After any acute brain injury, a primary pathophysiological response arises, enabling the brain to develop seizures and/or a status epilepticus (SE). These are frequently reported in patients admitted to the intensive care unit (ICU) with traumatic brain injury and brain injury caused by subarachnoid or intracerebral hemorrhage. Seizures can be presented without any clinical motor signs, which are then termed as nonconvulsive, and therefore remain frequently clinically unrecognized. As such, it is of great importance that these patients are diagnosed as early as possible since the increased metabolic demand and blood flow associated with an epileptic insult may further compromise the brain at risk. Thus far, continuous EEG (cEEG) is the only clinical instrument that is able to detect the development of early epileptic activity. Unfortunately, cEEG is not available in most ICUs and is labor-intensive, expensive and difficult to interpret for non-trained physicians. Therefore, a more simple and prognostic accurate EEG device is highly warranted to detect seizures in an early stage so that patients might benefit from a specific and early treatment. A validation study in comatose patients with an acute neurological insult will be conducted to provide evidence that simplified Bispectral Index EEG monitoring has the potential to detect epileptic activity as reliable as its gold standard, full EEG monitoring. Thereby, BIS EEG monitoring could possibly be used to facilitate the prognostication and management of epileptic seizures in this patient cohort which could eventually improve the clinical outcome.

Inclusion Criteria:

• Patients (age ≥ 18 years) admitted to the ICU with an acute neurological insult which will be sedated/ventilated (Glasgow Coma Scale (GCS) ≤ 8).
• Ability to place BIS sensors on the forehead
• Written informed consent form has to be obtained from the patient's next of kin and has to be reconfirmed if the patient regains consciousness

Exclusion Criteria:

• Age < 18 years
• Inability to place BIS sensors on the forehead (e.g. due to frontal decompression)