Abstract
Disturbances of consciousness reflect failing vital functions and signalize an urgent medical condition. The possibility to communicate with the patient and the quality of contact are the first information the physician obtains.
Reduced vigilance and associated quantitative disturbances of consciousness are the subject of interest and training in disciplines like urgent medicine, neurology and neurosurgery. The phenomenology and the differential diagnosis of the disturbances of awareness and associated qualitative disturbance of consciousness remain the focus if interest in psychiatry.
Understanding of the disturbances of consciousness mirror different approaches based partly on German phenomenology, and in part on contemporary evidence based approaches. The advance of neuroscience led to a greater interest in chronic disorders of consciousness and the disconnection of communication and conscious experience among patients in the vegetative state.