Hence, in the third generation of brain death criteria, the disappearance of evoked potentials is, in our opinion, the best of the new tests. There are, therefore, three tests alternatively available: ECS, EP-abolition and CCA, which permit a shortening of the observation time, before the determination of brain death. This is not valid for newborns. In these tests the difference between supratentorial and infratentorial primary brain lesions has to be considered carefully. In infratentorial lesions the apnea can precede the ECS by several hours.