[Evolution of the conditions for EEG recording in the diagnosis of brain death]

The authors trace the evolution of conditions of EEG recording parallel to the clinical criteria of certainty of the diagnosis of brain death, since the first definition of irreversible coma given by M. Goulon and P. Mollaret in 1959. They notice that over the past 30 years, the duration of the EEG has been reduced, their frequency decreased, and the delay between the clinical diagnosis of brain death with flat EEG and the switching off of the cardio-respiratory ventilation have been reduced from 48 to 6 h, thus enabling extremely early removal of organs; the slow progress of this evolution is explained by the difficulty over the years in distinguishing between brain death and certain reversible pathological conditions which resemble it, and by the fact that some EEGs may take some time to become flat. Actually, once these special cases have been eliminated, after the clinical diagnosis of brain death has been ascertained, we observe that two flat EEGs at an interval of 6 h are never subsequently modified. Finally, the EEG, a non-invasive method, seems always to be the quickest and the easiest method to carry out and especially to repeat, without any particular problem of staff or of place and is, thus, a reliable testimony in the event of medico-legal controversy.