Skip to main content

Advertisement

SpringerLink
Log in

Magnetoencephalography in the Preoperative Evaluation for Epilepsy Surgery

  • Epilepsy (CW Bazil, Section Editor)
  • Published:
Current Neurology and Neuroscience Reports Aims and scope Submit manuscript

Abstract

People with pharmacoresistant epilepsy are often candidates for resective epilepsy surgery. The presurgical evaluation for epilepsy aims to localize the epileptic network that initiates seizures (which should be disrupted or removed) and determine its spatial relationship to eloquent cortex (which should be preserved). Noninvasive functional imaging techniques play an increasingly important role in planning epilepsy surgery and assessing the feasibility, risks, and benefits of surgery. Magnetoencephalography (MEG) can be a very useful part of a comprehensive presurgical evaluation as it can model the sources of epileptiform activity and localize eloquent cortices within the same study. This review is designed to assist anyone in the field of neurology or related disciplines understand some methods and terminology relevant to clinical MEG. Every effort is made to present the information in nontechnical, approachable ways so that readers will come away with a basic understanding of how to interpret MEG findings when the reported data on one of their patients are presented to them.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1

Similar content being viewed by others

References

Papers of particular interest, published recently, have been highlighted as: •• Of major importances

  1. Cohen D. Magnetoencephalography: evidence of magnetic fields produced by alpha-rhythm currents. Science. 1968;161(3843):784–6.

    Article  PubMed  CAS  Google Scholar 

  2. Cohen D. Magnetoencephalography: detection of the brain's electrical activity with a superconducting magnetometer. Science. 1972;175(4022):664–6.

    Article  PubMed  CAS  Google Scholar 

  3. Hansen P, Kringleback M, Salmelin R. MEG: an introduction to methods. New York: Oxford University Press; 2010.

    Book  Google Scholar 

  4. Darvas F et al. Mapping human brain function with MEG and EEG: methods and validation. Neuroimage. 2004;23 Suppl 1:S289–99.

    Article  PubMed  Google Scholar 

  5. Papanicolaou AC. Clinical magnetoencephalography and magnetic source imaging. Cambridge: Cambridge University Press; 2009.

    Book  Google Scholar 

  6. Lin FH et al. Distributed current estimates using cortical orientation constraints. Hum Brain Mapp. 2006;27(1):1–13.

    Article  PubMed  Google Scholar 

  7. Pascual-Marqui RD. Standardized low-resolution brain electromagnetic tomography (sLORETA): technical details. Methods Find Exp Clin Pharmacol. 2002;24(Suppl D):5–12.

    PubMed  Google Scholar 

  8. Pascual-Marqui RD et al. Functional imaging with low-resolution brain electromagnetic tomography (LORETA): a review. Methods Find Exp Clin Pharmacol. 2002;24(Suppl C):91–5.

    PubMed  Google Scholar 

  9. Shiraishi H et al. Dynamic statistical parametric mapping for analyzing the magnetoencephalographic epileptiform activity in patients with epilepsy. J Child Neurol. 2005;20(4):363–9.

    Article  PubMed  Google Scholar 

  10. Robinson SE, Vrba J, et al. Functional neuroimaging by synthetic aperture magnetometry. In: In: Recent advances in biomagnetism. Sendai: Tohoku University Press; 1999. p. 302–5.

    Google Scholar 

  11. Van Veen BD et al. Localization of brain electrical activity via linearly constrained minimum variance spatial filtering. IEEE Trans Biomed Eng. 1997;44(9):867–80.

    Article  PubMed  Google Scholar 

  12. Rosenow F, Luders H. Presurgical evaluation of epilepsy. Brain. 2001;124(9):1683–700.

    Article  PubMed  CAS  Google Scholar 

  13. Tao JX et al. Intracranial EEG substrates of scalp EEG interictal spikes. Epilepsia. 2005;46(5):669–76.

    Article  PubMed  Google Scholar 

  14. Bagic AI. Disparities in clinical magnetoencephalography practice in the United States: a survey-based appraisal. J Clin Neurophysiol. 2011;28(4):341–7.

    Article  PubMed  Google Scholar 

  15. Tang L et al. Consistency of interictal and ictal onset localization using magnetoencephalography in patients with partial epilepsy. J Neurosurg. 2003;98(4):837–45.

    Article  PubMed  Google Scholar 

  16. Tilz C et al. Ictal onset localization of epileptic seizures by magnetoencephalography. Acta Neurol Scand. 2002;106(4):190–5.

