A critical analysis of conceptual domains of the vegetative state: sorting fact from fancy.

Neurophysiological research on the vegetative state (VS) presupposes a clearly defined patient population. VS has been variously defined in three domains: anatomy, behavior, and consciousness. Research on each conceptual type of "VS" is reviewed. Certain key elements of official VS dogma are cast into doubt or flatly contradicted by recent noninvasive neurophysiological studies. "Behavioral VS" is often the manifestation of a multi-modular disconnection syndrome rather than the complete absence of cortical functioning. Some "behavioral VS" may represent a "super locked-in state," with some primitive awareness of self and environment, including the capacity to experience pain. The term VS should be dropped and replaced with one that reflects what is truly known and verifiable about the condition and the individual patient.