The correlation of EEG compressed spectral array to Glasgow coma scale in traumatic coma patients

Abstract

We have studied 20 comatose intensive care patients with head injuries and/or intracranial, haemorrhage in order to compare two different monitoring methods of the central nervous system. The level of unconsciousness was followed on the Glasgow Coma Scale (GCS). EEG was monitored continuously with the compressed spectral array (CSA)-method. CSA findings were classified into six categories according to the frequency content, reactivity and the amount of isoelectricity. The patients were divided into four groups according to the outcome: well-recovered, moderately recovered, poorly recovered and dead. The prognostic value of the data obtained with the GCS method was compared with that obtained by CSA.

The CSA and GCS methods give information based on different neurophysiological backgrounds. This explains why the correlation of these methods was only moderate. When combining the information received from these two methods the predictability improved. In many acute situations CSA gave information about changes in the brain function, which could not be seen in GCS. The results suggest that CSA is not only a supplementary method to GCS but also a different approach to the monitoring of an unconscious patient.