MEG in Epilepsy and Pre-surgical Functional Mapping

  • Masaki IwasakiEmail author
  • Nobukazu Nakasato
Living reference work entry


Localization of epileptic discharges and pre-surgical functional brain mapping are the most common clinical applications of magnetoencephalography (MEG). According to the European Union-funded EPILEPSY project survey, performed in 2014, MEG source localization was used as a part of the pre-surgical diagnostic workup in 7 out of 25 centers (28%) (Mouthaan et al (2016) Epilepsia 57:770–776) indicating that the majority of “MEG centers” provide clinical services (Bagic et al. (2009) J Clin Neurophysiol 26:290–293). MEG is also utilized for pre-surgical functional brain mapping, that is, for accurate localization of “eloquent” cortex, used for planning surgical procedures near healthy functional brain areas. For example, somatosensory evoked fields to median nerve stimulation lead to an accurate, within a few millimeters, identification of the central sulcus, which may not be identifiable in anatomical MRI alone. In addition, MEG analysis of event-related potentials or event-related (de)synchronization in response to language tasks provides more than 80% sensitivity and specificity in language lateralization for intracarotid amobarbital procedures. Therefore, MEG is a noninvasive alternative for pre-surgical determination of the language-dominant hemisphere. In this chapter, the current status of clinical MEG in epilepsy and pre-surgical mapping is reviewed.


Magnetic source imaging Focal epilepsy Epilepsy surgery Epileptogenic zone Interictal spikes Ictal EEG Pre-surgical evaluation Intracranial EEG MRI FDG-PET Ictal SPECT Hippocampal sclerosis Cortical dysplasia Somatosensory evoked potential Event-related potential Event-related desynchronization Language dominance Intracarotid amobarbital procedure 


  1. Abou-Khalil B (2007) An update on determination of language dominance in screening for epilepsy surgery: the Wada test and newer noninvasive alternatives. Epilepsia 48:442–455 CrossRefGoogle Scholar
  2. Agirre-Arrizubieta Z, Huiskamp GJM, Ferrier CH et al (2009) Interictal magnetoencephalography and the irritative zone in the electrocorticogram. Brain 132:3060–3071CrossRefGoogle Scholar
  3. Almubarak S, Alexopoulos A, Von-Podewils F et al (2014) The correlation of magnetoencephalography to intracranial EEG in localizing the epileptogenic zone: a study of the surgical resection outcome. Epilepsy Res 108:1581–1590CrossRefGoogle Scholar
  4. Assaf BA, Karkar KM, Laxer KD et al (2003) Ictal magnetoencephalography in temporal and extratemporal lobe epilepsy. Epilepsia 44:1320–1327CrossRefGoogle Scholar
  5. Aydin Ü, Vorwerk J, Dümpelmann M et al (2015) Combined EEG/MEG can outperform single modality EEG or MEG source reconstruction in presurgical epilepsy diagnosis. PLoS One 10:e0118753CrossRefGoogle Scholar
  6. Bagić AI (2011) Disparities in clinical magnetoencephalography practice in the United States: a survey-based appraisal. J Clin Neurophysiol 28:341–347CrossRefGoogle Scholar
  7. Bagic A, Funke ME, Ebersole J (2009) American Clinical MEG Society (ACMEGS) position statement: the value of magnetoencephalography (MEG)/magnetic source imaging (MSI) in noninvasive presurgical evaluation of patients with medically intractable localization-related epilepsy. J Clin Neurophysiol 26:290–293CrossRefGoogle Scholar
  8. Bagić AI, Barkley GL, Rose DF, Ebersole JS (2011a) American clinical magnetoencephalography society clinical practice guideline 4: qualifications of MEG-EEG personnel. J Clin Neurophysiol 28:364–365CrossRefGoogle Scholar
  9. Bagić AI, Knowlton RC, Rose DF, Ebersole JS (2011b) American clinical magnetoencephalography society clinical practice guideline 3: MEG-EEG reporting. J Clin Neurophysiol 28:362–363CrossRefGoogle Scholar
  10. Bagić AI, Knowlton RC, Rose DF, Ebersole JS (2011c) American clinical magnetoencephalography society clinical practice guideline 1: recording and analysis of spontaneous cerebral activity. J Clin Neurophysiol 28:348–354Google Scholar
  11. Balakrishnan G, Grover KM, Mason K et al (2007) A retrospective analysis of the effect of general anesthetics on the successful detection of interictal epileptiform activity in magnetoencephalography. Anesth Analg 104:1493–1497CrossRefGoogle Scholar
