Delirium scales: A review of current evidence

Objectives: Delirium is a common neuropsychiatric condition with many adverse outcomes in elderly populations including death. Despite this, it is often misdiagnosed and mistreated. A number of scales can be used to detect delirium. We review scales that have been used in delirium studies and report their psychometric properties. Method: An extensive MEDLINE database search and subsequent examination of reference lists was conducted to identify the various delirium scales that have been designed, primarily for use in the elderly. Results: Twenty-four scales were identified. Delirium instruments differed according to the classification system they were based on, length of time to administer, the rater and whether they were screening scales or measured symptom severity. The psychometric properties of each scale is reported. Conclusion: A large number of scales exist, but not all are properly evaluated in terms of psychometric properties, and there is not unanimity about which scale is the best. However, a small number of scales may be considered already to be robust and useable: the CAM, the DRS, the MDAS and the NEECHAM.