4AT
The 4 'A's Test (4AT) is a bedside medical scale used to help determine if a person has positive signs for delirium.[1][2] The 4AT also includes cognitive test items, making it suitable also for use as a rapid test for cognitive impairment.[3]
The 4AT is designed to be used as a delirium detection tool in general
The 4AT has the most published
Some evidence shows that the 4AT can be implemented at scale in real-world clinical practice and that it shows positive score rates at comparable levels to the expected delirium prevalence rates.[24][25]
A 2022 two-center study in real-world clinical populations (total N=82,770) found that 4AT positive scores were aligned with expected delirium rates, and also were strongly linked with important outcomes including 30-day mortality, one-year mortality, hospital length of stay, and days at home in the year following hospital admission. Notably, the 4AT was completed as part of usual care by a large number of different staff (mostly doctors and nurses) who had not received special training in use of the 4AT. This study therefore showed that the 4AT is feasible in large-scale practice and that it provides real-time delirium ascertainment with positive scores being linked to important short and longer-term outcomes.[25]
Summary
| Full 4AT scale | ||
|---|---|---|
| Parameters and scoring | Points | |
| [1] Alertness
This includes patients who may be markedly and/or obviously sleepy during assessment) or agitated/hyperactive. Observe the patient. If asleep, attempt to wake with speech or a gentle touch on the shoulder. Ask the patient to state their name and address to assist rating. | ||
| Normal (fully alert, but not agitated, throughout assessment)
Mild sleepiness for <10 seconds after waking, then normal Clearly abnormal |
0
0 4 | |
| [2] AMT4
Age, date of birth, place (name of the hospital or building), current year. | ||
| No mistakes
1 mistake 2 or more mistakes/untestable |
0
1 2 | |
| [3] Attention
Ask the patient: "Please tell me the months of the year in backwards order, starting at December."To assist initial understanding one prompt of "what is the month before December?" is permitted. | ||
| Achieves 7 months or more correctly
Starts but scores <7 months / refuses to start Untestable (cannot start because unwell, drowsy, inattentive) |
0
1 2 | |
| [4] Acute change or fluctuating course
Evidence of significant change or fluctuation in alertness, cognition, other mental function (eg. paranoia, hallucinations) arising over the last 2 weeks and still evident in the last 24hrs | ||
| No
Yes |
0
4 | |
| 4AT TOTAL SCORE | ||
| SCORING KEY
4 or above: possible delirium +/- cognitive impairment 1-3: possible cognitive impairment 0: delirium or severe cognitive impairment unlikely (Delirium still possible if [4] information incomplete) | ||
The 4AT has 4 parameters:
- Alertness
- Abbreviated mental test-4 (AMT4)
- Attention (months backwards test)
- Acute change or fluctuating course
The score range is 0–12, with scores of 4 or more suggesting possible delirium. Scores of 1-3 suggest possible
There are several indications of a positive score of 4 or more. Parameters [1] and [4] can each individually trigger a positive score. The rationale is that both altered arousal and acute change in mental functioning are highly specific indicators of delirium.[26][27][28][29]
Parameters [2] and [3] provide embedded
Psychometric properties
A review of data to December 2019 involving 17 studies reported a pooled sensitivity of 88% and a pooled specificity of 88% for delirium diagnosis.[6] Since then, several additional validation studies have been published.[31][32][33][34][35][36]
A large, high quality (STARD-compliant) diagnostic randomized controlled trial comparing the 4AT and the Confusion Assessment Method (CAM) found that the 4AT had higher sensitivity and similar specificity to the CAM.[37]
Recommended use
The 4AT is intended to be used to assess for delirium on initial presentation with the patient, in transitions of care, in periods of high risk such as post-operatively and when delirium is suspected.[38] Using the 4AT multiple times per day for monitoring for new onset delirium for prolonged periods (weeks or more) is not recommended because of the burden of repeated cognitive testing on patients and staff.[39] However, it can be used 1-2 times per day for specified periods, e.g. peri-operatively. Additionally the 4AT is commonly used to monitor for recovery from active delirium. The 4AT is thus considered an episodic delirium test rather than a monitoring test. Use of the 4AT multiple times per day may be associated with lower compliance and overall performance because of the burden on staff and patients caused by performing several face to face interviews and cognitive testing per day.[33][40]
Shorter, largely observational tests such as the National Early Warning Score - 2 (NEWS2),[41] RADAR,[42] the Delirium Observation Scale (DOS),[43] the (Single Question in Delirium (SQiD)),[44] or the Nursing Delirium Screening Scale (Nu-DESC)[45] are more suitable for ongoing routine monitoring for new delirium after admission to hospital (or in long-term care settings).[46] A positive score in those tests generally then requires a more detailed assessment with a tool like the 4AT. This is an area of delirium practice which requires additional research.
The 4AT is one of several other delirium assessment tools in the literature.[47] Each varies in its intended use (research, severity grading, very brief screening, etc.), completion time, need for training, and psychometric characteristics.[48][49][50][51][2]
Languages
The 4AT has to date been translated into
References
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- ^ "National Audit of Dementia Reports and Resources". RC PSYCH ROYAL COLLEGE OF PSYCHIATRISTS. Retrieved 14 May 2020.
- ^ "National Hip Fracture Database: Annual Report 2019" (PDF). National Hip Fracture Database. Retrieved 14 May 2020.
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- ^ "SIGN 157 Delirium: Risk reduction and management of delirium". www.sign.ac.uk. Retrieved 14 May 2020.
- ^ "Delirium Clinical Care Standard" (PDF). Australian Commission on Safety and Quality in Health Care. Retrieved 14 May 2020.
- ^ "National Early Warning Score (NEWS) 2. Standardising the assessment of acute-illness severity in the NHS. Additional Implemenation Guidance March 2020". Retrieved 2 June 2020.
- ^ "Delirium Quality Standard: Tools for Implementation". Quorum. Retrieved 2021-05-13.
- ^ "Integrated Care Pathways and Delirium Algorithms". dementiapathways.ie. Retrieved 2021-05-13.
- ^ "4AT calculator". www.signdecisionsupport.uk. Retrieved 2021-05-13.
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- ^ a b "4AT – RAPID CLINICAL TEST FOR DELIRIUM". Retrieved 2020-05-14.
- ^ "Delirium detection in routine clinical care: two basic processes". DeliriumWords.com. 15 June 2020. Retrieved 2021-05-13.
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- ^ "NEWS2: Additional implementation guidance". RCP London. 2020-04-06. Retrieved 2020-06-18.
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- ^ "Delirium detection in routine clinical care: two basic processes". DeliriumWords.com. 15 June 2020. Retrieved 2021-01-12.
- ^ "A classification of delirium assessment tools". DeliriumWords.com. 13 July 2020. Retrieved 2020-11-28.
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- ^ "Adult Delirium Measurement Info Cards – NIDUS". Retrieved 14 May 2020.