Recently, brain imaging has provided controversial evidence of persisting awareness in some people whose brains are so severely injured that consciousness is minimal or absent, but in whom prolongation of life depends on the provision of continuing medical care. The clinicians understanding of the persistent vegetative state is briefly outlined and the evidence provided by brain imaging of awareness in this condition is reviewed. Information regarding consciousness in progressive acquired dementias are considered in the context of management of these conditions. This leads to the conclusion that quality of consciousness was more important than its presence or absence in managing people with impaired consciousness.