How to Perform the 4 A’s Test of Delirium: Simple, Quick and Reliable.
Introduction
Delirium is a severe change in mental abilities, causing confusion and reduced awareness, and is a common and serious complication within the elderly population. It is often misdiagnosed, missed or diagnosed late. Delirium may start rapidly, fluctuate and may persist for hours to days. Thus, it is crucial in the emergency department or patients on a ward or at a patient's house to quickly and efficiently identify patients presenting with delirium. There are many reasons for delirium to occur. The mnemonic PINCHES ME or I WATCH DEATH can be used to find the cause and treat adequately as delirium is usually transient, reversible and preventable.
The 4 A's test help practitioners to quickly identify and detect delirium in a patient. It is simple, quick, has adequate sensitivity/specificity and has been well validated and accepted in medicine to screen for delirium. Using the 4 A's test, anybody can quickly identify when a patient has a delirium episode as it does not require special training. This test can also be helpful when other tests have not been successful.
There are some pitfalls. It is noteworthy that differentiating delirium and dementia is a must. The 4 A's test cannot be done if there is a background of dementia, as the results could be misleading. It does not help that delirium often occurs with people who suffer from dementia but having delirium does not mean a person has dementia.
The 4 A’s test creators are Dr Giuseppe Bellelli and Dr Alasdair MacLullich. Giuseppe Bellelli, MD, is a geriatric physician at the Azienda Ospedaliera San Gerardo in Monza, Italy. He is also an associate professor in the department of medicine and surgery at the Università degli Studi di Milano-Bicocca. Dr Bellelli's research interests include ageing, delirium, and behavioural and psychotic symptoms of dementia (BPSD). Alasdair MacLullich, BSc, MB ChB, MRCP(UK), PhD, FRCPE, is a professor of geriatric medicine at the University of Edinburgh in Scotland. He also leads the Edinburgh Delirium Research Group to improve the understanding, detection and treatment of delirium. Dr MacLullich's primary research is focused on the pathophysiology, neuropathology, and clinical assessment of delirium.
The 4 A's test for delirium screening
ALERTNESS
The first item of the assessment is to approach the patient and observe. Observing at the bedside is quite clever, as an altered level of alertness is specific to delirium. They may be sleepy/drowsy or may be agitated, and if the patient is asleep, try to wake them up gently. To assist with the rating, ask their name and address.
Normal (fully alert, but not agitated, throughout assessment) 0
Mild sleepiness for <10 seconds after waking, then normal 0
Clearly abnormal +4, the score has >95% likely to be delirium
AMT 4
Item 2 and 3 focus, briefly, on the patient's cognition. After observing the patient, the AMT4 and attention is done. The AMT stands for Abbreviated Mental Test 4 and helps assess the mental impairment in elderly patients. You need to ask 4 simple questions, these are:
Age
Date of birth
Place (name of the hospital or building)
Current year
The results should be:
No mistakes 0
1 mistake +1
≥2 mistakes or untestable +2
ATTENTION
This part can be a little tricky. Instruct the patient to list months in reverse order, starting from December. If the instruction is a little confusing, you can prompt the patient by asking them the month before December.
Reach May or lists ≥7 months correctly 0
Starts but lists <7 months, or refuses to start +1
Untestable (cannot start because unwell, drowsy, inattentive) +2
ACUTE CHANGE OR FLUCTUATING COURSE
The last item focuses on time and fluctuating changes, which are highly specific for delirium. Evidence of significant change or fluctuation in alertness, cognition, other mental function/status such as paranoia/hallucination within the last 2 weeks and are still persisting in the last 24 hours.
No 0
Yes +4
INTERPRETATION
0: delirium or severe cognitive impairment unlikely
1-3: possible cognitive impairment
x≥4: possible delirium and/or cognitive impairment
Some points to remember: a score of 4 or more is suggestive of delirium, however not diagnostic. Hence, do use your clinical thinking, and a thorough mental assessment may be required to reach a diagnosis. 1-3 may require further history taking. Having a score of 0 does not eliminate delirium, do keep that in mind. The first 3 questions are rated solely on observation of the patient at the time of assessment. In contrast, question 4 will require some detective work such as your experience with the patient, other staff knowledge, GP letters, case notes, et cetera. The tester should take account of communication difficulties (hearing impairment, dysphasia, lack of common language) when carrying out the test and interpreting the score.
Case 1 - Pneumonia
Case from the 4AT Rapid Clinical Test for Delirium website, authored by MacLullich A.
Mrs SA is an 84-year-old woman with a history of dementia who lives alone and has carers attending twice a day. She is usually mobile and can go shopping and visit friends if accompanied. Mrs SA was admitted because she was not answering her phone, and her daughter had gone to see her and found that Mrs SA was very sleepy and felt hot. In the emergency department, she is diagnosed with pneumonia.
