BOLD correlates of continuously fluctuating epileptic activity isolated by independent component analysis

Jann, Kay; Wiest, Roland; Hauf, Martinus; Meyer, Klaus; Boesch, Chris; Mathis, Johannes; Schroth, Gerhard; Dierks, Thomas; Koenig, Thomas (2008). BOLD correlates of continuously fluctuating epileptic activity isolated by independent component analysis. NeuroImage, 42(2), pp. 635-48. San Diego, Calif.: Elsevier 10.1016/j.neuroimage.2008.05.001

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Combined EEG/fMRI recordings offer a promising opportunity to detect brain areas with altered BOLD signal during interictal epileptic discharges (IEDs). These areas are likely to represent the irritative zone, which is itself a reflection of the epileptogenic zone. This paper reports on the imaging findings using independent component analysis (ICA) to continuously quantify epileptiform activity in simultaneously acquired EEG and fMRI. Using ICA derived factors coding for the epileptic activity takes into account that epileptic activity is continuously fluctuating with each spike differing in amplitude, duration and maybe topography, including subthreshold epileptic activity besides clear IEDs and may thus increase the sensitivity and statistical power of combined EEG/fMRI in epilepsy. Twenty patients with different types of focal and generalized epilepsy syndromes were investigated. ICA separated epileptiform activity from normal physiological brain activity and artifacts. In 16/20 patients, BOLD correlates of epileptic activity matched the EEG sources, the clinical semiology, and, if present, the structural lesions. In clinically equivocal cases, the BOLD correlates aided to attribute proper diagnosis of the underlying epilepsy syndrome. Furthermore, in one patient with temporal lobe epilepsy, BOLD correlates of rhythmic delta activity could be employed to delineate the affected hippocampus. Compared to BOLD correlates of manually identified IEDs, the sensitivity was improved from 50% (10/20) to 80%. The ICA EEG/fMRI approach is a safe, non-invasive and easily applicable technique, which can be used to identify regions with altered hemodynamic effects related to IEDs as well as intermittent rhythmic discharges in different types of epilepsy.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > University Psychiatric Services > University Hospital of Psychiatry and Psychotherapy > Psychiatric Neurophysiology [discontinued] 04 Faculty of Medicine > Department of Radiology, Neuroradiology and Nuclear Medicine (DRNN) > Institute of Diagnostic and Interventional Neuroradiology 04 Faculty of Medicine > Department of Intensive Care, Emergency Medicine and Anaesthesiology (DINA) > Clinic and Policlinic for Anaesthesiology and Pain Therapy 04 Faculty of Medicine > Department of Radiology, Neuroradiology and Nuclear Medicine (DRNN) > Institute of Diagnostic, Interventional and Paediatric Radiology > DCR Magnetic Resonance Spectroscopy and Methodology (AMSM) 04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Neurology
UniBE Contributor:	Jann, Kay, Wiest, Roland Gerhard Rudi, Hauf, Martinus, Meyer, Katrin Susanne, Boesch, Christoph Hans, Mathis, Johannes, Schroth, Gerhard, Dierks, Thomas, König, Thomas
ISSN:	1053-8119
ISBN:	18585061
Publisher:	Elsevier
Language:	English
Submitter:	Jeannie Wurz
Date Deposited:	04 Oct 2013 15:01
Last Modified:	02 Mar 2023 23:22
Publisher DOI:	10.1016/j.neuroimage.2008.05.001
PubMed ID:	18585061
Web of Science ID:	000258695200020
URI:	https://boris.unibe.ch/id/eprint/26682 (FactScience: 81170)