The value of electroencephalography in prolonged coma: a comparative EEG-computed axial tomography study of two...

Interest was aroused in two patients of 16 and 17 years of age and similar craniocerebral trauma, but who had differing EEG's 1 year after injury while their later situation was the reverse of what the EEG would have led one to expect. The patient with an iso-electric EEG showed clinical improvement during the course of the second year, as indicated by a rise in his Glasgow coma rating from 8 to 11. This patient had marked cortical atrophy with discrete central atrophy, shown by computed axial tomography (CT); the isotope cisternogram showed good peripheral absorption of the isotope and no penetration into the ventricles. The other patient showed diffuse slow-wave activity in his EEG but failed to improve clinically or electroencephalographically. His CT-scan showed marked central and discrete cortical atrophy; his isotopic cisternogram showed penetration of isotope into the ventricles with poor peripheral absorption. These two cases illustrate the hazard of relying on an iso-electric EEG after 1 year of coma as an indicator of brain death, and the value of the CT-scan in the initial assessment of such cases.