Introduction: 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.
Aim: 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.
Patients and methods: 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.
Results: 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.
Conclusions: 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.
Title: Es posible obtener informacion de la presion intracraneal a partir de la actividad electroencefalografica?
Introduccion. El electroencefalograma (EEG) permite obtener informacion directa de la actividad bioelectrica del cerebro y es una herramienta fundamental para la evaluacion de la condicion neurologica del paciente. En los ultimos años ha comenzado a emplearse tambien para obtener indirectamente informacion sobre la hemodinamica cerebral y las variables que intervienen en la autorregulacion del flujo sanguineo cerebral. Objetivo. Estudiar la posible relacion entre la actividad electroencefalografica y la presion intracraneal (PIC) en pacientes con traumatismo craneoencefalico y hemorragia subaracnoidea ingresados en cuidados intensivos. Pacientes y metodos. Se incluyo a 21 pacientes (10 mujeres) mayores de 18 años con traumatismo craneoencefalico o hemorragia subaracnoidea que requerian monitorizacion de la PIC y a los que se les registro el EEG de forma continua. Se determino la causalidad de Granger entre la PIC con respecto a las variables espectrales del EEG para ventanas temporales de 10 minutos durante la estancia en cuidados intensivos. Resultados. La causalidad de Granger mostro una alta correlacion entre la PIC con las bandas del EEG. En la mayoria de los pacientes existe una causalidad de Granger significativa en la direccion del EEG hacia la PIC en gran parte del tiempo de monitorizacion, de forma que las variables del EEG precedian a la PIC. Conclusiones. El presente trabajo expone la relacion temporal subyacente entre la dinamica de la PIC y la actividad bioelectrica cerebral registrada mediante EEG en pacientes con traumatismo craneoencefalico y hemorragia subaracnoidea. El potencial uso de esta relacion podria permitir estimar la PIC de manera no invasiva.