A 4AT is performed. On approach, she had her eyes closed and did not initially open them on request. When asked to say her name, she opened her eyes and attempted to say something, but this was incomprehensible. She did not respond to other requests to perform cognitive testing, including the AMT4 and Months Backwards.
Mrs SA's daughter said that though Mrs SA does have problems with her memory, she usually manages to look after herself with assistance at home. She is generally able to converse normally.
4AT scoring:
ITEM 1 – Level of alertness: score 4 (clearly abnormal level of alertness)
ITEM 2 – AMT4: score 2 (untestable)
ITEM 3 – Months Backwards: score 2 (untestable)
ITEM 4 – Acute change or fluctuation: score 4 (clear evidence of change from informant)
4AT total score: 12/12
This indicates multiple features of delirium, including an altered level of alertness, severe cognitive impairment, and acute change. Note that though cognitive testing or interview is not possible, the 4AT is still scored positive: no patients are Unable to Assess (UTA) with the 4AT.
Case 2 - Overnight change
Case from the 4AT Rapid Clinical Test for Delirium website, authored by MacLullich A.
Mr AY is a 70-year-old inpatient in a medical ward. He has a history of chronic obstructive pulmonary disease and hypertension. He had been admitted 3 days ago with a chest infection, and he had been treated with antibiotics and steroids. On admission, his 4AT score had been 0/12.
On the morning ward round, the nurse stated that Mr AY had been restless and confused overnight.
A 4AT is repeated.
4AT scoring:
ITEM 1 – Level of alertness: score 0 (normal)
ITEM 2 – AMT4: score 1 (unable to say the name of the place (hospital))
ITEM 3 – Months Backwards: score 1 (started but incomplete)
ITEM 4 – Acute change or fluctuation: score 4 (clear evidence of change from informant)
4AT total score: 6/12
This score is above the 4 or above threshold and indicates possible delirium. This mainly comes from the history of change from the informant (nurse on the ward round) and is supported by the change in cognitive function.
Case 3 - Dementia
Case from the 4AT Rapid Clinical Test for Delirium website, authored by MacLullich A.
Mr JB is an 88-year-old man who lives alone. He has a history of atrial fibrillation, stroke, depression, prostate cancer, and gout. He is admitted to the hospital after having fallen. He is accompanied by his son, who states that Mr JB has been having some problems with his memory over the last few months. He has not seen a health professional about this, and there is no diagnosis of dementia. The son said that Mr JB was his normal self at the time of the consultation.
A 4AT is performed in the medical admissions ward.
4AT scoring:
ITEM 1 – Level of alertness: score 0 (normal)
ITEM 2 – AMT4: score 2 (did not know age, year, name of the place)
ITEM 3 – Months Backwards: score 1 (incomplete)
ITEM 4 – Acute change or fluctuation: score 0 (no evidence of change from informant)
4AT total score: 3/12
This score indicates cognitive impairment. There is no clear evidence of delirium. Given this score and the son's history, further evaluation for dementia at an appropriate time may be beneficial.
Case 4 - Fractured fall
Case from the 4AT Rapid Clinical Test for Delirium website, authored by MacLullich A.
Mrs SA is a 96-year-old woman who lives in a care home. She has a history of severe dementia. She is admitted to having fallen in the care home. In the emergency department, an X-ray shows an undisplaced pubic ramus fracture.
Mrs SA had her eyes open on approach. The doctor asked Mrs SA to say her name. Mrs SA said her first name but is only intermittently responsive to other questions, including 1-stage commands. She sometimes was able to say yes or no to simple requests but did not always answer, and her answers were inconsistent.
Discussion with care home staff revealed that Mrs SA was usually unable to communicate meaningfully beyond saying yes or no. However, she was able to walk with a wheeled frame and usually could eat and drink with assistance.
A 4AT is performed.
4AT scoring:
ITEM 1 – Level of alertness: score 0 (normal)
ITEM 2 – AMT4: score 2 (untestable)
ITEM 3 – Months Backwards: score 2 (untestable)
ITEM 4 – Acute change or fluctuation: score 0 (clear evidence of change from informant)
4AT total score: 4/12
The score of 4/12 indicates possible delirium. This score results from the untestable scores on items 2 and 3.
At the time of assessment, there was no clear evidence of acute change. The 4AT is designed to allow a score of 4 when the patient is untestable because in acute settings this commonly indicates delirium. However, it is possible for patients with severe dementia and no delirium to receive a score of 4.
People with severe dementia commonly have cognitive deficits that are in practice indistinguishable from those observed in delirium, including inattention. This means that it is often difficult to determine if the patient has severe dementia alone or delirium superimposed on dementia. The diagnosis is also challenging if the patient cannot readily communicate verbally and express pain or distress through crying out or appearing restless. In such cases, it is often unclear if the patient has delirium.
The most clinically likely diagnosis is severe dementia rather than delirium in the present case. Ongoing close monitoring for change or fluctuation is needed.
Case 5 - Back pain
Case from the 4AT Rapid Clinical Test for Delirium website, authored by MacLullich A.
