There is no agreement as to where the limits of consciousness lie, or even if these putative borders exist. Problems inherent in the study of consciousness continue to confound efforts to establish a universally-accepted theory of consciousness. Consequently, clinical definitions of consciousness and unconsciousness are unavoidably arbitrary. Recently, a condition of severely altered consciousness has been described that characterizes the borderzone between the vegetative state and so-called "normal" consciousness. This condition, referred to as the minimally conscious state (MCS), is distinguished from the vegetative state by the presence of minimal but clearly discernible behavioral evidence of self or environmental awareness. This presentation will review the diagnostic criteria, neuroanatomic/neurophysiologic profile, prognostic relevance and treatment implications associated with MCS.

Selected references:
Giacino JT, Ashwal S, Childs N, Cranford R, Jennett B, Katz DI, Kelly JP,Rosenberg JH, Whyte J, Zafonte RD, Zasler ND. The minimally conscious state: definition and diagnostic criteria. Neurology. 2002;58:349-53
Giacino JT. Disorders of consciousness: differential diagnosis and neuropathologic
features. Semin Neurol. 1997 ; 17:105-11.