Chronic subthreshold cortical stimulation and stimulation-related EEG biomarkers for focal epilepsy

Brian Nils Lundstrom, Jamie Van Gompel, Fatemeh Khadjevand, Greg Worrell, Matt Stead

Research output: Contribution to journalArticlepeer-review


Brain stimulation offers an alternative to focal resection for the treatment of focal drug-resistant epilepsy. Chronic subthreshold cortical stimulation is an individualized biomarker-informed open-loop continuous electrical stimulation approach targeting the seizure onset zone and surrounding areas. Before permanent implantation, trial stimulation is performed during invasive monitoring to assess stimulation efficacy as well as to optimize stimulation location and parameters by modifying interictal EEG biomarkers. We present clinical and neurophysiological results from a retrospective analysis of 21 patients, showing a median percent reduction in seizure frequency of 100% and responder rate of 89% with a median follow-up of 27 months. About 40% of patients were free of disabling seizures for a 12-month period or longer. We find that stimulation-induced decreases in delta (1-4 Hz) power and increases in alpha and beta (8-20 Hz) power during trial stimulation correlate with improved long-term clinical outcomes. These results suggest chronic subthreshold cortical stimulation may be an effective alternative approach to treating focal drug-resistant epilepsy and that short-term stimulation-related changes in spectral power may be a useful interictal biomarker and relate to long-term clinical outcome.

Original languageEnglish (US)
Article numberfcz010
JournalBrain Communications
Issue number1
StatePublished - 2019


  • EEG biomarkers
  • brain stimulation
  • chronic subthreshold cortical stimulation
  • focal epilepsy
  • trial stimulation

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Biological Psychiatry
  • Cellular and Molecular Neuroscience
  • Neurology


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