Mr IR is a 62-year-old man with a history of aortic stenosis, osteoporosis, vertebral fractures, depression, and alcohol dependence. He was admitted with back pain that had not responded to increased analgesia at home. A lumbar spine X-ray showed a likely new vertebral fracture.
Mr IR was treated with increased opioid analgesia with some effect.
Four days after admission, the nursing staff noted that Mr IR was expressing suspicious thoughts about his care. Also, he had appeared mildly confused and irritable at times during the night.
He was reviewed in more detail. During the consultation, he appeared unhappy and distrustful. He said that strange things had been going on overnight, with the nurses having a party and keeping the other patients from sleeping. He was angry about this and asked if he could be moved to a different ward. He also said that he had been given the wrong drugs and was concerned. He denied experiencing hallucinations.
A 4AT is performed.
4AT scoring:
ITEM 1 – Level of alertness: score 0 (normal)
ITEM 2 – AMT4: score 0 (all correct)
ITEM 3 – Months Backwards: score 0 (correct)
ITEM 4 – Acute change or fluctuation: score 4 (evidence of change from nurses, and also deduced as new paranoid thoughts likely to be acute)
4AT total score: 4/12
A score of 4 indicates possible delirium. In the present case, this is based on the evidence of change alone.
In delirium, there is usually has evidence of inattention and other cognitive deficits on one-off bedside testing. However, it is well known in clinical practice that in some cases of delirium patients may have periods of being orientated and may even only have mild inattention that is not detectable by brief cognitive tests. Cognitive deficits in delirium can fluctuate, and a one-off bedside testing episode may not yield a positive score.
In the present case, the history and the paranoid thoughts clearly indicate a high risk of delirium requiring intervention. The potential causes include opioid toxicity, pain, and alcohol withdrawal.
The 4AT is designed to allow likely delirium to be diagnosed in cases like this, even when cognitive deficits at the moment of assessment are not diagnostic.
Case 6 - Delirium
Case from the 4AT Rapid Clinical Test for Delirium website, authored by MacLullich A.
Mr EB is a 92-year man who lives in a residential home. He had a history of Alzheimer's dementia, falls, and hypertension. The paramedics were called to see Mr EB because of severe lethargy and reduced responsiveness. The history from the residential home staff was fatigue over 3 weeks, and in the last 48 hours, worsening drowsiness and reduced responsiveness. He also had a reduced appetite and reduced fluid intake for approximately 36 hours. Mr EB was normally mobile with assistance and had normal fluid and food intake.
The staff did not report any signs of distress in Mr EB.
A 4AT is performed. On entry into Mr EB's room, he was asleep, but he did open his eyes to speech and was able to give some meaningful answers. However, when the tester stopped speaking, he closed his eyes and appeared to be dozing. He denied hallucinations, and there was no evidence of delusions.
4AT scoring:
ITEM 1 – Level of alertness: score 4 (clearly abnormal level of alertness)
ITEM 2 – AMT4: score 2 (knew place, age but unable to give year, date of birth)
ITEM 3 – Months Backwards: score 1 (said 'December' but unable to say any other months)
ITEM 4 – Acute change or fluctuation: score 4 (clear evidence of change from informant)
4AT total score: 11/12
This case shows delirium, with bedside signs including the altered level of alertness and some cognitive impairment. The history clearly indicates acute change.
Published 15th November 2021. Last reviewed 5th February 2022.
Reference
Bellelli G, MacLullich A. 4 A’s Test for Delirium Screening. Mdcalc website. https://www.mdcalc.com/4-test-delirium-screening#creator-insights. Accessed January 2, 2022.
Bellelli G, Morandi A, Davis D, et al. Validation of the 4AT, a new instrument for rapid delirium screening: a study in 234 hospitalised older people. Age and Ageing, 2014;43(4): 496-502. https://doi.org/10.1093/ageing/afu021
Collins N, Blanchard MR, Tookman A, Sampson EL. Detection of delirium in the acute hospital. Age Ageing. 2010;39(1):131-5. doi: 10.1093/ageing/afp201. PMID: 19917632.
Cooper C, Hunter A, Handyside J, Henderson V, Scott DA. Easy as 4-AT: Improving Delirium Screening in Acute Elderly Admissions with a Targeted Educational Intervention – A Pilot Study: Physiology students can help the NHS identify reasons for poor staff compliance with physiology screening tools. 2019. Poster session presented at Physiology 2019, Aberdeen, United Kingdom.
Dementia United authors. Assessment test for delirium & cognitive impairment. Dementia United website. https://dementia-united.org.uk/wp-content/uploads/sites/4/2020/10/02-4AT.pdf. Accessed January 2, 2022.
MacLullich A, Ryan T, Cash H. 4 AT: Rapid Clinical Test for Delirium. The 4 AT website. https://www.the4at.com/whythe4at. Revised October 30, 2014. Accessed January 2, 2022.