  12. Barkley GL, Baumgartner C (2003) MEG and EEG in epilepsy. J Clin Neurophysiol 20:163–178CrossRefGoogle Scholar
  13. Barth DS (1993) The neurophysiological basis of epileptiform magnetic fields and localization of neocortical sources. J Clin Neurophysiol 10:99–107CrossRefGoogle Scholar
  14. Bast T, Ramantani G, Boppel T et al (2005) Source analysis of interictal spikes in polymicrogyria: loss of relevant cortical fissures requires simultaneous EEG to avoid MEG misinterpretation. NeuroImage 25:1232–1241CrossRefGoogle Scholar
  15. Bast T, Wright T, Boor R et al (2007) Combined EEG and MEG analysis of early somatosensory evoked activity in children and adolescents with focal epilepsies. Clin Neurophysiol 118:1721–1735CrossRefGoogle Scholar
  16. Baumgartner C, Pataraia E (2006) Revisiting the role of magnetoencephalography in epilepsy. Curr Opin Neurol 19:181–186CrossRefGoogle Scholar
  17. Berger MS, Cohen WA, Ojemann GA (1990) Correlation of motor cortex brain mapping data with magnetic resonance imaging. J Neurosurg 72:383–387CrossRefGoogle Scholar
  18. Bowyer SM, Mason K, Tepley N et al (2003) Magnetoencephalographic validation parameters for clinical evaluation of interictal epileptic activity. J Clin Neurophysiol 20:87–93CrossRefGoogle Scholar
  19. Bowyer SM, Moran JE, Mason KM et al (2004) MEG localization of language-specific cortex utilizing MR-FOCUSS. Neurology 62:2247–2255CrossRefGoogle Scholar
  20. Bowyer SM, Moran JE, Weiland BJ et al (2005) Language laterality determined by MEG mapping with MR-FOCUSS. Epilepsy Behav 6:235–241CrossRefGoogle Scholar
  21. Burch J, Marson A, Beyer F et al (2012) Dilemmas in the interpretation of diagnostic accuracy studies on presurgical workup for epilepsy surgery. Epilepsia 53:1294–1302CrossRefGoogle Scholar
  22. Burgess RC, Barkley GL, Bagić AI (2011a) Turning a new page in clinical magnetoencephalography: practicing according to the first clinical practice guidelines. J Clin Neurophysiol 28:336–340CrossRefGoogle Scholar
  23. Burgess RC, Funke ME, Bowyer SM et al (2011b) American clinical magnetoencephalography society clinical practice guideline 2: presurgical functional brain mapping using magnetic evoked fields. J Clin Neurophysiol 28:355–361CrossRefGoogle Scholar
  24. Carrette E, De Tiège X, Op De Beeck M et al (2011) Magnetoencephalography in epilepsy patients carrying a vagus nerve stimulator. Epilepsy Res 93:44–52CrossRefGoogle Scholar
  25. Chang EF, Nagarajan SS, Mantle M et al (2009) Magnetic source imaging for the surgical evaluation of electroencephalography-confirmed secondary bilateral synchrony in intractable epilepsy. J Neurosurg 111:1248–1256CrossRefGoogle Scholar
  26. Colon AJ, Ossenblok P, Nieuwenhuis L et al (2009) Use of routine MEG in the primary diagnostic process of epilepsy. J Clin Neurophysiol 26:326–332CrossRefGoogle Scholar
  27. De Jongh A, De Munck JC, Gonçalves SI, Ossenblok P (2005) Differences in MEG/EEG epileptic spike yields explained by regional differences in signal-to-noise ratios. J Clin Neurophysiol 22:153–158CrossRefGoogle Scholar
  28. De Tiège X, Carrette E, Legros B et al (2012) Clinical added value of magnetic source imaging in the presurgical evaluation of refractory focal epilepsy. J Neurol Neurosurg Psychiatry 83:417–423CrossRefGoogle Scholar
  29. Donahue D, Sanchez R, Hernandez A et al (2007) Preservation of a subcutaneous pocket for vagus nerve stimulation pulse generator during magnetoencephalography. Technical note. J Neurosurg 107:519–520Google Scholar
  30. Doss RC, Zhang W, Risse GL, Dickens DL (2009) Lateralizing language with magnetic source imaging: validation based on the Wada test. Epilepsia 50:2242–2248CrossRefGoogle Scholar
  31. Duncan JS (2010) Imaging in the surgical treatment of epilepsy. Nat Rev Neurol 6:537–550CrossRefGoogle Scholar
  32. Ebersole JS, Ebersole SM (2010) Combining MEG and EEG source modeling in epilepsy evaluations. J Clin Neurophysiol 27:360–371CrossRefGoogle Scholar
  33. Enatsu R, Mikuni N, Usui K et al (2008) Usefulness of MEG magnetometer for spike detection in patients with mesial temporal epileptic focus. NeuroImage 41:1206–1219CrossRefGoogle Scholar
