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Zeitschrift für Epileptologie

, Volume 31, Issue 3, pp 197–202 | Cite as

Ictal EEG source imaging

  • Sándor Beniczky
  • Praveen Sharma
Leitthema
  • 49 Downloads

Abstract

Background

Ictal electroencephalogram (EEG) source imaging has both advantages and disadvantages compared with source imaging of interictal epileptiform discharges. Ictal source imaging estimates the seizure onset zone directly. However, the rapid propagation of the ictal activity and the low signal-to-noise ratio impose additional challenges on ictal source imaging. Several methods have been developed to circumvent these challenges.

Objectives

To summarize and explain in plain terms the methods of ictal EEG source imaging and to review the published evidence on its accuracy.

Materials and methods

We systematically searched Medline for studies of ictal EEG source imaging. In addition, we summarize our clinical experience with ictal EEG source imaging and we present illustrative examples for the analysis process.

Results

Pooled data from 77 operated patients, from four clinical studies, showed that ictal EEG source imaging had a sensitivity of 83.3% (95% confidence interval: 69.8–92.5%) and specificity of 72.4% (95% confidence interval: 52.8–87.3%).

Conclusion

Ictal EEG source imaging is accurate and it should be added to the multimodal presurgical evaluation of patients with drug-resistant focal epilepsy.

Keywords

Epilepsy Meta-analysis Presurgical evaluation Seizure Source analysis 

Quellenanalyse iktaler EEG-Daten

Zusammenfassung

Hintergrund

Die Quellenanalyse iktaler EEG-Daten hat Vor- und Nachteile gegenüber der Analyse interiktaler epilepsietypischer Muster. Die iktale Quellenanalyse zielt darauf, die Lage der Anfallsursprungszone direkt zu berechnen. Jedoch stellen die schnelle Propagation iktaler Aktivität, sowie ein niedriges Signal-Rausch-Verhältnis zusätzliche Probleme dar. Verschiedene Methoden wurden als Lösungsansätze entwickelt.

Ziel der Arbeit

Zielsetzung der Arbeit ist eine Zusammenfassung der Methoden der Quellenanalyse iktaler EEG-Daten, eine Erläuterung der grundlegenden Funktionsweise, sowie ein Überblick über die publizierte Evidenz zur Genauigkeit.

Material und Methoden

Die Datenbank Medline wurde systematisch nach Studien zur iktalen EEG-Quellenanalyse durchsucht. Darüber hinaus fassen die Autoren ihre klinische Erfahrung zum Thema zusammen und zeigen illustrative Beispiele für den Auswertungsablauf.

Ergebnisse

Gepoolte Daten von 77 operierten Patienten aus 4 klinischen Studien liefern für die iktale Quellenanalyse eine Sensitivität von 83,3 % (95%-Konfidenzintervall, 95%-KI: 69,8–92,5 %) und eine Spezifität von 72,4 % (95%-KI: 52,8–87,3 %.)

Schlussfolgerung

Die Quellenanalyse iktaler EEG-Daten weist eine hohe Genauigkeit auf und sollte zusätzlich zur multimodalen prächirurgischen Evaluation von Patienten mit pharmakoresistenten fokalen Epilepsien durchgeführt werden..

Schlüsselwörter

Epilepsie Metaanalyse Prächirurgische Evaluation Anfall Quellenanalyse 

Notes

Acknowledgements

The study was supported by the D.B. Gupta research fellowship of the European Academy of Neurology.

