Confusional Assessment Method and 4AT

The CAM and 4AT are used to help identify those patients who might have delirium rather than dementia, and should be used in conjunction with the mini mental status examination (when there is uncertainty- e.g. where symptoms have not resolved despite treatment).  It may involve interviewing relatives, nurses etc as well as the patient.


  1. Acute onset
    1. Is there any evidence of an acute change in mental status from the patient’s baseline?
  2. Inattention
    1. Did the patient have difficulty focusing attention, e.g. being easily distractable, or having difficulty keeping track of the conversation?
    2. Did this behaviour fluctuate during the interview?
  3. Disorganised Thinking
    1. Was the patient’s thinking disorganised or incoherent, such as rambling or irrelevent conversation, unclear or illogical flow of ideas, or unpredictable switching from subject to subject?
  4. Altered level of consciousness
    1. Is the patient alert or drowsy?  Does this fluctuate?
  5. Disorientation
    1. Was, at any time, the patient disorientated in time and/or place?
  6. Memory impairment
    1. Did the patient have difficulty remembering past events or following instructions?
  7. Perceptual disturbance
    1. Did the patient experience delusions/hallucinations/illusions?
  8. Psychomotor agitation/retardation
    1. At any time, did the patient seem agitated or unusually lethargic/sluggish?
  9. Altered sleep/wake cycle
    1. Has the patient had trouble sleeping?
  • Interpretation
    • If 1 & 2 are present AND either 3 or 4, then a diagnosis of delirium can be made.

4AT- quicker and can be easier

  1. Alertness
    1. Normal (0)
    2. Mild sleepiness for <10 secs after wakening, then normal (0)
    3. Clearly abnormal (4)
  2. AMT4 (Age, DOB, place, current year) i.e. orientation in person, time and place
    1. No mistakes (0)
    2. 1 mistake (1)
    3. 2 or more (2)
  3. Attention (months of the year backwards, serial addition/subtraction)
    1. Achieves 7 or more (0)
    2. Starts but scores <7 OR refuses to start (1)
    3. Untestable (cannot start) (2)
  4. Acute change/fluctuation over the last 2 weeks and evident in the last 24 hours
    1. No (0)
    2. Yes (4)
  5. Interpretation
    1. If 4 or more- likely delirium (+/- cognitive impairment)
    2. If <4- possible cognitive impairment

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