Resection of high frequency oscillations predicts seizure outcome in the individual patient

• Published in: Scientific reports 2017-10, Vol.7 (1), p.13836-10, Article 13836
• Main Authors: Fedele, Tommaso, Burnos, Sergey, Boran, Ece, Krayenbühl, Niklaus, Hilfiker, Peter, Grunwald, Thomas, Sarnthein, Johannes
• Format: Article
• Language: English
• Subjects: 692/308/53/2421; 692/617/375/178; Adult; Algorithms; Automation; Brain - physiopathology; Brain Mapping - methods; Drug Resistant Epilepsy - diagnosis; Drug Resistant Epilepsy - surgery; Electroencephalography - methods; Epilepsy; Female; Humanities and Social Sciences; Humans; Male; Middle Aged; multidisciplinary; Neurosurgery; Oscillations; Patients; Prospective Studies; Science; Science (multidisciplinary); Seizures; Seizures - diagnosis; Seizures - surgery; Surgery; Treatment Outcome; Young Adult
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-13064-1

High frequency oscillations (HFOs) are recognized as biomarkers for epileptogenic brain tissue. A remaining challenge for epilepsy surgery is the prospective classification of tissue sampled by individual electrode contacts. We analysed long-term invasive recordings of 20 consecutive patients who subsequently underwent epilepsy surgery. HFOs were defined prospectively by a previously validated, automated algorithm in the ripple (80–250 Hz) and the fast ripple (FR, 250–500 Hz) frequency band. Contacts with the highest rate of ripples co-occurring with FR over several five-minute time intervals designated the HFO area. The HFO area was fully included in the resected area in all 13 patients who achieved seizure freedom (specificity 100%) and in 3 patients where seizures reoccurred (negative predictive value 81%). The HFO area was only partially resected in 4 patients suffering from recurrent seizures (positive predictive value 100%, sensitivity 57%). Thus, the resection of the prospectively defined HFO area proved to be highly specific and reproducible in 13/13 patients with seizure freedom, while it may have improved the outcome in 4/7 patients with recurrent seizures. We thus validated the clinical relevance of the HFO area in the individual patient with an automated procedure. This is a prerequisite before HFOs can guide surgical treatment in multicentre studies.