A fully integrated 8-channel closed-loop neural-prosthetic cmos soc for real-time epileptic seizure control
Journal
IEEE Journal of Solid-State Circuits
Journal Volume
49
Journal Issue
1
Pages
232-247
Date Issued
2014
Author(s)
Abstract
An 8-channel closed-loop neural-prosthetic SoC is presented for real-time intracranial EEG (iEEG) acquisition, seizure detection, and electrical stimulation in order to suppress epileptic seizures. The SoC is composed of eight energy-efficient analog front-end amplifiers (AFEAs), a 10-b delta-modulated SAR ADC (DMSAR ADC), a configurable bio-signal processor (BSP), and an adaptive high-voltage-tolerant stimulator. A wireless power-and-data transmission system is also embedded. By leveraging T-connected pseudo-resistors, the high-pass (low-pass) cutoff frequency of the AFEAs can be adjusted from 0.1 to 10 Hz (0.8 to 7 kHz). The noise-efficiency factor (NEF) of the AFEA is 1.77, and the DMSAR ADC achieves an ENOB of 9.57 bits. The BSP extracts the epileptic features from time-domain entropy and frequency spectrum for seizure detection. A constant 30-μA stimulus current is delivered by closed-loop control. The acquired signals are transmitted with on-off keying (OOK) modulation at 4 Mbps over the MedRadio band for monitoring. A multi-LDO topology is adopted to mitigate the interferences across different power domains. The proposed SoC is fabricated in 0.18-μm CMOS and occupies 13.47 mm2. Verified on Long Evans rats, the proposed SoC dissipates 2.8 mW and achieves high detection accuracy (> 92%) within 0.8 s.
Subjects
Closed-loop control; Epilepsy; Neural prosthesis; Neuron modulation; System-on-Chip (SoC); Wireless power transmission
Other Subjects
Closed-loop control; Detection accuracy; Electrical stimulations; Epilepsy; On-off keying modulations; System-On-Chip; Transmission systems; Wireless power transmission; Application specific integrated circuits; Computation theory; Cutoff frequency; Modulation; Neural prostheses; Neurophysiology; Prosthetics; Analog to digital conversion
Type
journal article