A 16-Channel Patient-Specific Seizure Onset and Termination Detection SoC With Impedance-Adaptive Transcranial Electrical Stimulator

A 16-channel noninvasive closed-loop beginning-and end-of-seizure detection SoC is presented. The dual-channel charge recycled (DCCR) analog front end (AFE) achieves chopping and time-multiplexing an amplifier between two channels simultaneously which exploits fast-settling DC servo-loop with current consumption and NEF of 0.9 μA/channel and 3.29/channel, respectively. The dual-detector architecture (D2A) classification processor utilizes two linear support-vector machine (LSVM) classifiers based on digital hysteresis to enhance both the sensitivity and the specificity simultaneously. The pulsating voltage transcranial electrical stimulator (PVTES) automatically configures the number of pulses to control the amount of charge delivered based on skin-electrode impedance variation in efforts to suppress the seizure activity, while burning only 2.45 μW. The 25 mm² SoC implemented in 0.18 μm CMOS consumes 2.73 μJ/classification for 16 channels with an average sensitivity, specificity, and latency of 95.7%, 98%, and 1 s, respectively.