  34. Englot DJ, Nagarajan SS, Imber BS et al (2015a) Epileptogenic zone localization using magnetoencephalography predicts seizure freedom in epilepsy surgery. Epilepsia 56:949–958CrossRefGoogle Scholar
  35. Englot DJ, Hinkley LB, Kort NS et al (2015b) Global and regional functional connectivity maps of neural oscillations in focal epilepsy. Brain 138:2249–2262CrossRefGoogle Scholar
  36. Evans LT, Morse R, Roberts DW (2012) Epilepsy surgery in tuberous sclerosis: a review. Neurosurg Focus 32:E5CrossRefGoogle Scholar
  37. Fernandes JM, Da Silva AM, Huiskamp G et al (2005) What does an epileptiform spike look like in MEG? Comparison between coincident EEG and MEG spikes. J Clin Neurophysiol 22:68–73CrossRefGoogle Scholar
  38. Findlay AM, Ambrose JB, Cahn-Weiner DA et al (2012) Dynamics of hemispheric dominance for language assessed by magnetoencephalographic imaging. Ann Neurol 71:668–686CrossRefGoogle Scholar
  39. Fischer MJM, Scheler G, Stefan H (2005) Utilization of magnetoencephalography results to obtain favourable outcomes in epilepsy surgery. Brain 128:153–157CrossRefGoogle Scholar
  40. Fisher RS, Van Emde Boas W, Blume W et al (2005) Epileptic seizures and epilepsy: definitions proposed by the International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE). Epilepsia 46:470–472CrossRefGoogle Scholar
  41. Fujiwara H, Greiner HM, Hemasilpin N et al (2012) Ictal MEG onset source localization compared to intracranial EEG and outcome: improved epilepsy presurgical evaluation in pediatrics. Epilepsy Res 99:214–224CrossRefGoogle Scholar
  42. Hashizume A, Iida K, Shirozu H et al (2007) Gradient magnetic-field topography for dynamic changes of epileptic discharges. Brain Res 1144:175–179CrossRefGoogle Scholar
  43. Heers M, Rampp S, Kaltenhäuser M et al (2010a) Detection of epileptic spikes by magnetoencephalography and electroencephalography after sleep deprivation. Seizure 19:397–403CrossRefGoogle Scholar
  44. Heers M, Rampp S, Kaltenhäuser M et al (2010b) Monofocal MEG in lesional TLE: does video EEG monitoring add crucial information? Epilepsy Res 92:54–62CrossRefGoogle Scholar
  45. Hillebrand A, Barnes GR (2002) A quantitative assessment of the sensitivity of whole-head MEG to activity in the adult human cortex. NeuroImage 16:638–650CrossRefGoogle Scholar
  46. Hirata M, Goto T, Barnes G et al (2010) Language dominance and mapping based on neuromagnetic oscillatory changes: comparison with invasive procedures. J Neurosurg 112:528–538CrossRefGoogle Scholar
  47. Huiskamp G, Agirre-Arrizubieta Z, Leijten F (2010) Regional differences in the sensitivity of MEG for interictal spikes in epilepsy. Brain Topogr 23:159–164CrossRefGoogle Scholar
  48. Iida K, Otsubo H, Matsumoto Y et al (2005a) Characterizing magnetic spike sources by using magnetoencephalography-guided neuronavigation in epilepsy surgery in pediatric patients. J Neurosurg 102:187–196CrossRefGoogle Scholar
  49. Iida K, Otsubo H, Mohamed IS et al (2005b) Characterizing magnetoencephalographic spike sources in children with tuberous sclerosis complex. Epilepsia 46:1510–1517. CrossRefGoogle Scholar
  50. Ishitobi M, Nakasato N, Yamamoto K, Iinuma K (2005) Opercular to interhemispheric source distribution of benign rolandic spikes of childhood. Neuroimage 25:417–423CrossRefGoogle Scholar
  51. Iwasaki M, Burgess RC (2008) Magnetoencephalography in the evaluation of the irritative zone. In: Lüders HO (ed) Textbook of epilepsy surgery. Informa Healthcare, London, pp 537–543CrossRefGoogle Scholar
  52. Iwasaki M, Nakasato N, Shamoto H et al (2002) Surgical implications of neuromagnetic spike localization in temporal lobe epilepsy. Epilepsia 43:415–424CrossRefGoogle Scholar
  53. Iwasaki M, Nakasato N, Shamoto H, Yoshimoto T (2003) Focal magnetoencephalographic spikes in the superior temporal plane undetected by scalp EEG. J Clin Neurosci 10:236–238CrossRefGoogle Scholar
  54. Iwasaki M, Pestana E, Burgess RC et al (2005) Detection of epileptiform activity by human interpreters: blinded comparison between electroencephalography and magnetoencephalography. Epilepsia 46:59–68CrossRefGoogle Scholar
