During recent years more and more newly scientific technologies are applied to the study of consciousness. A lot of advancement have been made in the area of disorders of consciousness (DOC). Due to the complexity of brain function and different etiology and complications of DOC, the application of those newly methods for diagnosis of DOC become very difficult. Clincal guidelines were published by American and European academies successively. The guideline of European Academy of Neurology gave a series of clinical questions and answers including bedside examination, functional neuroimaging and electroencephalography based on evidence. Here we interpret it briefly in order to better guide our practice.