[Is it possible to extract intracranial pressure information based on the EEG activity?]

The capability of the electroencephalography (EEG) of recording the bioelectrical activity of the brain has made of it a fundamental tool for the evaluation of the patient's neurological condition. In recent years, moreover, it has also begun to be used in obtaining information for other kind of variables, as the ones related with the cerebral hemodynamics.

To study the potential relationship between the EEG activity and the intracranial pressure (ICP) in patients suffering from traumatic brain injury and subarachnoid hemorrhage, during their stay at the intensive care unit.

Twenty-one adult patients (10 women) were included in the present observational prospective cohort study. They suffered from either traumatic brain injury or subarachnoid hemorrhage, requiring continuous EEG and ICP monitoring. In every patient, Granger causality between spectral functions of the EEG and the ICP was evaluated. Temporal windows of 10 minute were used to evaluate whether a causal relationship between those variables exist or not. In all of the cases, several days of continuous recording and assessment were performed.

In most patients and during most of the time, Granger causality turns out to be significant in the direction from the EEG to the ICP, meaning that the EEG dynamics actually leads the ICP dynamics.

The present work provides useful information and shed light in discovering a hidden relationship between the ICP and EEG dynamics. The potential use of this relationship could lead to develop a medical device to measure ICP in a non-invasive fashion.