  55. Jansen FE, Huiskamp G, Van Huffelen AC et al (2006) Identification of the epileptogenic tuber in patients with tuberous sclerosis: a comparison of high-resolution EEG and MEG. Epilepsia 47:108–114CrossRefGoogle Scholar
  56. Jung J, Bouet R, Delpuech C et al (2013) The value of magnetoencephalography for seizure-onset zone localization in magnetic resonance imaging-negative partial epilepsy. Brain 136:3176–3186CrossRefGoogle Scholar
  57. Kagawa K, Iida K, Hashizume A et al (2016) Magnetoencephalography using gradient magnetic field topography (GMFT) can predict successful anterior corpus callosotomy in patients with drop attacks. Clin Neurophysiol 127:221–229CrossRefGoogle Scholar
  58. Kaiboriboon K, Nagarajan S, Mantle M, Kirsch HE (2010) Interictal MEG/MSI in intractable mesial temporal lobe epilepsy: spike yield and characterization. Clin Neurophysiol 121:325–331CrossRefGoogle Scholar
  59. Kakisaka Y, Nakasato N, Haginoya K et al (2009) Sensorimotor seizures of pediatric onset with unusual posteriorly oriented rolandic spikes. Epilepsy Res 84:153–158CrossRefGoogle Scholar
  60. Kakisaka Y, Alexopoulos AV, Gupta A et al (2010) Generalized 3-Hz spike-and-wave complexes emanating from focal epileptic activity in pediatric patients. Epilepsy Behav 20:103–106CrossRefGoogle Scholar
  61. Kakisaka Y, Gupta A, Wang ZI et al (2011a) Different cortical involvement pattern of generalized and localized spasms: a magnetoencephalography study. Epilepsy Behav 22:599–601CrossRefGoogle Scholar
  62. Kakisaka Y, Iwasaki M, Haginoya K et al (2011b) Somatotopic distribution of peri-rolandic spikes may predict prognosis in pediatric-onset epilepsy with sensorimotor seizures. Clin Neurophysiol 122:869–873CrossRefGoogle Scholar
  63. Kakisaka Y, Iwasaki M, Alexopoulos AV et al (2012a) Magnetoencephalography in fronto-parietal opercular epilepsy. Epilepsy Res 102:71–77CrossRefGoogle Scholar
  64. Kakisaka Y, Wang ZI, Mosher JC et al (2012b) Clinical evidence for the utility of movement compensation algorithm in magnetoencephalography: successful localization during focal seizure. Epilepsy Res 101:191–196CrossRefGoogle Scholar
  65. Kakisaka Y, Wang ZI, Mosher JC et al (2012d) Magnetoencephalography’s higher sensitivity to epileptic spikes may elucidate the profile of electroencephalographically negative epileptic seizures. Epilepsy Behav 23:171–173CrossRefGoogle Scholar
  66. Kakisaka Y, Mosher JC, Wang ZI et al (2013) Utility of temporally-extended signal space separation algorithm for magnetic noise from vagal nerve stimulators. Clin Neurophysiol 124:1277–1282CrossRefGoogle Scholar
  67. Kawamura T, Nakasato N, Seki K et al (1996) Neuromagnetic evidence of pre- and post-central cortical sources of somatosensory evoked responses. Electroencephalogr Clin Neurophysiol 100:44–50CrossRefGoogle Scholar
  68. Kirsch HE, Mantle M, Nagarajan SS (2007a) Concordance between routine interictal magnetoencephalography and simultaneous scalp electroencephalography in a sample of patients with epilepsy. J Clin Neurophysiol 24:215–231CrossRefGoogle Scholar
  69. Kirsch HE, Zhu Z, Honma S et al (2007b) Predicting the location of mouth motor cortex in patients with brain tumors by using somatosensory evoked field measurements. J Neurosurg 107:481–487CrossRefGoogle Scholar
  70. Knake S, Halgren E, Shiraishi H et al (2006) The value of multichannel MEG and EEG in the presurgical evaluation of 70 epilepsy patients. Epilepsy Res 69:80–86CrossRefGoogle Scholar
  71. Knowlton RC, Elgavish R, Howell J et al (2006) Magnetic source imaging versus intracranial electroencephalogram in epilepsy surgery: a prospective study. Ann Neurol 59:835–842CrossRefGoogle Scholar
  72. Knowlton RC, Razdan SN, Limdi N et al (2009) Effect of epilepsy magnetic source imaging on intracranial electrode placement. Ann Neurol 65:716–723CrossRefGoogle Scholar
  73. König MW, Mahmoud MA, Fujiwara H et al (2009) Influence of anesthetic management on quality of magnetoencephalography scan data in pediatric patients: a case series. Paediatr Anaesth 19:507–512CrossRefGoogle Scholar
