Item	Assessment	Response	Score
1. Alertness	Observe level of alertness during the assessment.	Normal or mild sleepiness <10 seconds after waking, then normal	0
		Clearly abnormal: marked drowsiness, difficulty rousing, or agitation/hyperactivity	4
2. AMT4	Ask age, date of birth, place, and current year.	No mistakes	0
		1 mistake	1
		2 or more mistakes or untestable	2
3. Attention	Ask months of the year backwards starting at December.	Achieves ≥7 months correctly	0
		Starts but <7 months correct or refuses	1
		Untestable because of illness, drowsiness or inattention	2
4. Acute change or fluctuating course	Significant change or fluctuation in alertness, cognition or other mental function over the last 2 weeks and still present in the last 24 hours.	No	0
		Yes	4
Total 4AT score			0-12, sum of item scores

Interpretation: score ≥4 suggests possible delirium with or without cognitive impairment. Score 1-3 suggests possible cognitive impairment. Score 0 makes delirium and severe cognitive impairment unlikely if information, especially for acute change, is complete.

4 A's Test for Delirium Screening