title: Decrease in haemoglobin oxygenation during absence seizures in adult humans.
abstract: Near-infrared spectroscopy (NIRS) is a noninvasive method that allows the assessment of activation-induced cortical oxygenation changes in humans. It has been demonstrated that an increase in oxygenated and a decrease in deoxygenated haemoglobin can be expected over an area activated by functional stimulation. Likewise, an inverse oxygenation pattern has been shown to be associated with cortical deactivation. The aim of the current study was to determine the oxygenation changes that occur during absence seizures. We performed ictal NIRS simultaneously with video-EEG telemetry in three adult patients with typical absence seizures. NIRS probes were placed over the frontal cortex below the F1/F2 leads. During all absence seizures studied, pronounced changes in cerebral Hb-oxygenation were noted and there were no changes in the interval. We observed a reproducible decrease in [oxy-Hb] and an increase in [deoxy-Hb] during absence seizures indicating a reduction of cortical activity. Oxygenation changes started several seconds after the EEG-defined absence onset and outlasted the clinically defined event by 20-30 s.
authors.affiliation: Neurologische Klinik und Poliklinik, Universitätsklinikum Charité, Medizinische Fakultät der Humboldt-Universität zu Berlin, Schumannstrasse 20/21, 10117 Berlin, Germany. katharina.buchheim@charite.de
authors.forename: Katharina
authors.initials: K
authors.lastname: Buchheim
authors.forename: Hellmuth
authors.initials: H
authors.lastname: Obrig
authors.forename: Wolfram
authors.initials: W
authors.lastname: v  Pannwitz
authors.forename: Anne
authors.initials: A
authors.lastname: Müller
authors.forename: Hauke
authors.initials: H
authors.lastname: Heekeren
authors.forename: Arno
authors.initials: A
authors.lastname: Villringer
authors.forename: Hartmut
authors.initials: H
authors.lastname: Meierkord
mesh_terms: D000328:Adult; D001921:Brain / Q000378:metabolism / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D015536:Down-Regulation / Q000502:physiology; D004569:Electroencephalography; D004832:Epilepsy, Absence / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D002534:Hypoxia, Brain / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D019265:Spectroscopy, Near-Infrared; D013686:Telemetry
chemical_list: D006454:Hemoglobins