title: The design and hardware implementation of a low-power real-time seizure detection algorithm.
abstract: Epilepsy affects more than 1% of the world's population. Responsive neurostimulation is emerging as an alternative therapy for the 30% of the epileptic patient population that does not benefit from pharmacological treatment. Efficient seizure detection algorithms will enable closed-loop epilepsy prostheses by stimulating the epileptogenic focus within an early onset window. Critically, this is expected to reduce neuronal desensitization over time and lead to longer-term device efficacy. This work presents a novel event-based seizure detection algorithm along with a low-power digital circuit implementation. Hippocampal depth-electrode recordings from six kainate-treated rats are used to validate the algorithm and hardware performance in this preliminary study. The design process illustrates crucial trade-offs in translating mathematical models into hardware implementations and validates statistical optimizations made with empirical data analyses on results obtained using a real-time functioning hardware prototype. Using quantitatively predicted thresholds from the depth-electrode recordings, the auto-updating algorithm performs with an average sensitivity and selectivity of 95.3 +/- 0.02% and 88.9 +/- 0.01% (mean +/- SE(alpha = 0.05)), respectively, on untrained data with a detection delay of 8.5 s [5.97, 11.04] from electrographic onset. The hardware implementation is shown feasible using CMOS circuits consuming under 350 nW of power from a 250 mV supply voltage from simulations on the MIT 180 nm SOI process.
authors.affiliation: Department of Biomedical Engineering, Purdue University, West Lafayette, IN 47906, USA. sraghun@purdue.edu
authors.forename: Shriram
authors.initials: S
authors.lastname: Raghunathan
authors.forename: Sumeet K
authors.initials: SK
authors.lastname: Gupta
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Ward
authors.forename: Robert M
authors.initials: RM
authors.lastname: Worth
authors.forename: Kaushik
authors.initials: K
authors.lastname: Roy
authors.forename: Pedro P
authors.initials: PP
authors.lastname: Irazoqui
mesh_terms: D000465:Algorithms; D000818:Animals; D003936:Diagnosis, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D011211:Electric Power Supplies; D004569:Electroencephalography / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D051381:Rats; D020318:Rats, Long-Evans; D015203:Reproducibility of Results; D012640:Seizures / Q000175:diagnosis*; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*