EEG lateralization and seizure outcome following peri-insular hemispherotomy for pediatric hemispheric epilepsy

  • Ananth P. Abraham
  • Maya Mary ThomasEmail author
  • Vivek Mathew
  • Karthik Muthusamy
  • Sangeetha Yoganathan
  • G. Edmond Jonathan
  • Krishna Prabhu
  • Roy Thomas Daniel
  • Ari G. Chacko
Original Article



To determine whether preoperative non-lateralizing scalp electroencephalography (EEG) influences seizure outcome following peri-insular hemispherotomy (PIH) in pediatric hemispheric epilepsy.


Retrospective data was collected on all 45 pediatric patients who underwent PIH between 2005 and 2016. All underwent a basic pre-surgical evaluation consisting of detailed history and examination, neuropsychological assessment, MRI, and EEG. SPECT/PET, fRMI, or Wada testing were done in only eight patients. Seizure outcome was assessed using the Engel classification.


Among those who underwent hemispherotomy, 20 (44%) were females. Mean age at surgery was 8 ± 4.3 years and mean duration of symptoms was 5.2 ± 3.7 years. The most common etiologies of hemispheric epilepsy were hemiconvulsion-hemiplegia epilepsy syndrome, Rasmussen encephalitis, and post-encephalitic sequelae, together comprising 27 (60%) patients. Among the 44 patients with follow-up data (mean duration 48 ± 33 months), seizure freedom (Engel class I) was attained by 41 (93.2%). Anti-epileptic medications were stopped or decreased in 36 (82%). Seventeen (38.6%) patients had non-lateralizing EEG. Seizure outcome was not related to lateralization of EEG activity.


PIH provides excellent long-term seizure control in patients despite the presence of non-lateralizing epileptiform activity, although occurrence of acute postoperative seizures may be higher. Routine SPECT/PET may not be required in patients with a non-lateralizing EEG if there is good clinico-radiological concordance.


Epilepsy surgery Hemispherotomy Peri-insular EEG Seizure outcome 


Compliance with ethical standards

The authors report no conflict of interest. The datasets generated for the study are available from the corresponding author on reasonable request.


A portion of this study was presented as a podium presentation at the 66th Annual Conference of the Neurological Society of India in December, 2017.

Conflict of interest



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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Ananth P. Abraham
    • 1
  • Maya Mary Thomas
    • 1
    Email author
  • Vivek Mathew
    • 1
  • Karthik Muthusamy
    • 1
  • Sangeetha Yoganathan
    • 1
  • G. Edmond Jonathan
    • 1
  • Krishna Prabhu
    • 1
  • Roy Thomas Daniel
    • 2
  • Ari G. Chacko
    • 1
  1. 1.Department of Neurological SciencesChristian Medical CollegeVelloreIndia
  2. 2.Department of NeurosurgeryUniversity Hospital of LausanneLausanneSwitzerland

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