Delirium is a severe psychiatric syndrome that is highly prevalent in elderly 
general hospital patients. However, the diagnosis of delirium is often missed. 
The use of rating scales can be helpful in detecting and measuring delirium 
symptom severity. This article reviews recent developments with regard to 
psychometric qualities, measurement goal, content and rating procedures of some 
of the available rating scales in clinical practise. Studies that used delirium 
rating scales were searched for using the MEDLINE and subsequent examination of 
reference lists. Ten rating scales were selected for further evaluation. The 
Confusional Assessment Method (CAM), NEECHAM Confusion Scale (NEECHAM) and 
Delirium Observation Scale (DOS) appear to be most suitable as a screening 
instrument, depending on the type of rater (physician or nurse). The (revised) 
Delirium Rating Scale (DRS(-R-98)) seems to be particularly useful for measuring 
delirium severity or monitoring change.