Delirium screening has not been introduced systematically in N-ICUs in Denmark or internationally, and validated instruments are lacking in this population. The Confusion Assessment Method for ICU (CAM-ICU) and the Intensive Care Delirium Screening Checklist (ICDSC) are internationally most recommended and best validated delirium screening tools for non-psychiatric health care staff. Neither of the two instruments, however, has been fully validated in patients with acquired brain injury.