  74. Krishnan B, Vlachos I, Wang ZI et al (2015) Epileptic focus localization based on resting state interictal MEG recordings is feasible irrespective of the presence or absence of spikes. Clin Neurophysiol 126:667–674CrossRefGoogle Scholar
  75. Kubota Y, Otsuki T, Kaneko Y et al (2007) Delayed N100m latency in focal epilepsy associated with spike dipoles at the primary auditory cortex. J Clin Neurophysiol 24:263–270CrossRefGoogle Scholar
  76. Lau M, Yam D, Burneo JG (2008) A systematic review on MEG and its use in the presurgical evaluation of localization-related epilepsy. Epilepsy Res 79:97–104CrossRefGoogle Scholar
  77. Lee D, Sawrie SM, Simos PG et al (2006) Reliability of language mapping with magnetic source imaging in epilepsy surgery candidates. Epilepsy Behav 8:742–749CrossRefGoogle Scholar
  78. Lee JW, Tanaka N, Shiraishi H et al (2010a) Evaluation of postoperative sharp waveforms through EEG and magnetoencephalography. J Clin Neurophysiol 27:7–11CrossRefGoogle Scholar
  79. Lee S-Y, Kim JS, Chung CK et al (2010b) Assessment of language dominance by event-related oscillatory changes in an auditory language task: magnetoencephalography study. J Clin Neurophysiol 27:263–269CrossRefGoogle Scholar
  80. Leijten FSS, Huiskamp G (2008) Interictal electromagnetic source imaging in focal epilepsy: practices, results and recommendations. Curr Opin Neurol 21:437–445CrossRefGoogle Scholar
  81. Leijten FSS, Huiskamp GM, Hilgersom I, Van Huffelen AC (2003) High-resolution source imaging in mesiotemporal lobe epilepsy: a comparison between MEG and simultaneous EEG. J Clin Neurophysiol 20:227–238CrossRefGoogle Scholar
  82. Lin YY, Shih YH, Hsieh JC et al (2003) Magnetoencephalographic yield of interictal spikes in temporal lobe epilepsy. Comparison with scalp EEG recordings. Neuroimage 19:1115–1126CrossRefGoogle Scholar
  83. Lüders HO, Engel JJ, Munari C (1993) General principles. In: Engel JJ (ed) Surgical treatment of epilepsy, 2nd edn. Raven Press, New York, pp 137–153Google Scholar
  84. Mäkelä JP, Forss N, Jääskeläinen J et al (2006) Magnetoencephalography in neurosurgery. Neurosurgery 59:493–510CrossRefGoogle Scholar
  85. Malmivuo J, Suihko V, Eskola H (1997) Sensitivity distributions of EEG and MEG measurements. IEEE Trans Biomed Eng 44:196–208CrossRefGoogle Scholar
  86. McDonald CR, Thesen T, Hagler DJ et al (2009) Distributed source modeling of language with magnetoencephalography: application to patients with intractable epilepsy. Epilepsia 50:2256–2266CrossRefGoogle Scholar
  87. Medvedovsky M, Taulu S, Gaily E et al (2012) Sensitivity and specificity of seizure-onset zone estimation by ictal magnetoencephalography. Epilepsia 53:1649–1657CrossRefGoogle Scholar
  88. Merrifield WS, Simos PG, Papanicolaou AC et al (2007) Hemispheric language dominance in magnetoencephalography: sensitivity, specificity, and data reduction techniques. Epilepsy Behav 10:120–128CrossRefGoogle Scholar
  89. Mohamed IS, Otsubo H, Ochi A et al (2007) Utility of magnetoencephalography in the evaluation of recurrent seizures after epilepsy surgery. Epilepsia 48:2150–2159CrossRefGoogle Scholar
  90. Mohamed IS, Gibbs SA, Robert M et al (2013) The utility of magnetoencephalography in the presurgical evaluation of refractory insular epilepsy. Epilepsia 54:1950–1959CrossRefGoogle Scholar
  91. Mouthaan BE, Rados M, Barsi P et al (2016) Current use of imaging and electromagnetic source localization procedures in epilepsy surgery centers across Europe. Epilepsia 57:770–776CrossRefGoogle Scholar
  92. Mu J, Rampp S, Carrette E et al (2014) Clinical relevance of source location in frontal lobe epilepsy and prediction of postoperative long-term outcome. Seizure 23:553–559CrossRefGoogle Scholar
  93. Murakami H, Wang ZI, Marashly A et al (2016) Correlating magnetoencephalography to stereo-electroencephalography in patients undergoing epilepsy surgery. Brain 139:2935–2947CrossRefGoogle Scholar
  94. Nagamatsu K, Nakasato N, Hatanaka K et al (2001) Neuromagnetic localization of N15, the initial cortical response to lip stimulus. Neuroreport 12:1–5CrossRefGoogle Scholar
  95. Nakajima M, Widjaja E, Baba S et al (2016) Remote MEG dipoles in focal cortical dysplasia at bottom of sulcus. Epilepsia 57:1169–1178CrossRefGoogle Scholar
