A Low-power Implantable Device for Epiletic Seizure Detection and Neurostimulation

In this paper, we present the design of a low-power closed-loop neurostimulator (CLNS) as an adjunctive treatment for patients with refractory partial epilepsy. The CLNS combines epileptic seizure detection with simultaneous electrical stimulation feedback. The system amplifies the neural signal with adjustable gain, detects epileptic low-voltage fast-activity, and generates programmable stimulation currents. The implemented seizure detector is based on a detection algorithm validated in Matlab tools and was tested using intracerebral electroencephalographic (iEEG) recordings from a patient with drug-resistant epilepsy. The amplifier, epileptic-seizure detector and electric stimulator were implemented using CMOS 0.18-mu m process. The iEEG were assessed by the proposed CMOS building blocks and the predefined seizure suppression biphasic electrical stimulations were administrated at 2 to 3 sec after electrographical seizure onsets. The simulated power consumption of the CLNS has showed that the system could run on a button cell battery for more than 8 years.