This calculator is for general information and education. It is not medical advice and does not replace the judgment of a doctor, nurse or pharmacist who knows the full clinical picture.
Spotting delirium quickly
Delirium is an acute confusional state that develops over hours or days, with fluctuating attention and awareness. It affects up to one in four older adults admitted to hospital, is often missed, and is linked to falls, longer stays, dementia and death. The 4AT is a rapid screening test designed so that any doctor or nurse can check for it in under two minutes, without special training.
The four items
- Alertness: is the patient normal, or clearly drowsy or agitated? Mild sleepiness for under ten seconds after waking counts as normal. Clearly abnormal alertness scores 4.
- AMT4: age, date of birth, place and current year. No mistakes scores 0, one mistake scores 1, two or more mistakes or an untestable patient scores 2.
- Attention: ask the patient to name the months of the year backwards, starting from December. Seven months or more correct scores 0, starting but scoring fewer than seven or refusing scores 1, and being untestable because unwell, drowsy or inattentive scores 2.
- Acute change or fluctuating course: evidence of a significant change or fluctuation in alertness, cognition or other mental function in the last two weeks and still present in the last 24 hours scores 4.
Interpreting the total
| Score | Meaning |
|---|---|
| 0 | Delirium or severe cognitive impairment unlikely |
| 1 – 3 | Possible cognitive impairment |
| ≥ 4 | Possible delirium, with or without cognitive impairment |
Example
An alert patient who gets the year wrong but answers the other AMT4 questions correctly, names the months backwards without trouble and has no reported change in mental state scores 1. This suggests possible cognitive impairment rather than delirium, and more detailed testing is worthwhile.
After a positive screen
A score of 4 or more is not a diagnosis. It calls for a clinical assessment and a search for the common triggers: infection, new medicines, dehydration, pain, constipation, urinary retention, low oxygen or alcohol withdrawal. Delirium is often reversible when its cause is treated, and simple measures, such as glasses, hearing aids, orientation, sleep and early mobility, help prevent it.