    Article  PubMed  CAS  Google Scholar 

  17. Eliashiv DS et al. Ictal magnetic source imaging as a localizing tool in partial epilepsy. Neurology. 2002;59(10):1600–10.

    Article  PubMed  CAS  Google Scholar 

  18. Fujiwara H et al. Ictal MEG onset source localization compared to intracranial EEG and outcome: improved epilepsy presurgical evaluation in pediatrics. Epilepsy Res. 2012;99(3):214–24.

    Article  PubMed Central  PubMed  Google Scholar 

  19. Medvedovsky M et al. Sensitivity and specificity of seizure-onset zone estimation by ictal magnetoencephalography. Epilepsia. 2012;53(9):1649–57.

    Article  PubMed  Google Scholar 

  20. Ganslandt O et al. Functional neuronavigation with magnetoencephalography: outcome in 50 patients with lesions around the motor cortex. Neurosurg Focus. 1999;6(3):e3.

    PubMed  CAS  Google Scholar 

  21. Godey B et al. Neuromagnetic source localization of auditory evoked fields and intracerebral evoked potentials: a comparison of data in the same patients. Clin Neurophysiol. 2001;112(10):1850–9.

    Article  PubMed  CAS  Google Scholar 

  22. Grover KM et al. Retrospective review of MEG visual evoked hemifield responses prior to resection of temporo-parieto-occipital lesions. J Neurooncol. 2006;77(2):161–6.

    Article  PubMed  CAS  Google Scholar 

  23. Weinberg H, Cheyne D, Crisp D. Electroencephalographic and magnetoencephalographic studies of motor function. Adv Neurol. 1990;54:193–205.

    PubMed  CAS  Google Scholar 

  24. Sanders JA, Lewine JD, Orrison Jr WW. Comparison of primary motor cortex localization using functional magnetic resonance imaging and magnetoencephalography. Hum Brain Mapp. 1996;4(1):47–57.

    Article  PubMed  CAS  Google Scholar 

  25. Lin PT, Berger MS, Nagarajan SS. Motor field sensitivity for preoperative localization of motor cortex. J Neurosurg. 2006;105(4):588–94.

    Article  PubMed  Google Scholar 

  26. Gaetz W et al. Presurgical localization of primary motor cortex in pediatric patients with brain lesions by the use of spatially filtered magnetoencephalography. Neurosurgery. 2009;64(3 Suppl):ons177–85. discussion ons186.

    PubMed  Google Scholar 

  27. Nagarajan S et al. Preoperative localization of hand motor cortex by adaptive spatial filtering of magnetoencephalography data. J Neurosurg. 2008;109(2):228–37.

    Article  PubMed  Google Scholar 

  28. Ojemann GA, Dodrill CB. Predicting postoperative language and memory deficits after dominant hemisphere anterior temporal lobectomy by intraoperative stimulation mapping. Paper presented at: 50th annual meeting of the American Association of Neurological Surgeons; 1981; Boston.

  29. Wada J, Rasmussen T. Intracarotid injection of sodium amytal for the lateralization of cerebral speech dominance: experimental and clinical observations. J Neurosurg. 2007;106(6):1117–33.

    Article  PubMed  Google Scholar 

  30. Baxendale S, Thompson PJ, Duncan JS. The role of the Wada test in the surgical treatment of temporal lobe epilepsy: an international survey. Epilepsia. 2008;49(4):715–20. discussion 720-5.

    Article  PubMed  Google Scholar 

  31. Breier JI et al. Language dominance determined by magnetic source imaging: a comparison with the Wada procedure. Neurology. 1999;53(5):938–45.

    Article  PubMed  CAS  Google Scholar 

  32. Doss RC et al. Lateralizing language with magnetic source imaging: validation based on the Wada test. Epilepsia. 2009;50(10):2242–8.

    Article  PubMed  Google Scholar 

  33. Papanicolaou AC et al. Magnetocephalography: a noninvasive alternative to the Wada procedure. J Neurosurg. 2004;100(5):867–76.

    Article  PubMed  Google Scholar 

  34. Ota T et al. Refined analysis of complex language representations by non-invasive neuroimaging techniques. Br J Neurosurg. 2011;25(2):197–202.

    Article  PubMed  Google Scholar 

  35. Bowyer SM et al. Magnetoencephalographic localization of the basal temporal language area. Epilepsy Behav. 2005;6(2):229–34.

    Article  PubMed  Google Scholar 

  36. Lee SY et al. Assessment of language dominance by event-related oscillatory changes in an auditory language task: magnetoencephalography study. J Clin Neurophysiol. 2010;27(4):263–9.

