Diagnosing consciousness: neuroimaging, law, and the vegetative state.

In this paper, we review recent neuroimaging investigations of disorders of consciousness and different disciplines' understanding of consciousness itself. We consider potential tests of consciousness, their legal significance, and how they map onto broader themes in U.S. statutory law pertaining to advance directives and surrogate decision-making. In the process, we outline a taxonomy of themes to illustrate and clarify the variance in state-law definitions of consciousness. Finally, we discuss broader scientific, ethical, and legal issues associated with the advent of neuroimaging for disorders of consciousness and conclude with policy recommendations that could help to mitigate confusion in this realm.