  96. Nakasato N, Yoshimoto T (2000) Somatosensory, auditory, and visual evoked magnetic fields in patients with brain diseases. J Clin Neurophysiol 17:201–211CrossRefGoogle Scholar
  97. Nakasato N, Kumabe T, Kanno A et al (1997) Neuromagnetic evaluation of cortical auditory function in patients with temporal lobe tumors. J Neurosurg 86:610–618CrossRefGoogle Scholar
  98. Nissen IA, Stam CJ, Reijneveld JC et al (2017) Identifying the epileptogenic zone in interictal resting-state MEG source-space networks. Epilepsia 58:137–148CrossRefGoogle Scholar
  99. Oishi M, Kameyama S, Masuda H et al (2006) Single and multiple clusters of magnetoencephalographic dipoles in neocortical epilepsy: significance in characterizing the epileptogenic zone. Epilepsia 47:355–364CrossRefGoogle Scholar
  100. Ossadtchi A, Baillet S, Mosher JC et al (2004) Automated interictal spike detection and source localization in magnetoencephalography using independent components analysis and spatio-temporal clustering. Clin Neurophysiol 115:508–522CrossRefGoogle Scholar
  101. Ossenblok P, De Munck JC, Colon A et al (2007) Magnetoencephalography is more successful for screening and localizing frontal lobe epilepsy than electroencephalography. Epilepsia 48:2139–2149CrossRefGoogle Scholar
  102. Papanicolaou AC, Simos PG, Castillo EM et al (2004) Magnetocephalography: a noninvasive alternative to the Wada procedure. J Neurosurg 100:867–876CrossRefGoogle Scholar
  103. Park H-M, Nakasato N, Iwasaki M et al (2004) Comparison of magnetoencephalographic spikes with and without concurrent electroencephalographic spikes in extratemporal epilepsy. Tohoku J Exp Med 203:165–174CrossRefGoogle Scholar
  104. Pataraia E, Lindinger G, Deecke L et al (2005) Combined MEG/EEG analysis of the interictal spike complex in mesial temporal lobe epilepsy. NeuroImage 24:607–614CrossRefGoogle Scholar
  105. Pellegrino G, Hedrich T, Chowdhury RA et al (2018) Clinical yield of magnetoencephalography distributed source imaging in epilepsy: a comparison with equivalent current dipole method. Hum Brain Mapp 39:218–231CrossRefGoogle Scholar
  106. Pelletier I, Sauerwein HC, Lepore F et al (2007) Non-invasive alternatives to the Wada test in the presurgical evaluation of language and memory functions in epilepsy patients. Epileptic Disord 9:111–126Google Scholar
  107. Perkins FF, Breier J, McManis MH et al (2008) Benign rolandic epilepsy – perhaps not so benign: use of magnetic source imaging as a predictor of outcome. J Child Neurol 23:389–393CrossRefGoogle Scholar
  108. Pirmoradi M, Béland R, Nguyen DK et al (2010) Language tasks used for the presurgical assessment of epileptic patients with MEG. Epileptic Disord 12:97–108Google Scholar
  109. Ramachandrannair R, Otsubo H, Shroff MM et al (2007) MEG predicts outcome following surgery for intractable epilepsy in children with normal or nonfocal MRI findings. Epilepsia 48:149–157CrossRefGoogle Scholar
  110. Ramachandrannair R, Ochi A, Imai K et al (2008) Epileptic spasms in older pediatric patients: MEG and ictal high-frequency oscillations suggest focal-onset seizures in a subset of epileptic spasms. Epilepsy Res 78:216–224CrossRefGoogle Scholar
  111. Ramantani G, Boor R, Paetau R et al (2006) MEG versus EEG: influence of background activity on interictal spike detection. J Clin Neurophysiol 23:498–508CrossRefGoogle Scholar
  112. Ramanujam B, Bharti K, Viswanathan V et al (2017) Can ictal-MEG obviate the need for phase II monitoring in people with drug-refractory epilepsy? A prospective observational study. Seizure 45:17–23CrossRefGoogle Scholar
  113. Rodin E, Funke M, Berg P, Matsuo F (2004) Magnetoencephalographic spikes not detected by conventional electroencephalography. Clin Neurophysiol 115:2041–2047CrossRefGoogle Scholar
  114. Sakurai K, Tanaka N, Kamada K et al (2007) Magnetoencephalographic studies of focal epileptic activity in three patients with epilepsy suggestive of Lennox-Gastaut syndrome. Epileptic Disord 9:158–163Google Scholar
  115. Sakurai K, Takeda Y, Tanaka N et al (2010) Generalized spike-wave discharges involve a default mode network in patients with juvenile absence epilepsy: a MEG study. Epilepsy Res 89:176–184CrossRefGoogle Scholar
