title: Capturing the state transitions of seizure-like events using Hidden Markov models.
abstract: The purpose of this study was to investigate the number of states present in the progression of a seizure-like event (SLE). Of particular interest is to determine if there are more than two clearly defined states, as this would suggest that there is a distinct state preceding an SLE. Whole-intact hippocampus from C57/BL mice was used to model epileptiform activity induced by the perfusion of a low Mg(2+)/high K(+) solution while extracellular field potentials were recorded from CA3 pyramidal neurons. Hidden Markov models (HMM) were used to model the state transitions of the recorded SLEs by incorporating various features of the Hilbert transform into the training algorithm; specifically, 2- and 3-state HMMs were explored. Although the 2-state model was able to distinguish between SLE and nonSLE behavior, it provided no improvements compared to visual inspection alone. However, the 3-state model was able to capture two distinct nonSLE states that visual inspection failed to discriminate. Moreover, by developing an HMM based system a priori knowledge of the state transitions was not required making this an ideal platform for seizure prediction algorithms.
authors.affiliation: Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto M5S 3G9, Canada. mirna.guirgis@utoronto.ca
authors.forename: Mirna
authors.initials: M
authors.lastname: Guirgis
authors.forename: Demitre
authors.initials: D
authors.lastname: Serletis
authors.forename: Peter L
authors.initials: PL
authors.lastname: Carlen
authors.forename: Berj L
authors.initials: BL
authors.lastname: Bardakjian
mesh_terms: D000200:Action Potentials; D000818:Animals; D001683:Biological Clocks; D002478:Cells, Cultured; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D008390:Markov Chains; D051379:Mice; D008810:Mice, Inbred C57BL; D008959:Models, Neurological; D015233:Models, Statistical; D017966:Pyramidal Cells; D012640:Seizures / Q000503:physiopathology*