Clocking delirium: the value of the Clock Drawing Test with case illustrations.

Screening for impaired cognition is very important in geriatric and palliative medicine. There are several validated screening tools for delirium; the Confusion Assessment Method, The Memorial Delirium Assessment Scale, and the Bedside Confusion Scale. The Clock Drawing Test, which was initially described in 1963, has also been used to assess cognition and is validated in Alzheimer's disease and in elderly hospice patients with a negative predictive value greater than 0.95. The Clock Drawing Test is quickly and easily performed by patients and can be kept in the patient's medical record for future reference. However, very few studies have used the Clock Drawing Test to assess delirium in cancer and even fewer have used the Clock Drawing Test to determine response to interventions for delirium.