Compliance with ethical guidelines

Conflict of interest

S. Beniczky and P. Sharma declare that they have no competing interests.

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

References

  1. 1.
    Alarcon G, Guy CN, Binnie CD, Walker SR, Elwes RDC, Polkey CE (1994) Intracerebral propagation of interictal activity in partial epilepsy: implications for source localisation. J Neurol Neurosurg Psychiatr 57:435–449CrossRefGoogle Scholar
  2. 2.
    Assaf B, Ebersole J (1997) Continuous source imaging of scalp ictal rhythms in temporal lobe epilepsy. Epilepsia 38:1114–1123CrossRefPubMedGoogle Scholar
  3. 3.
    Assaf BA, Ebersole JS (1999) Visual and quantitative ictal EEG predictors of outcome after temporal lobectomy. Epilepsia 40:52–61CrossRefPubMedGoogle Scholar
  4. 4.
    Beniczky S, Lantz G, Rosenzweig I, Åkeson P, Pedersen B, Pinborg LH, Ziebell M, Jespersen B, Fuglsang-Frederiksen A (2013) Source localization of rhythmic ictal EEG activity: a study of diagnostic accuracy following STARD criteria. Epilepsia 54:1743–1752CrossRefPubMedGoogle Scholar
  5. 5.
    Beniczky S, Oturai PS, Alving J, Sabers A, Herning M, Fabricius M (2006) Source analysis of epileptic discharges using multiple signal classification analysis. Neuroreport 17:1283–1287CrossRefPubMedGoogle Scholar
  6. 6.
    Beniczky S, Rosenzweig I, Scherg M, Jordanov T, Lanfer B, Lantz G, Larsson PG (2016) Ictal EEG source imaging in presurgical evaluation: high agreement between analysis methods. Seizure 43:1–5CrossRefPubMedPubMedCentralGoogle Scholar
  7. 7.
    Blanke O, Lantz G, Seeck M, Spinelli L, Grave de Peralta R, Thut G (2000) Temporal and spatial determination of EEG seizure onset in the frequency domain. Clin Neurophysiol 111:763–772CrossRefPubMedGoogle Scholar
  8. 8.
    Boon P, D’Havé M, Vanrumste B, Van Hoey G, Vonck K, Van Walleghem P (2002) Ictal source localization in presurgical patients with refractory epilepsy. J Clin Neurophysiol 19:461–468CrossRefPubMedGoogle Scholar
  9. 9.
    Brodbeck V, Spinelli L, Lascano AM, Wissmeier M, Vargas MI, Vulliemoz S, Pollo C, Schaller K, Michel CM, Seeck M (2011) Electroencephalographic source imaging: a prospective study of 152 operated epileptic patients. Brain 134:2887–2897CrossRefPubMedPubMedCentralGoogle Scholar
  10. 10.
    Ding L, Worrell GA, Lagerlunf TD, He B (2007) Ictal source analysis: localization and imaging of causal interactions in humans. Neuroimage 34:575–586CrossRefPubMedGoogle Scholar
  11. 11.
    Hirsch LJ, Spencer SS, Williamson PD, Spencer DD, Mattson RH (1991) Comparison of bitemporal and unitemporal epilepsy defined by depth electroencephalography. Ann Neurol 30:340–346CrossRefPubMedGoogle Scholar
  12. 12.
    Lantz G, Michel CM, Seeck M, Blanke O, Landis T, Rosen I (1999) Frequency domain EEG source localization of ictal epileptiform activity in patients with partial complex epilepsy of temporal lobe origin. Clin Neurophysiol 110:176–184CrossRefPubMedGoogle Scholar
  13. 13.
    Nemtsas P, Birot G, Pittau F, Michel CM, Schaller K, Vulliemoz S, Kimiskidis VK, Seeck M (2017) Source localization of ictal epileptic activity basedon high-density scalp EEG data. Epilepsia 58:1027–1036CrossRefPubMedGoogle Scholar
  14. 14.
    Rosenow F, Lüders H (2001) Presurgical evaluation of epilepsy. Brain 124:1683–1700CrossRefPubMedGoogle Scholar
  15. 15.
    Rosenzweig I, Fogarasi A, Johnsen B, Alving J, Fabricius ME, Scherg M, Neufeld MY, Pressler R, Kjaer TW, van Emde Boas W, Beniczky S (2014) Beyond the double banana: improved recognition of temporal lobe seizures in long-term EEG. J Clin Neurophysiol 31:1–9CrossRefPubMedGoogle Scholar
  16. 16.
    Scherg M (1994) From EEG source localisation to source imaging. Acta Neurol Scand, Suppl 152:29–30CrossRefPubMedGoogle Scholar
  17. 17.
    Scherg M (2011) Quick guide on 3D maps. http://www.besa.de/tutorials/quickguides/. Accessed 1 Feb 2018Google Scholar
  18. 18.
    Scherg M, Ebersole JS (1994) Brain source imaging of focal and multifocal epileptiform EEG activity. Neurophysiol Clin 24:51–60CrossRefPubMedGoogle Scholar
  19. 19.
    Scherg M, Ille N, Bornfleth H, Berg P (2002) Advanced tools for digital EEG review: virtual source montages, whole-head mapping, correlation, and phase analysis. J Clin Neurophysiol 19:91–112CrossRefPubMedGoogle Scholar
  20. 20.
    So N, Gloor P, Quesney LF, Jones-Gotman M, Olivier A, Andermann F (1989) Depth electrode investigations in patients with bitemporal epileptiform abnormalities. Ann Neurol 25:423–431CrossRefPubMedGoogle Scholar
  21. 21.
    Staljanssens W, Strobbe G, Holen RV, Birot G, Gachwind M, Seeck M, Vandenberghe S, Vulliemoz S, Van Mierlo P (2017) Seizure onset zone localization from Ictal high-density EEG in refractory focal epilepsy. Brain Topogr 30:257–271CrossRefPubMedGoogle Scholar
  22. 22.
    Yang L, Wilke C, Brinkmann B, Worrell GA, He B (2011) Dynamic imaging of ictal oscillations using non-invasive high-resolution EEG. Neuroimage 56:1908–1917CrossRefPubMedPubMedCentralGoogle Scholar

Copyright information

© Springer Medizin Verlag GmbH, ein Teil von Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Clinical NeurophysiologyDanish Epilepsy CentreDianalundDenmark
  2. 2.Department of Clinical NeurophysiologyAarhus University HospitalAarhusDenmark
  3. 3.Department of NeurologyKing George’s Medical UniversityLucknowIndia

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