Clock Drawing Test (CDT)


Clock Drawing Test (CDT) Evaluation Summary

  What does the tool measure? Visuospatial and praxis abilities, and may determine the presence of both attention and executive dysfunctions.
  What types of clients can the tool be used for? Virtually any patient population. It has proven to be clinically useful in differentiating among normal elderly, patients with neurodegenerative or vascular diseases, and those with psychiatric disorders, such as depression and schizophrenia.
  Is this a screening or assessment tool? Screening
Time to administer All variations of the CDT should take approximately 1-2 minutes to complete.
  Versions Verbal command: Free drawn clock; Pre-drawn clock;

Copy command: Copy command; Clock reading test

Time-setting: “10 after 11

The Clock Drawing Test Modified and Integrated Approach (CDT-MIA)

Languages The CDT can be conducted in any language.
Measurement Properties
  Reliability – Out of 4 studies examining test-retest reliability, 3 reported excellent test-retest and 1 found adequate test-retest.

– Out of 7 studies examining inter-rater reliability, 6 reported excellent inter-rater and 1 reported adequate (for examiner clocks) to excellent (for free-drawn and pre-drawn clocks inter-rater.


Construct: The CDT correlated adequately with the Mini-Mental State Examination and the Functional Independence Measure.
Known groups. Significant differences between Alzheimer’s patients and controls detected by CDT.

Criterion: Predicted lower functional ability and increased need for supervision on hospital discharge; poor physical ability and longer length of stay in geriatric rehabilitation; activities of daily living at maximal recovery.

  Does the tool detect change in patients? Not applicable
  Acceptability The CDT is short and simple. It is a nonverbal task and may be less threatening to patients than responding to a series of questions.
Feasibility The CDT is inexpensive and highly portable. It can be administered in situations in which longer tests would be impossible or inconvenient. Even the most complex administration and scoring system requires approximately 2 minutes. It can be administered by individuals with minimal training in cognitive assessment.
How to obtain the tool? A pre-drawn circle can be downloaded by clicking on this link: pre-drawn circle