NIRS-measured oxy- and deoxyhemoglobin changes associated with EEG spike-and-wave discharges in a genetic model of absence epilepsy: the GAERS.
OBJECTIVE
Absence epilepsy may be severe and is frequently accompanied by cognitive delay, yet its metabolic/hemodynamic aspects have not been established. The Genetic Absence Epilepsy Rats from Strasbourg (GAERS) are an isomorphic, predictive, and homologous model of human absence epilepsy. We studied hemodynamic changes related to generalized spike-and-wave discharges (GSWDs) in GAERS by using a technique with high temporal resolution: near-infrared spectroscopy (NIRS). We hypothesized that conflicting results from other techniques might be due to the averaging of a biphasic response such as the one we described in children.


METHODS
NIRS is particularly suitable for monitoring changes in the concentrations of oxy-, deoxy-, and total hemoglobin (HbO₂, HHb, and HbT), using the specific absorption properties of living tissues in the near infrared range. We obtained concomitant high quality electroencephalography (EEG)-NIRS recordings in six GAERS (total of 444 seizures), and tested whether the discharges were related to changes in cardiac or respiration rates.


RESULTS
The onset of GSWDs was preceded by a deactivation, followed by an activation that was possibly due to seizure-suppression mechanisms. The end was marked by a deactivation. The onset of GSWDs was associated with a decrease and the end with a brief increase in respiratory rate.


CONCLUSIONS
Our results differ partially from those of previous studies on hemodynamic aspects of GSWDs (many of which describe a simple deactivation), probably due to differences in temporal resolution and data processing; however, they are consistent with metabolic studies, functional magnetic resonance imaging (fMRI) studies on WAG/Rij rats, and some results in children with absence epilepsy.
Roche-Labarbe
Nadège
N
GRAMFC, EA 4293, Faculty of Medicine, University of Picardy, Amiens, France. gramfc.pub@u-picardie.fr
Zaaimi
Boubker
B
Mahmoudzadeh
Mahdi
M
Osharina
Victoria
V
Wallois
Alice
A
Nehlig
Astrid
A
Grebe
Reinhard
R
Wallois
Fabrice
F
D000704:Analysis of Variance; D000818:Animals; D001345:Autoradiography; D004195:Disease Models, Animal; D004562:Electrocardiography / Q000379:methods; D004569:Electroencephalography / Q000379:methods*; D004832:Epilepsy, Absence / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D006331:Heart Diseases / Q000209:etiology; D006454:Hemoglobins / Q000378:metabolism*; D008297:Male; D008957:Models, Genetic; D010108:Oxyhemoglobins / Q000378:metabolism*; D010991:Plethysmography / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D012120:Respiration Disorders / Q000209:etiology; D019265:Spectroscopy, Near-Infrared
D006454:Hemoglobins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin