Minimally conscious state: Evolution of concept, diagnosis and treatment

Abstract

The study of consciousness disorders is a scientific challenge, and clinical differentiation among the various sorts of alterations in consciousness is difficult. Persistent vegetative state was defined in 1972, but years later cases appeared in which diagnosed patients showed signs of cognitive activity, and therefore could not be considered vegetative. Minimally conscious state was defined in 2002. This article discusses minimally conscious state based on a literature review and the author's clinical experience. A brief historical outline is given, starting from 1886 when Horsley analyzed level of consciousness. The article reviews criteria for defining minimally conscious state, as well as the differential diagnosis from persistent vegetative state, brain death, coma, locked-in syndrome and akinetic mutism. Modern discoveries of residual cognitive functioning and new neural correlates have contributed to increased knowledge of this condition. Regardless, minimally conscious state continues to be a challenge for neuroscientists around the world, with issues still to be resolved.