title: Multichannel continuous electroencephalography-functional near-infrared spectroscopy recording of focal seizures and interictal epileptiform discharges in human epilepsy: a review.
abstract: Functional near-infrared spectroscopy (fNIRS) has emerged as a promising neuroimaging technique as it allows noninvasive and long-term monitoring of cortical hemodynamics. Recent work by our group and others has revealed the potential of fNIRS, combined with electroencephalography (EEG), in the context of human epilepsy. Hemodynamic brain responses attributed to epileptic events, such as seizures and interictal epileptiform discharges (IEDs), are routinely observed with a good degree of statistical significance and in concordance with clinical presentation. Recording done with over 100 channels allows sufficiently large coverage of the epileptic focus and other areas. Three types of seizures have been documented: frontal lobe seizures, temporal lobe seizures, and posterior seizures. Increased oxygenation was observed in the epileptic focus in most cases, while rapid but similar hemodynamic variations were identified in the contralateral homologous region. While investigating IEDs, it was shown that their hemodynamic effect is observable with fNIRS, that their response is associated with significant (inhibitive) nonlinearities, and that the sensitivity and specificity of fNIRS to localize the epileptic focus can be estimated in a sample of 40 patients. This paper first reviews recent EEG-fNIRS developments in epilepsy research and then describes applications to the study of focal seizures and IEDs.
authors.affiliation: École Polytechnique de Montréal , Département de génie électrique and Institut de génie biomédical, C.P. 6079, Succursale Centre-ville, Montréal, Quebec H3C3A7, Canada.
authors.forename: Ke
authors.initials: K
authors.lastname: Peng
authors.affiliation: École Polytechnique de Montréal, Département de génie électrique and Institut de génie biomédical, C.P. 6079, Succursale Centre-ville, Montréal, Quebec H3C3A7, Canada; Institut de Cardiologie de Montréal, Centre de recherche, 5000 rue Bélanger est, Montréal, Quebec H1T1C8, Canada.
authors.forename: Philippe
authors.initials: P
authors.lastname: Pouliot
authors.affiliation: École Polytechnique de Montréal, Département de génie électrique and Institut de génie biomédical, C.P. 6079, Succursale Centre-ville, Montréal, Quebec H3C3A7, Canada; Institut de Cardiologie de Montréal, Centre de recherche, 5000 rue Bélanger est, Montréal, Quebec H1T1C8, Canada.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lesage
authors.affiliation: Centre Hospitalier de l'Université de Montréal , Hôpital Notre-Dame, Service de neurologie, 1560 rue Sherbrooke est, Montréal, Quebec H2L4M1, Canada.
authors.forename: Dang Khoa
authors.initials: DK
authors.lastname: Nguyen
keywords: electroencephalography-functional near-infrared spectroscopy; focal epilepsy; hemodynamic response; interictal epileptic discharge; seizure