The value of multichannel MEG and EEG in the presurgical evaluation of 70 epilepsy patients

Epilepsy Res. 2006 Apr;69(1):80-6. doi: 10.1016/j.eplepsyres.2006.01.001. Epub 2006 Mar 3.


Objective: To evaluate the sensitivity of a simultaneous whole-head 306-channel magnetoencephalography (MEG)/70-electrode EEG recording to detect interictal epileptiform activity (IED) in a prospective, consecutive cohort of patients with medically refractory epilepsy that were considered candidates for epilepsy surgery.

Methods: Seventy patients were prospectively evaluated by simultaneously recorded MEG/EEG. All patients were surgical candidates or were considered for invasive EEG monitoring and had undergone an extensive presurgical evaluation at a tertiary epilepsy center. MEG and EEG raw traces were analysed individually by two independent reviewers.

Results: MEG data could not be evaluated due to excessive magnetic artefacts in three patients (4%). In the remaining 67 patients, the overall sensitivity to detect IED was 72% (48/67 patients) for MEG and 61% for EEG (41/67 patients) analysing the raw data. In 13% (9/67 patients), MEG-only IED were recorded, whereas in 3% (2/67 patients) EEG-only IED were recorded. The combined sensitivity was 75% (50/67 patients).

Conclusion: Three hundred and six-channel MEG has a similarly high sensitivity to record IED as EEG and appears to be complementary. In one-third of the EEG-negative patients, MEG can be expected to record IED, especially in the case of lateral neocortical epilepsy and/or cortical dysplasia.

Publication types

  • Evaluation Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Child
  • Electroencephalography*
  • Epilepsies, Partial / pathology*
  • Epilepsies, Partial / physiopathology
  • Epilepsies, Partial / surgery
  • Female
  • Humans
  • Magnetoencephalography*
  • Male
  • Middle Aged
  • Preoperative Care*
  • Prospective Studies
  • Sensitivity and Specificity