AN ON-CHIP PATIENT-SPECIFIC EEG CLASSIFICATION AND RECORDING PROCESSOR FOR WEARABLE ENVIRONMENTS
Masdar Institute of Science and Technology, UAE
Classification of EEG under wearable environment faces many challenges including motion artifact, electrode DC offset, noise and limited available energy source. This presentation describes the design consideration of a “patient-specific”, multichannel machine-learning based EEG classification and recording processors for wearable form-factor sensors. The goal is to optimize the detection performance while balancing the analog and digital signal processing to optimize its energy consumption. On-chip classification significantly helps achieving energy-efficiency by reducing the communication overhead of the data. With epileptic seizure detection and recording system examples, we start from choosing number of channels, the sampling rate, and how to effectively extract features out of the down-sampled data. After that, classification algorithms to achieve patient-specific detection are also discussed in detail. When verified with the Children’s Hospital BostonMassachusetts Institute of Technology (CHB-MIT) EEG database, based on Repeated Random SubSampling validation, the seizure detection sensitivity and specificity of the Non-Linear SVM (NL-SVM) are improved by 12.4%P and 3.56%P, respectively, compared to the Linear-SVM (LSVM). The LSVM and NLSVM processors are fabricated in 0.18µm 1P6M CMOS and consume 1.52µJ/classification and 1.34µJ/ classification, respectively. We will also discuss the hybrid type Dual Detector Architecture, which adopts two LSVM to balance the superior hardware efficiency of LSVM, while maintaining the detection accuracy. Finally, the on-chip memory requirements for storing the raw seizure data will be discussed.