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Biol Cybern (2013) 107:4959 DOI 10.1007/s00422-012-0523-5
ORIGINAL PAPER
Real-time change detection of steady-state evoked potentials
Gideon Nave Yonina C. Eldar Gideon Inbar
Alon Sinai Hillel Pratt Menashe Zaaroor
Received: 1 November 2011 / Accepted: 18 September 2012 / Published online: 5 October 2012 Springer-Verlag Berlin Heidelberg 2012
Abstract Steady-state evoked potentials (SSEP) are the electrical activity recorded from the scalp in response to high-rate sensory stimulation. SSEP consist of a constituent frequency component matching the stimulation rate, whose amplitude and phase remain constant with time and are sensitive to functional changes in the stimulated sensory system. Monitoring SSEP during neurosurgical procedures allows identication of an emerging impairment early enough before the damage becomes permanent. In routine practice, SSEP are extracted by averaging of the EEG recordings, allowing detection of neurological changes within
Hillel Pratt and Menashe Zaaroor contributed equally to this study.
G. Nave (B) Y. C. Eldar G. Inbar
Faculty of Electrical Engineering, Technion-IIT, 32000 Haifa, Israele-mail: [email protected]
Y. C. Eldare-mail: [email protected]
G. Inbare-mail: [email protected]
G. NaveDepartment of Computation and Neural Systems, California Institute of Technology, Mail stop 228-77, Pasadena, CA 91125, USA
A. Sinai M. Zaaroor
Department of Neurosurgery, Rambam Health Care Campus and Faculty of Medicine, Technion-IIT, Haifa, Israel e-mail: [email protected]
M. Zaaroore-mail: [email protected]
H. PrattEvoked Potentials Laboratory, Faculties of Medicine, and Biomedical Engineering, Technion-IIT, Haifa, Israel e-mail: [email protected]
approximately a minute. As an alternative to the relatively slow-responding empirical averaging, we present an algorithm that detects changes in the SSEP within seconds. Our system alerts when changes in the SSEP are detected by applying a two-step Generalized Likelihood Ratio Test (GLRT) on the unaveraged EEG recordings. This approach outperforms conventional detection and provides the monitor with a statistical measure of the likelihood that a change occurred, thus enhancing its sensitivity and reliability. The systems performance is analyzed using Monte Carlo simulations and tested on real EEG data recorded under coma.
Keywords Evoked potentials Neuro-monitoring
Change detection GLRT
1 Introduction
Evoked potentials (EP) are the electrical potential generated by the activity of neurons in the brain, and recorded from a human or animal following presentation of a stimulus. EP amplitudes are typically in the order of a microvolt, compared to tens or hundreds of microvolts for spontaneous EEG. EP consist of three...