title: Added diagnostic value of magnetoencephalography (MEG) in patients suspected for epilepsy, where previous, extensive EEG workup was unrevealing.
abstract: OBJECTIVE
  To elucidate the possible additional diagnostic yield of MEG in the workup of patients with suspected epilepsy, where repeated EEGs, including sleep-recordings failed to identify abnormalities.
  
  
  METHODS
  Fifty-two consecutive patients with clinical suspicion of epilepsy and at least three normal EEGs, including sleep-EEG, were prospectively analyzed. The reference standard was inferred from the diagnosis obtained from the medical charts, after at least one-year follow-up. MEG (306-channel, whole-head) and simultaneous EEG (MEG-EEG) was recorded for one hour. The added sensitivity of MEG was calculated from the cases where abnormalities were seen in MEG but not EEG.
  
  
  RESULTS
  Twenty-two patients had the diagnosis epilepsy according to the reference standard. MEG-EEG detected abnormalities, and supported the diagnosis in nine of the 22 patients with the diagnosis epilepsy at one-year follow-up. Sensitivity of MEG-EEG was 41%. The added sensitivity of MEG was 18%. MEG-EEG was normal in 28 of the 30 patients categorized as 'not epilepsy' at one year follow-up, yielding a specificity of 93%.
  
  
  CONCLUSIONS
  MEG provides additional diagnostic information in patients suspected for epilepsy, where repeated EEG recordings fail to demonstrate abnormality.
  
  
  CONCLUSIONS
  MEG should be included in the diagnostic workup of patients where the conventional, widely available methods are unrevealing.
authors: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark. Electronic address: leneduez@aarhus.rm.dk.
authors: Lene
authors: L
authors: Duez
authors: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Neurophysiology, Danish Epilepsy Centre, Dianalund, Denmark.
authors: Sándor
authors: S
authors: Beniczky
authors: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.
authors: Hatice
authors: H
authors: Tankisi
authors: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.
authors: Peter Orm
authors: PO
authors: Hansen
authors: Department of Neurology, Aarhus University Hospital, Aarhus, Denmark.
authors: Per
authors: P
authors: Sidenius
authors: Department of Neurology, Copenhagen University Hospital, Rigshospitalet-Blegdamsvej, Copenhagen, Denmark.
authors: Anne
authors: A
authors: Sabers
authors: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.
authors: Anders
authors: A
authors: Fuglsang-Frederiksen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004569:Electroencephalography; D004827:Epilepsy / Q000175:diagnosis*; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity
keywords: Diagnosis; Diagnostic yield; Electroencephalography; Epilepsy; Magnetoencephalography