 16 mA for Bluetooth® data transmission (4.5 hours life on a 100 mAh battery). The overall cost of components is below 50 USD.