A prospective, multicenter study of cardiac-based seizure detection to activate vagus nerve stimulation

Paul Boon*, Kristl Vonck, Kenou van Rijckevorsel, Riem El Tahry, Christian E. Elger, Nandini Mullatti, Andreas Schulze-Bonhage, Louis Wagner, Beate Diehl, Hajo Hamer, Markus Reuber, Hrisimir Kostov, Benjamin Legros, Soheyl Noachtar, Yvonne G. Weber, Volker A. Coenen, Herbert Rooijakkers, Olaf E. M. G. Schijns, Richard Selway, Dirk Van RoostKatherine S. Eggleston, Wim Van Grunderbeek, Amara K. Jayewardene, Ryan M. McGuire

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Purpose: This study investigates the performance of a cardiac-based seizure detection algorithm (CBSDA) that automatically triggers VNS (NCT01325623). Methods: Thirty-one patients with drug resistant epilepsy were evaluated in an epilepsy monitoring unit (EMU) to assess algorithm performance and near-term clinical benefit. Long-term efficacy and safety were evaluated with combined open and closed-loop VNS. Results: Sixty-six seizures (n = 16 patients) were available from the EMU for analysis. In 37 seizures (n = 14 patients) a >= 20% heart rate increase was found and 11 (n = 5 patients) were associated with ictal tachycardia (iTC, 55% or 35 bpm heart rate increase, minimum of 100 bpm). Multiple CBSDA settings achieved a sensitivity of >= 80%. False positives ranged from 0.5 to 7.2/h. 27/66 seizures were stimulated within +/- 2 min of seizure onset. In 10/17 of these seizures, where triggered VNS overlapped with ongoing seizure activity, seizure activity stopped during stimulation. Physician-scored seizure severity (NHS3-scale) showed significant improvement for complex partial seizures (CPS) at EMU discharge and through 12 months (p <0.05). Patient-scored seizure severity (total SSQ score) showed significant improvement at 3 and 6 months. Quality of life (total QOLIE-31-P score) showed significant improvement at 12 months. The responder rate (>= 50% reduction in seizure frequency) at 12 months was 29.6% (n = 8/27). Safety profiles were comparable to prior VNS trials. Conclusions: The investigated CBSDA has a high sensitivity and an acceptable specificity for triggering VNS. Despite the moderate effects on seizure frequency, combined open- and closed-loop VNS may provide valuable improvements in seizure severity and QOL in refractory epilepsy patients.
Original languageEnglish
Pages (from-to)52-61
Publication statusPublished - Nov 2015


  • Vagus nerve stimulation
  • Ictal tachycardia
  • Cardiac based seizure detection
  • Refractory epilepsy
  • Quality of life

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