Noninvasive continuous functional near‐infrared spectroscopy combined with electroencephalography recording of frontal lobe seizures

Abstract

Summary Purpose: To investigate spatial and metabolic changes associated with frontal lobe seizures. Methods: Functional near‐infrared spectroscopy combined with electroencephalography (EEG‐fNIRS) recordings of patients with confirmed nonlesional refractory frontal lobe epilepsy (FLE). Key Findings: Eighteen seizures from nine patients (seven male, mean age 27 years, range 13–46 years) with drug‐refractory FLE were captured during EEG‐fNIRS recordings. All seizures were coupled with significant hemodynamic variations that were greater with electroclinical than with electrical seizures. fNIRS helped in the identification of seizures in three patients with more subtle ictal EEG abnormalities. Hemodynamic changes consisted of local increases in oxygenated (HbO) and total hemoglobin (HbT) but heterogeneous deoxygenated hemoglobin (HbR) behavior. Furthermore, rapid hemodynamic alterations were observed in the homologous contralateral region, even in the absence of obvious propagated epileptic activity. The extent of HbO activation adequately lateralized the epileptogenic side in the majority of patients. Significance: EEG‐fNIRS reveals complex spatial and metabolic changes during focal frontal lobe seizures. Further characterization of these changes could improve seizure detection, localization, and understanding of the impact of focal seizures.

Exploring the capability of wireless near infrared spectroscopy as a portable seizure detection device for epilepsy patients

“…Initial qualitative analysis of NIRS-data from the seizures revealed most hemodynamic changes to occur just before or in the first minutes after seizure onsets in accordance with previous NIRS studies [3,6]. We did not find any trend of changes in the pre-ictal periods, which in general exceeded the ictal-periods of the seizures.…”

Hypoxia inducible factor-1α expression is associated with hippocampal apoptosis during epileptogenesis

“…Thus, these results indicated that hypoxia acted on the hippocampus with regional character in the SE, which was in line with hippocampal sclerosis in a postmortem study (Feast et al, 2012). Furthermore, Oxygen deprivation of the CA1, CA3 and DG of the hippocampus during epileptic seizures has been verified with MRI and EEG recording (van Eijsden et al, 2004;Nguyen et al, 2013). So studying hypoxic insults in these sub-regions may reveal the mechanism of hippocampal apoptosis in a rat model of epilepsy.…”

Application of near-infrared spectroscopy in clinical neurology

“…NIRS revealed significant hyperperfusion on the side of seizure foci compared with ictal single-photon-emission computed tomography in recordings of patients with nonlesional refractory frontal-lobe epilepsy. 48,49 NIRS and electroencephalography (EEG) were successfully applied simultaneously to the mouse brain to spatiotemporally track hemodynamics responses to epileptic episodes that had been induced pharmacologically. 50 Another study combining NIRS and EEG has also revealed complex local and distant oxygenation changes during temporal-lobe seizures, 51 and so this methodology can be expected to be actively used in clinical researches.…”