fNIRS-EEG study of focal interictal epileptiform discharges.
Functional near-infrared spectroscopy (fNIRS) acquired with electroencephalography (EEG) is a relatively new non-invasive neuroimaging technique with potential for long term monitoring of the epileptic brain. Simultaneous EEG-fNIRS recording allows the spatio-temporal reconstruction of the hemodynamic response in terms of the concentration changes in oxy-hemoglobin (HbO) and deoxy-hemoglobin (HbR) associated with recorded epileptic events such as interictal epileptic discharges (IEDs) or seizures. While most previous studies investigating fNIRS in epilepsy had limitations due to restricted spatial coverage and small sample sizes, this work includes a sufficiently large number of channels to provide an extensive bilateral coverage of the surface of the brain for a sample size of 40 patients with focal epilepsies. Topographic maps of significant activations due to each IED type were generated in four different views (dorsal, frontal, left and right) and were compared with the epileptic focus previously identified by an epileptologist. After excluding 5 patients due to the absence of IEDs and 6 more with mesial temporal foci too deep for fNIRS, we report that significant HbR (respectively HbO) concentration changes corresponding to IEDs were observed in 62% (resp. 38%) of patients with neocortical epilepsies. This HbR/HbO response was most significant in the epileptic focus region among all the activations in 28%/21% of patients.
Département de génie électrique, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-ville, Montréal, QC, Canada H3C3A7.
Ke
K
Peng
Service de neurologie, Hôpital Notre-Dame du CHUM, 1560 Rue Sherbrooke Est, Montréal, QC, Canada H3L4M1.
Dang Khoa
DK
Nguyen
Service de neurologie, Hôpital Notre-Dame du CHUM, 1560 Rue Sherbrooke Est, Montréal, QC, Canada H3L4M1.
Tania
T
Tayah
Centre de recherche, Hôpital Sainte-Justine, 3175 Chemin de la côte-Sainte-Catherine, Montréal, QC, Canada H3T1C5.
Phetsamone
P
Vannasing
Centre de recherche, Hôpital Sainte-Justine, 3175 Chemin de la côte-Sainte-Catherine, Montréal, QC, Canada H3T1C5.
Julie
J
Tremblay
Département de génie électrique, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-ville, Montréal, QC, Canada H3C3A7.
Mohamad
M
Sawan
Centre de recherche, Hôpital Sainte-Justine, 3175 Chemin de la côte-Sainte-Catherine, Montréal, QC, Canada H3T1C5; Centre de recherche en neuropsychologie et cognition, Département de psychologie, Université de Montréal, Montréal, QC, Canada H3C3J7.
Maryse
M
Lassonde
Département de génie électrique, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-ville, Montréal, QC, Canada H3C3A7; Institut de cardiologie de Montréal, Centre de recherche, 5000 Rue Bélanger Est, Montréal, QC, Canada H1T1C8.
Frédéric
F
Lesage
Département de génie électrique, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-ville, Montréal, QC, Canada H3C3A7; Institut de cardiologie de Montréal, Centre de recherche, 5000 Rue Bélanger Est, Montréal, QC, Canada H1T1C8. Electronic address: ph.pouliot@gmail.com.
Philippe
P
Pouliot
D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D058256:Brain Waves / Q000502:physiology; D002648:Child; D004569:Electroencephalography; D004827:Epilepsy / Q000378:metabolism* / Q000503:physiopathology*; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D019265:Spectroscopy, Near-Infrared; D055815:Young Adult
D006454:Hemoglobins; C100003:deoxyhemoglobin
EEG; Focal epilepsy; Interictal epileptic discharges; NIRS-SPM; fNIRS