The human brain has the capacity to rapidly change state, and in epilepsy these state changes can be catastrophic, resulting in loss of consciousness, injury and even death. Theoretical interpretations considering the brain as a dynamical system suggest that prior to a seizure, recorded brain signals may exhibit critical slowing down, a warning signal preceding many critical transitions in dynamical systems. Using long-term intracranial electroencephalography (iEEG) recordings from fourteen patients with focal epilepsy, we monitored key signatures of critical slowing down prior to seizures. The metrics used to detect critical slowing down fluctuated over temporally long scales (hours to days), longer than would be detectable in standard clinical evaluation settings. Seizure risk was associated with a combination of these signals together with epileptiform discharges. These results provide strong validation of theoretical models and demonstrate that critical slowing down is a reliable indicator that could be used in seizure forecasting algorithms.

Boston Children's Hospital Boston MA USA

Centre for Human Psychopharmacology Swinburne University of Technology Hawthorn Victoria Australia

Department of Biomedical Engineering The University of Melbourne Melbourne Australia

Department of Circuit Theory Faculty of Electrical Engineering Czech Technical University Prague Prague Czech Republic

Department of Developmental Epileptology Institute of Physiology Czech Academy of Sciences Prague Czech Republic

Department of Medicine St Vincent's Hospital The University of Melbourne Melbourne Australia

Department of Neurology University Clinic Carl Gustav Carus Dresden Germany

Department of Physiology 2nd Faculty of Medicine Charles University Prague Czech Republic

Faculty of Information Technology Monash University Clayton Victoria Australia

Graeme Clark Institute The University of Melbourne Melbourne Australia

Institute of Computer Science of the Czech Academy of Sciences Prague Czech Republic

National Institute of Mental Health Klecany Czech Republic

Seer Medical Melbourne Australia

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