    Article  PubMed  Google Scholar 

  37. McDonald CR et al. Distributed source modeling of language with magnetoencephalography: application to patients with intractable epilepsy. Epilepsia. 2009;50(10):2256–66.

    Article  PubMed Central  PubMed  Google Scholar 

  38. Kim JS, Chung CK. Language lateralization using MEG beta frequency desynchronization during auditory oddball stimulation with one-syllable words. Neuroimage. 2008;42(4):1499–507.

    Article  PubMed  Google Scholar 

  39. Hirata M et al. Language dominance and mapping based on neuromagnetic oscillatory changes: comparison with invasive procedures. J Neurosurg. 2010;112(3):528–38.

    Article  PubMed  Google Scholar 

  40. Taniguchi M et al. Movement-related desynchronization of the cerebral cortex studied with spatially filtered magnetoencephalography. Neuroimage. 2000;12(3):298–306.

    Article  PubMed  CAS  Google Scholar 

  41. Maestu F et al. Spanish language mapping using MEG: a validation study. Neuroimage. 2002;17(3):1579–86.

    Article  PubMed  Google Scholar 

  42. Merrifield WS et al. Hemispheric language dominance in magnetoencephalography: sensitivity, specificity, and data reduction techniques. Epilepsy Behav. 2007;10(1):120–8.

    Article  PubMed  Google Scholar 

  43. Janecek JK et al. Naming outcome prediction in patients with discordant Wada and fMRI language lateralization. Epilepsy Behav. 2013;27(2):399–403.

    Article  PubMed Central  PubMed  Google Scholar 

  44. Sabsevitz DS et al. Use of preoperative functional neuroimaging to predict language deficits from epilepsy surgery. Neurology. 2003;60(11):1788–92.

    Article  PubMed  CAS  Google Scholar 

  45. Wheless JW et al. A comparison of magnetoencephalography, MRI, and V-EEG in patients evaluated for epilepsy surgery. Epilepsia. 1999;40(7):931–41.

    Article  PubMed  CAS  Google Scholar 

  46. Holmes MD et al. Interictal, unifocal spikes in refractory extratemporal epilepsy predict ictal origin and postsurgical outcome. Clin Neurophysiol. 2000;111(10):1802–8.

    Article  PubMed  CAS  Google Scholar 

  47. Hufnagel A et al. Clinical relevance of quantified intracranial interictal spike activity in presurgical evaluation of epilepsy. Epilepsia. 2000;41(4):467–78.

    Article  PubMed  CAS  Google Scholar 

  48. Knake S et al. The value of multichannel MEG and EEG in the presurgical evaluation of 70 epilepsy patients. Epilepsy Res. 2006;69(1):80–6.

    Article  PubMed  CAS  Google Scholar 

  49. Knowlton RC et al. Functional imaging: II. Prediction of epilepsy surgery outcome. Ann Neurol. 2008;64(1):35–41.

    Article  PubMed  Google Scholar 

  50. Knowlton RC et al. Functional imaging: I. Relative predictive value of intracranial electroencephalography. Ann Neurol. 2008;64(1):25–34.

    Article  PubMed  Google Scholar 

  51. Paulini A et al. Lobar localization information in epilepsy patients: MEG—a useful tool in routine presurgical diagnosis. Epilepsy Res. 2007;76(2–3):124–30.

    Article  PubMed  Google Scholar 

  52. Sutherling WW et al. Influence of magnetic source imaging for planning intracranial EEG in epilepsy. Neurology. 2008;71(13):990–6.

    Article  PubMed Central  PubMed  CAS  Google Scholar 

  53. Funke ME et al. The role of magnetoencephalography in “nonlesional” epilepsy. Epilepsia. 2011;52 Suppl 4:10–4.

    Article  PubMed  Google Scholar 

  54. Moore KR et al. Magnetoencephalographically directed review of high-spatial-resolution surface-coil MR images improves lesion detection in patients with extratemporal epilepsy. Radiology. 2002;225(3):880–7.

    Article  PubMed  Google Scholar 

  55. Wilenius J et al. Interictal MEG reveals focal cortical dysplasias: special focus on patients with no visible MRI lesions. Epilepsy Res. 2013;105(3):337–48.

    Article  PubMed  Google Scholar 

  56. Knowlton RC et al. Effect of epilepsy magnetic source imaging on intracranial electrode placement. Ann Neurol. 2009;65(6):716–23.

    Article  PubMed Central  PubMed  Google Scholar 

  57. Frye RE, Rezaie R, Papanicolaou AC. Functional neuroimaging of language using magnetoencephalography. Phys Life Rev. 2009;6(1):1–10.

