Detecting Delirium

A study trialling a delirium detection assessment method, for use in hospitals, has been funded by the NIHR Health Technology Assessment (HTA) Programme.

Delirium is a change in mental function mainly affecting concentration, but symptoms can also include agitation, drowsiness, hallucinations and paranoia. Typically brought on by other illness, or as a side effect of drugs, it is extremely common in older people. Over a quarter of elderly patients in hospital have the condition.

"Delirium is a serious condition and can be highly distressing for both the patient and their carers," says Professor Alasdair MacLullich, the study's lead researcher based at the University of Edinburgh. "Delirium can extend the length of stay in hospital, and people with delirium more likely to be admitted to a nursing home straight after their hospital stay. Unfortunately delirium is also associated with a higher risk of medical complications."

Although the condition can carry severe risks, the formal diagnosis rates of delirium are very low. With over two thirds of cases currently going undetected, improving the methods of identifying the disorder is a major priority for the NHS. While there are many detection methods available, none seem suitable for routine use in hospitals due to the specialist training needed or length of time required to carry out the procedures.

The study will therefore trial a new method called the 4 "A"s Test, or 4AT (, which is a very simple and quick observation and questioning tool. Taking on average just two minutes to complete, patients will be assessed against four fixed points:

  1. Alertness – is the patient drowsy?
  2. AMT4 – Can the patient confirm details such as their age, date of birth and current year?
  3. Attention – Can the patient recite the months of the year backwards?
  4. Acute changes – Has the patient experienced significant deterioration in their mental functioning in the last two weeks? in mental functions such as paranoia and hallucinations?

Although 4AT is already used in a small number of hospitals, it requires further research to see if it is suitable for wider implementation. The study, formed in two parts, aims to confirm if the test can be used on large numbers of people. The first part will involve consultations with health professionals, patients and carers to refine the tool and explore general barriers to delirium detection. Secondly, the revised 4AT will be tested against existing detection methods on 900 hospitalised patients.

"If the project is successful there's real potential to have an important impact on the NHS," says Professor MacLullich. "The tool could greatly increase delirium detection rates and really improve the wellbeing of people with this very common but neglected condition."

For further information of the trial, please visit the project page.