AI-based Algorithm Development for Improved Diagnostics in the Intensive Care and Acute Stroke Setting Using Electroencephalography

Inclusion Criteria: All participants: \- Age 18 years or older Postanoxic coma (ICU): * Postanoxic coma after cardiac arrest, admitted to the intensive care unit * No objection to participation within 4 weeks of receiving an opt-out information letter Suspected stroke (emergency department): * Suspected stroke as assessed by the ambulance personnel presenting the patient to the emergency department, or confirmed stroke. * Symptom onset, or last seen well if onset was not witnessed, less than 24 hours ago. * Written (deferred) informed consent by the patient or legal representative Suspected subarachnoid hemorrhage (emergency department): * Suspected subarachnoid hemorrhage as judged by the attending ambulance paramedic, or confirmed subarachnoid hemorrhage. * Symptom onset, or last seen well if onset was not witnessed, less than 48 hours ago. * Written (deferred) informed consent by the patient or legal representative. Exclusion Criteria: All participants: \- (Suspected) skin damage or infection at the placement area of the subhairline EEG patch Postanoxic coma (ICU): \- Other types of severe brain injury, either pre-existing or coinciding with cardiac arrest. These include stroke, traumatic brain injury and progressive neurodegenerative disease.