Many of cardiac arrest patients treated at an intensive care unit will die, mostly after a decision of withdrawal of care due to a prognostication of severe hypoxic brain damage. The decision is based on clinical examination in combination with other prognostic methods, where EEG is the most widely used. EEG can show the recovery of normal brain activity or appearance of different pathological patterns. However, international consensus is still lacking on how EEG interpretation should be done to become a reliable prognostic tool. The aim of this thesis is to evaluate and identify standardized EEG methods for reliable prognostication of post arrest brain damage.