  116. Salayev KA, Nakasato N, Ishitobi M et al (2006) Spike orientation may predict epileptogenic side across cerebral sulci containing the estimated equivalent dipole. Clin Neurophysiol 117:1836–1843CrossRefGoogle Scholar
  117. Salmelin R, Hari R (1994) Characterization of spontaneous MEG rhythms in healthy adults. Electroencephalogr Clin Neurophysiol 91:237–248CrossRefGoogle Scholar
  118. Schneider F, Alexopoulos AV, Wang Z et al (2012) Magnetic source imaging in non-lesional neocortical epilepsy: additional value and comparison with ICEEG. Epilepsy Behav 24:234–240CrossRefGoogle Scholar
  119. Schneider F, Irene Wang Z, Alexopoulos AV et al (2013) Magnetic source imaging and ictal SPECT in MRI-negative neocortical epilepsies: additional value and comparison with intracranial EEG. Epilepsia 54:359–369CrossRefGoogle Scholar
  120. Schwartz ES, Edgar JC, Gaetz WC, Roberts TPL (2010) Magnetoencephalography. Pediatr Radiol 40:50–58CrossRefGoogle Scholar
  121. Seo JH, Holland K, Rose D et al (2011) Multimodality imaging in the surgical treatment of children with nonlesional epilepsy. Neurology 76:41–48CrossRefGoogle Scholar
  122. Shibasaki H, Ikeda A, Nagamine T (2007) Use of magnetoencephalography in the presurgical evaluation of epilepsy patients. Clin Neurophysiol 118:1438–1448CrossRefGoogle Scholar
  123. Shiraishi H, Ahlfors SP, Stufflebeam SM et al (2005) Application of magnetoencephalography in epilepsy patients with widespread spike or slow-wave activity. Epilepsia 46:1264–1272CrossRefGoogle Scholar
  124. Shiraishi H, Ahlfors SP, Stufflebeam SM et al (2011) Comparison of three methods for localizing interictal epileptiform discharges with magnetoencephalography. J Clin Neurophysiol 28:431–440Google Scholar
  125. Shirozu H, Iida K, Hashizume A et al (2010) Gradient magnetic-field topography reflecting cortical activities of neocortical epilepsy spikes. Epilepsy Res 90:121–131CrossRefGoogle Scholar
  126. Shirozu H, Hashizume A, Masuda H et al (2017) Analysis of ictal magnetoencephalography using gradient magnetic-field topography (GMFT) in patients with neocortical epilepsy. Clin Neurophysiol 128:1504–1512CrossRefGoogle Scholar
  127. Slater JD, Khan S, Li Z, Castillo E (2012) Characterization of interictal epileptiform discharges with time-resolved cortical current maps using the helmholtz-hodge decomposition. Front Neurol 3:138CrossRefGoogle Scholar
  128. Song T, Cui L, Gaa K et al (2009) Signal space separation algorithm and its application on suppressing artifacts caused by vagus nerve stimulation for magnetoencephalography recordings. J Clin Neurophysiol 26:392–400CrossRefGoogle Scholar
  129. Stefan H, Trinka E (2017) Magnetoencephalography (MEG): past, current and future perspectives for improved differentiation and treatment of epilepsies. Seizure 44:121–124CrossRefGoogle Scholar
  130. Stefan H, Hummel C, Scheler G et al (2003) Magnetic brain source imaging of focal epileptic activity: a synopsis of 455 cases. Brain 126:2396–2405CrossRefGoogle Scholar
  131. Stefan H, Paulini-Ruf A, Hopfengärtner R, Rampp S (2009) Network characteristics of idiopathic generalized epilepsies in combined MEG/EEG. Epilepsy Res 85:187–198CrossRefGoogle Scholar
  132. Stefan H, Heers M, Schmitt HJ et al (2010) Increased spike frequency during general anesthesia with etomidate for magnetoencephalography in patients with focal epilepsies. Clin Neurophysiol 121:1220–1226CrossRefGoogle Scholar
  133. Stefan H, Rampp S, Knowlton RC (2011a) Magnetoencephalography adds to the surgical evaluation process. Epilepsy Behav 20:172–177CrossRefGoogle Scholar
  134. Stefan H, Wu X, Buchfelder M et al (2011b) MEG in frontal lobe epilepsies: localization and postoperative outcome. Epilepsia 52:2233–2238CrossRefGoogle Scholar
  135. Stephen JM, Ranken DM, Aine CJ et al (2005) Differentiability of simulated MEG hippocampal, medial temporal and neocortical temporal epileptic spike activity. J Clin Neurophysiol 22:388–401Google Scholar
  136. Stufflebeam SM, Tanaka N, Ahlfors SP (2009) Clinical applications of magnetoencephalography. Hum Brain Mapp 30:1813–1823CrossRefGoogle Scholar
