Delirium has conventionally been considered a disorder of consciousness, but this remains a relatively unexamined precept. First, a review of the role of consciousness disruption in delirium is revised from an historical and diagnostic perspective. Second, consciousness measurement in routine assessment of delirium is considered. Conscious levels, comprising alertness and arousal, are most commonly used but are not representative of the multidimensionality of consciousness. Third, a justification for the exploration of phenomenal consciousness is presented. Three candidate dimensions of phenomenal consciousness (...) are identified as the pre-reflective state, phenomenal experience, and reflective thought. Finally, the clinical implications of a deeper understanding of delirium through measurement of phenomenal consciousness is considered. (shrink)