Beyond the double banana: Improved recognition of temporal lobe seizures in long-term EEG

Ivana Rosenzweig, András Fogarasi, Birger Johnsen, Jørgen Alving, Martin Ejler Fabricius, Michael Scherg, Miri Y. Neufeld, Ronit Pressler, Troels W. Kjaer, Walter Van Emde Boas, Sándor Beniczky*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


PURPOSE: To investigate whether extending the 10-20 array with 6 electrodes in the inferior temporal chain and constructing computed montages increases the diagnostic value of ictal EEG activity originating in the temporal lobe. In addition, the accuracy of computer-assisted spectral source analysis was investigated. METHODS: Forty EEG samples were reviewed by 7 EEG experts in various montages (longitudinal and transversal bipolar, common average, source derivation, source montage, current source density, and reference-free montages) using 2 electrode arrays (10-20 and the extended one). Spectral source analysis used source montage to calculate density spectral array, defining the earliest oscillatory onset. From this, phase maps were calculated for localization. The reference standard was the decision of the multidisciplinary epilepsy surgery team on the seizure onset zone. Clinical performance was compared with the double banana (longitudinal bipolar montage, 10-20 array). RESULTS: Adding the inferior temporal electrode chain, computed montages (reference free, common average, and source derivation), and voltage maps significantly increased the sensitivity. Phase maps had the highest sensitivity and identified ictal activity at earlier time-point than visual inspection. There was no significant difference concerning specificity. CONCLUSIONS: The findings advocate for the use of these digital EEG technology-derived analysis methods in clinical practice.

Original languageEnglish
Pages (from-to)1-9
Number of pages9
JournalJournal of Clinical Neurophysiology
Issue number1
StatePublished - Feb 2014


  • Inferior temporal electrodes
  • Spectral source analysis
  • Virtual and source montages
  • Voltage and phase maps


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