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Ictal EEG source imaging

Quellenanalyse iktaler EEG-Daten

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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.

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..

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Acknowledgements

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

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Authors and Affiliations

  1. Department of Clinical Neurophysiology, Danish Epilepsy Centre, Visby Allé 5, 4293, Dianalund, Denmark

    Sándor Beniczky MD, PhD & Praveen Sharma MD

  2. Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark

    Sándor Beniczky MD, PhD

  3. Department of Neurology, King George’s Medical University, Lucknow, India

    Praveen Sharma MD

Authors
  1. Sándor Beniczky MD, PhD
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  2. Praveen Sharma MD
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Corresponding author

Correspondence to Sándor Beniczky MD, PhD.

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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.

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Beniczky, S., Sharma, P. Ictal EEG source imaging. Z. Epileptol. 31, 197–202 (2018). https://doi.org/10.1007/s10309-018-0184-z

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  • DOI: https://doi.org/10.1007/s10309-018-0184-z

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