title: Visualizing spikes in source-space: Rapid and efficient evaluation of magnetoencephalography.
abstract: OBJECTIVE
  Reviewing magnetoencephalography (MEG) recordings is time-consuming: signals from the 306 MEG-sensors are typically reviewed divided into six arrays of 51 sensors each, thus browsing each recording six times in order to evaluate all signals. A novel method of reconstructing the MEG signals in source-space was developed using a source-montage of 29 brain-regions and two spatial components to remove magnetocardiographic (MKG) artefacts. Our objective was to evaluate the accuracy of reviewing MEG in source-space.
  
  
  METHODS
  In 60 consecutive patients with epilepsy, we prospectively evaluated the accuracy of reviewing the MEG signals in source-space as compared to the classical method of reviewing them in sensor-space.
  
  
  RESULTS
  All 46 spike-clusters identified in sensor-space were also identified in source-space. Two additional spike-clusters were identified in source-space. As 29 source-channels can be easily displayed simultaneously, MEG recordings had to be browsed only once. Yet, this yielded a global coverage of the recorded signals and enhanced detectability of epileptiform discharges because MKG-artefacts were suppressed and did not impede evaluation in source-space.
  
  
  CONCLUSIONS
  Our results show that reviewing MEG recordings in source-space is accurate and much more rapid than the classical method of reviewing in sensor-space.
  
  
  CONCLUSIONS
  This novel method facilitates the clinical use of MEG.
authors.affiliation: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Neurophysiology, Danish Epilepsy Centre, Dianalund, Denmark. Electronic address: sbz@filadelfia.dk.
authors.forename: Sándor
authors.initials: S
authors.lastname: Beniczky
authors.affiliation: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Lene
authors.initials: L
authors.lastname: Duez
authors.affiliation: Research Department, BESA GmbH, Graefelfing, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Scherg
authors.affiliation: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Peter Orm
authors.initials: PO
authors.lastname: Hansen
authors.affiliation: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Hatice
authors.initials: H
authors.lastname: Tankisi
authors.affiliation: Department of Neurology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Sidenius
authors.affiliation: Department of Neurology and Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Anne
authors.initials: A
authors.lastname: Sabers
authors.affiliation: Department of Neurology and Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Lars Hageman
authors.initials: LH
authors.lastname: Pinborg
authors.affiliation: Department of Paediatrics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Uldall
authors.affiliation: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Fuglsang-Frederiksen
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D004827:Epilepsy / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods* / Q000592:standards*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016037:Single-Blind Method; D013997:Time Factors; D055815:Young Adult
keywords: Artefact correction; Epileptiform activity; Magnetoencephalography; Source-montage; Source-space