  137. Sutherling WW, Mamelak AN, Thyerlei D et al (2008) Influence of magnetic source imaging for planning intracranial EEG in epilepsy. Neurology 71:990–996CrossRefGoogle Scholar
  138. Szmuk P, Kee S, Pivalizza EG et al (2003) Anaesthesia for magnetoencephalography in children with intractable seizures. Paediatr Anaesth 13:811–817CrossRefGoogle Scholar
  139. Tanaka N, Cole AJ, Von Pechmann D et al (2009a) Dynamic statistical parametric mapping for analyzing ictal magnetoencephalographic spikes in patients with intractable frontal lobe epilepsy. Epilepsy Res 85:279–286CrossRefGoogle Scholar
  140. Tanaka N, Thiele EA, Madsen JR et al (2009b) Magnetoencephalographic analysis in patients with vagus nerve stimulator. Pediatr Neurol 41:383–387CrossRefGoogle Scholar
  141. Tanaka N, Liu H, Reinsberger C et al (2013) Language lateralization represented by spatiotemporal mapping of magnetoencephalography. AJNR Am J Neuroradiol 34:558–563CrossRefGoogle Scholar
  142. Uda T, Tsuyuguchi N, Okumura E et al (2012) sLORETA-qm for interictal MEG epileptic spike analysis: comparison of location and quantity with equivalent dipole estimation. Clin Neurophysiol 123:1496–1501CrossRefGoogle Scholar
  143. Usui K, Ikeda A, Nagamine T et al (2009) Abnormal auditory cortex with giant N100m signal in patients with autosomal dominant lateral temporal lobe epilepsy. Clin Neurophysiol 120:1923–1926CrossRefGoogle Scholar
  144. Van Poppel M, Wheless JW, Clarke DF et al (2012) Passive language mapping with magnetoencephalography in pediatric patients with epilepsy. J Neurosurg Pediatr 10:96–102CrossRefGoogle Scholar
  145. Wang ZI, Alexopoulos AV, Jones SE et al (2014) Linking MRI postprocessing with magnetic source imaging in MRI-negative epilepsy. Ann Neurol 75:759–770CrossRefGoogle Scholar
  146. Wennberg R, Valiante T, Cheyne D (2011) EEG and MEG in mesial temporal lobe epilepsy: where do the spikes really come from? Clin Neurophysiol 122:1295–1313CrossRefGoogle Scholar
  147. Westmijse I, Ossenblok P, Gunning B, Van Luijtelaar G (2009) Onset and propagation of spike and slow wave discharges in human absence epilepsy: a MEG study. Epilepsia 50:2538–2548CrossRefGoogle Scholar
  148. Widjaja E, Otsubo H, Raybaud C et al (2008) Characteristics of MEG and MRI between Taylor’s focal cortical dysplasia (type II) and other cortical dysplasia: surgical outcome after complete resection of MEG spike source and MR lesion in pediatric cortical dysplasia. Epilepsy Res 82:147–155CrossRefGoogle Scholar
  149. Widjaja E, Zarei Mahmoodabadi S, Otsubo H et al (2009) Subcortical alterations in tissue microstructure adjacent to focal cortical dysplasia: detection at diffusion-tensor MR imaging by using magnetoencephalographic dipole cluster localization. Radiology 251:206–215CrossRefGoogle Scholar
  150. World Health Organization (2009) Epilepsy fact sheet. Accessed 16 Feb 2013
  151. Wu JY, Sutherling WW, Koh S et al (2006) Magnetic source imaging localizes epileptogenic zone in children with tuberous sclerosis complex. Neurology 66:1270–1272CrossRefGoogle Scholar
  152. Wu X-T, Rampp S, Buchfelder M et al (2013) Interictal magnetoencephalography used in magnetic resonance imaging-negative patients with epilepsy. Acta Neurol Scand 127:274–280CrossRefGoogle Scholar
  153. Yoshinaga H, Kobayashi K, Hoshida T et al (2008) Magnetoencephalogram in a postoperative case with a large skull defect. Pediatr Neurol 39:48–51CrossRefGoogle Scholar
  154. Yu HY, Nakasato N, Iwasaki M et al (2004) Neuromagnetic separation of secondarily bilateral synchronized spike foci: report of three cases. J Clin Neurosci 11:644–648CrossRefGoogle Scholar
  155. Zhang R, Wu T, Wang Y et al (2011) Interictal magnetoencephalographic findings related with surgical outcomes in lesional and nonlesional neocortical epilepsy. Seizure 20:692–700CrossRefGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Department of NeurosurgeryNational Center Hospital, National Center of Neurology and PsychiatryTokyoJapan
  2. 2.Department of EpileptologyTohoku University Graduate School of MedicineSendaiJapan

Section editors and affiliations

  • Nobukazu Nakasato
    • 1
  1. 1.Department of EpileptologyTohoku University Graduate School of MedicineMiyagiJapan

Personalised recommendations