Disorders of Consciousness.

The brain generates the mind and the healthy, wakeful mind formulates consciousness. The American psychologist William James in 1890 stated, 'Consciousness is the [indispensable] fundmental awareness of the self's internal ego.' He then expanded that self-centered focus to identify the self's greater qualities of memory, attention, intention, chronological time, emotion, learned behavior and several other less general psychological qualities. At that early time, only philosophical thinking interpreted gross anatomic knowledge in understanding how the awake brain might lose conscious functions. Modern neurological medicine has defined several distinct behavioral pathological states that arise from inherited and acquired brain injuries and lead to disorders of consciousness. Brain injuries that reflect global disorders of consciousness include stupor and coma, the vegetative state, akinetic mutism, absence and partial complex seizures, delirium, and severe dementia. These global disorders, described below, totally disable the capacity of the individual for intentional behaviors. Though different in pattern, 'focal' disorders of consciousness can exist in several serious illnesses. A patient suffering a focal disorder of consciousness can be awake and interact with the environment, and yet exhibit severe alterations in awareness. These disorders uniquely illustrate the constructed nature of conscious experience.