    Article  PubMed Central  PubMed  Google Scholar 

  58. D’Esposito M, Deouell LY, Gazzaley A. Alterations in the BOLD fMRI signal with ageing and disease: a challenge for neuroimaging. Nat Rev Neurosci. 2003;4(11):863–72.

    Article  PubMed  Google Scholar 

  59. Billingsley-Marshall RL et al. A comparison of functional MRI and magnetoencephalography for receptive language mapping. J Neurosci Methods. 2007;161(2):306–13.

    Article  PubMed  Google Scholar 

  60. Korvenoja A et al. Sensorimotor cortex localization: comparison of magnetoencephalography, functional MR imaging, and intraoperative cortical mapping. Radiology. 2006;241(1):213–22.

    Article  PubMed  Google Scholar 

  61. Morioka T et al. Comparison of magnetoencephalography, functional MRI, and motor evoked potentials in the localization of the sensory-motor cortex. Neurol Res. 1995;17(5):361–7.

    PubMed  CAS  Google Scholar 

  62. Baayen JC et al. Localization of slow wave activity in patients with tumor-associated epilepsy. Brain Topogr. 2003;16(2):85–93.

    Article  PubMed  Google Scholar 

  63. Gallen CC et al. Magnetic source imaging of abnormal low-frequency magnetic activity in presurgical evaluations of epilepsy. Epilepsia. 1997;38(4):452–60.

    Article  PubMed  CAS  Google Scholar 

  64. Zijlmans M et al. High-frequency oscillations as a new biomarker in epilepsy. Ann Neurol. 2012;71(2):169–78.

    Article  PubMed Central  PubMed  Google Scholar 

  65. Guggisberg AG et al. Fast oscillations associated with interictal spikes localize the epileptogenic zone in patients with partial epilepsy. Neuroimage. 2008;39(2):661–8.

    Article  PubMed Central  PubMed  Google Scholar 

  66. Rampp S et al. MEG correlates of epileptic high gamma oscillations in invasive EEG. Epilepsia. 2010;51(8):1638–42.

    Article  PubMed  Google Scholar 

  67. Xiang J et al. Frequency and spatial characteristics of high-frequency neuromagnetic signals in childhood epilepsy. Epileptic Disord. 2009;11(2):113–25.

    PubMed  Google Scholar 

  68. Bowyer SM et al. MEG localization of language-specific cortex utilizing MR-FOCUSS. Neurology. 2004;62(12):2247–55.

    Article  PubMed  CAS  Google Scholar 

  69. Findlay AM et al. Dynamics of hemispheric dominance for language assessed by magnetoencephalographic imaging. Ann Neurol. 2012;71(5):668–86.

    Article  PubMed Central  PubMed  Google Scholar 

  70. Tarapore PE et al. Magnetoencephalographic imaging of resting-state functional connectivity predicts postsurgical neurological outcome in brain gliomas. Neurosurgery. 2012;71(5):1012–22. This is a novel and very promising application of MEG functional connectivity to predict neurosurgical morbidity in tumor surgery. Functional connectivity is likely to become one of the next important methods of mapping cerebral function.

    Article  PubMed Central  PubMed  Google Scholar 

Download references

Compliance with Ethics Guidelines

Conflict of Interest

Christopher T. Anderson, Chad E. Carlson, Zhimin Li, and Manoj Raghavan declare that they have no conflict of interest.

Human and Animal Rights and Informed Consent

This article does not contain any studies with human or animal subjects performed by any of the authors.

Author information

Authors and Affiliations

  1. Department of Neurology, Medical College of Wisconsin, 9200 W. Wisconsin Ave, Milwaukee, WI, 53226, USA

    Christopher T. Anderson, Chad E. Carlson, Zhimin Li & Manoj Raghavan

Authors
  1. Christopher T. Anderson
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Chad E. Carlson
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Zhimin Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Manoj Raghavan
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Christopher T. Anderson.

Additional information

This article is part of Topical Collection on Epilepsy

Rights and permissions

Reprints and permissions

About this article

Cite this article

Anderson, C.T., Carlson, C.E., Li, Z. et al. Magnetoencephalography in the Preoperative Evaluation for Epilepsy Surgery. Curr Neurol Neurosci Rep 14, 446 (2014). https://doi.org/10.1007/s11910-014-0446-8

Download citation

  • Published:

  • DOI: https://doi.org/10.1007/s11910-014-0446-8

Keywords

Search

Navigation